Download Structural Organization in Animals

Structural Organization in Animals
Human body consists of 11 organ systems each composed of differing amounts of the following tissues. An organ
system is a complex mix of tissues that perform a specific task.
Tissue is a cooperative unit of cells that perform a specific task. Tissues differ in proteins that are expressed.
Four major types of tissues
Epithelial: sheets of closely packed cells called “membranes” that
Covers the internal and external surfaces, i.e. epidermis (skin) and linings of organs; Forms barriers for entry and
exit; Forms glands by folding inward (exocrine and endocrine)
Basement membrane connects inner surfaces of epithelia to underlying tissues, composed of polysaccharide and
fibrous proteins.
Three types: Squamous, Cuboidal and Columnar
 Squamous:
simple squamous is one cell layer; is thin and leaky (ie. blood vessels)
stratified is two or more cell layers thick; regenerats rapids by mitosis; covers surfaces subject to abrasion
(lining of esophagus)
 Cuboidal and Columnar are large cells ; make secretory products; form folded surfaces (lines digestive tract
forms moist epithelium and mucous membrane of lungs) hair like projections pushes dust, pollen particles out.
IDENTIFY AND DEFINE EACH
Connective: sparce population of cells scattered through an extracellular matrix. The matrix which is a web of fibers
embedded in substances that are liquid  solid, all produced by the cell. Six types:

Loose connective tissue (CT, most common), assists in holding organs in place and binding tissues
to other tissues
(dermis: nourishes the dermal tissues)
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Adipose CT is composed of fat: pads, insulates, energy storage

Blood is fluid CT. Composed of formed elements and plasma. Plasma is the fluid matrix
composed of salts and proteins (i.e. antibodies). Formed elements composed of three types of cells
(erythrocytes (rbc), leukocytes (wbc) and platelets (cell fragments, specializing in clotting). Blood
vessels transport blood which caries dissolved O2 and nutrients to cells and removes CO2 and cellular
wastes.
RBC transports O2; WBC carry immune cells

Fibrous CT the matrix is dense and contains fibers: includes tendons (connects muscle to bone)
and ligaments (connects bone to bone)
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Cartilage CT forms strong, flexible (resists shattering) skeletal material, made of collagen fiber
rolled in a rubbery substance. Round ends of bones, forms cushioning discs between vertebrae, support
of noses and ears
Bone is rigid and flexible connective tissue. Matrix of collagen embedded in calcium salts. Like
all other tissues bone is nourished by component delivered in blood. Blood vessels enter bone through
canals.
Nervous: Forms the communication network, specialized in conduction of electrical impulses. Two types of cells:
 Neurons:conduct the sensory input electrically. Three parts: dendrites, cell body and synapse.
 Neuroganglia aka glia: protects the neuron with nutrients and insulation.
Neurons can be either affector (sensing), or effector (responding) and interneurons. Involved in homeostasis
(maintaining a dynamic equilibrium) using positive and negative feedback mechanisms constantly monitoring
internal and external temperatures, moisture, pressure and nutrient content of cells.
Muscular: special ability to shorten (contract) using two proteins (actin and myosin). Function in movement. Work
in antagonistic pairs. A muscle is a bundle of long cells called fibers. Three types vary in arrangement of the actin
and myosin proteins:
 Skeletal: responsible for voluntary movements: are striated and unbranched
 Cardiac: cause involuntary contractions of the heart. Cells are striated and branched
 Smooth: Causes slow, steady, strong, involuntary movements in intestine, air passageways in lungs and other
hollow organs.
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Organ system 1: Reproductive System
Human development begins with fertilization of 2 haploid cells (sperm and egg) to produce 1 diploid cell –
zygote.
Gametes are produced by meiosis (reduction division) in the sex organs called gonads (ovaries and testes).
Gamete production is control by hormones produced in the pituitary glands and in regions of the gonads.
Sperm production occurs continuously within the seminiferous tubules in the testes. Sperm and androgen
production are under the control of the FSH and LH produced in the pituitary gland in the brain. FSH increases
production of sperm by testes. LH promotes secretion of androgens, mainly testosterone.
Testosterone is produced by the interstitial cells scattered between the seminiferous tubules in the testes.
Testosterone has numerous effects, promotes maturation and development of accessory sex organs, proliferation of
body hair, thickening of the skin, enlargement of the larynx, increased glandular secretions (sweat and body odor),
increased metabolic rate and male patterned baldness.
Spermatozoan are produced immature (without flagella and a head) then travel travels to the epididymis and
matures.
Sperm cells are small and packed with mitochondria (energy) and consist of a nucleus, flagellum and a head
“acrosome” essentially a lysosome (contains hydrolytic enzymes that digest the cervical mucus and the protective
coating around the egg).
Testes descend from the body cavity into the scrotum during the ninth month of fetal life.
Penis erection is accomplished by blood flowing into the spongy erectile tissues
During ejaculation sperm travels through the vas deferens over the bladder
Through the seminal vesicles, prostate gland and bulbourethral gland. The peak in sexual arousal promotes
muscle contraction of these organs. As it travels it picks up a milky alkaline fluid, fructose and a mucoid
secretion. The vas deferens joins the urethra. Sperm plus secretion make semen typically >300 million sperm/
ejaculation (fertile males) and <100 million (infertile)
Female System: Oocytes in women are stored in the ovaries nurtured in a complex of cells and fluids called
follicles. At birth she has produced 40,000 and 400,000 follicles. Once a month, every 28 days, she ovulates :the
oocytes mature into an egg and travels down the uterine tube (aka fallopian). During her reproductive years she will
use only a few hundred of these follicles. Oogenesis is the process by which and egg is made from a germ cell.
Meiosis produces 3 polar bodies and 1 egg cell.
FSH stimulates follicle maturation to produce egg cell
LH stimulates the release of the egg from the ovary and stimulates the secretion of estrogen and progesterone to
prepare the endomedrium lining for implantating
Menstral Cycle:
Day 1-7: Bleeding (low estrogen and progesterone) due to breakdown of endometrium
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Day7-14: Following bleeding: Low EST and PRO signals pituitary to secrete FSH and LH Stimulate several
follicles; Follicles secrete estrogen which causes regrowth of the endometrium.
Day 14: ovulation. Egg release. Due to surge in LH, ruptures dominant follicle. Remaining follicle develops into
corpus luteum secreting PRO and EST. Endomedrium prepared for fertilization and implantation . Lining secretes
EST and Pro
If fertilization and implantation does not occurs, the corpus luteum disintegrates. EST and PRO levels increase and
new ovarian cycle is initiated.
Fertilization  EST and PRO remain high. Corpus luteum is maintained eventually replaced by the placenta. High
EST and Pro inhibit pituitary FSH and LH.
Organ system 2: Integumentary System
Functions: protection, sensing, controls evaporation of body fluids and heat loss.
Includes skin (epidermal (composed of epithelial cells)and dermal layer), exocrine glands are embedded in these
layers, hair follicles and associated glands and nails, nerve fibers and associated touch and pressure receptors
Several exocrine glands that excrete salt water, oils and milk
Organ system 3: Skeletal system
The human body is made up of over 200 bones of different shapes and sizes. Bones have living cells (called
osteocytes) bound together by a hard, calcium-like material. This makes the bone strong and rigid. The bones are
hollow and filled with a spongy material, called marrow.
The joints of the bones are covered in cartilage - a tough, flexible material, rather like gristle. As cartilage is more
elastic than bone it allows the bones to move freely at the joints. It also cushions the bones at the joints to stop them
rubbing against each other.
The bones have several important functions.

The skeleton gives the body rigid support and the joints act as levers so that the body can move.
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They protect organs in the body; for example, the ribcage protects the heart and lungs.
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The bones also store some of the body's essential minerals, especially calcium.
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Produces the blood cells in marrow
Marrow produces three different types of blood cells:
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Red blood cells which carry oxygen to all cells in the body
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White blood cells which are essential for fighting infection
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Platelets which help the blood to clot and prevent bleeding
Stem cells are blood cells at the earliest stage of development in the bone marrow. They develop into the different
blood cells described above. They can be taken from the bone marrow or collected from the bloodstream
Bones are made of two different types of bony tissue.
Compact bone is smooth, hard material that covers the surface of bones. It is thickest around the shaft of
the bone.
Spongy bone has small spaces and is more brittle than compact bone. It is found at the ends of bones under
a layer of compact bone.
Three types of cells work together in bone regeneration: osteoblasts, osteocytes, osteoclasts.
The osteon is the fundamental unit of the bone
Osteon Structural unit of compact bone. Composed of concentric bone lamellae with osteocytes located in between.
Osteoblast building cells aid the growth and development of teeth and bones. It secretes the ground matrix rich in
collagen and embedded in calcium and phosphorous. Ca and P are minerals derived from blood. Balance in Ca and
P levels is determined by vitamin D (calcitrol), thyrocalcitonin (lowers blood Ca) and parathormone raises Ca levels
in the blood to normal.
Osteocytes are osteoblasts that have become dormant. They are osteoblast that have become surrounded by
hardened matrix material. They are reactivated during breakage or fracture.
Osteoclast is a cell that actively reabsorbs old or fatigued bone so that new bone may be replaced by osteoblast cells.
When osteoclast cells reabsorb bone faster than the osteoblast cells are building it, then osteoporosis (bone loss)
occurs
The skeleton and muscles interact in movement
Muscular System includes all of the skeletal muscles under voluntary control. There are 630 muscles in
the human body.
40% of the body is skeletal muscle. Skeletal muscles are striated, non-branching under voluntary control.
5-10 % of the body is cardiac and smooth muscle. Cardiac and smooth muscle are not a part of the
muscular system, under involuntary control.
Functions of Muscles:
 maintain balance and posture
 provide heat as a result of the muscle contraction.
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Muscles are organs in that they contain a variety of tissues, connective, nervous and skeletal muscle.
Muscle fibers come together at the ends to form tendons that attach to bone. Each muscle has within it a number
of fascicles (oval shaped bundles)
Inside each fascicle is a long muscle cell called a fiber, each is the length of the muscle and is multinucleated.
Because these cells are elongated they are called fibers.
Inside the fibers are myofibrils (more long thin structures).
The components of muscle:
Myofibril  Fiber Fascicle  Muscle
Each myofibril is composed of contracting units called sarcomeres, joined end to end at Z-lines.
Each sarcomere is composed of thick filaments, containing mostly myosin surrounded by 2 thin filaments
composed largely of actin filaments but also tropomyosin and troponin.
The sarcomere that is the functional unit of muscles. Thick myosin filaments lie in the middle of the
sarcomere and thin filaments are attach to either end of the sarcomere.
During contraction, thin filaments slide towards each other to the center of the sarcomere
Contraction is aided by the myosin heads that have a pivoting action. Movement is the result of contraction of
opposing or antagonistic muscle. For the arm to extend one muscle extends while the opposing contract. Muscles
only contract. Relaxation is passive, thin filaments move away from each other and from the center of the
sarcomere, detaching from the myosin only when an opposing muscle contracts.
Contraction of a Muscle requires an Action potential and is signaled by an excited Neuron
Contraction in skeletal muscle begins with an action potential in the muscle fiber. This causes the release of
calcium from the sacroplasmic reticulum. The action potential in the muscle fiber begins after it is excited by an
excited neuron. An action potential is an electrical change across a cell membrane due to changes in the conduction
of ions across the membrane.
Calcium’s Role : When calcium is present it binds to the troponin which changes in shape causing the movement of
tropomyosin off the active sites so that myosin and actin can interact through the myosin heads and muscle
contraction can occur. When calcium is removed the active site is covered up again preventing binding of myosin
heads to actin.
Cellular energy, ATP, is needed to releases the head from the actin filament and cocks it for the next ratchet
power stroke.
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Energy is required to break the bond between the myosin head and the actin active sites as well as for removal of
calcium from the cytoplasm by the use of a special pump within the sarcoplasmic reticulum. When the myosin head
is tilted forward, after the power stroke, a binding site for ATP (the chief energy currency of the cell) is exposed.
At rest and during light exercise, muscles use lipids as their energy source. During heavy exercise muscles use
carbohydrate.
Energy is retrieved from foods and stored substances via Cell Respiration.
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Sources of high energy phosphates :phosphorylcreatine and ATP
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Fermentation or Anaerobic Respiration: When oxygen supplies are inadequate lactic acid builds up in the
muscle. An oxygen debt exists. Oxygen is used to convert the lactate into carbon dioxide and water and
replenish energy stores.
Muscle Fatigue: Prolonged strong contractions leads to fatigue of the muscle caused by the lack of adequate
supplies to maintain the work load.
Hypertrophy is an increase in muscle mass caused by forceful muscular activity. The diameters of individual fibers
increase, nutrient and metabolic substances increase, mitochondria may increase, and the myofibrils also increase in
size and number. Muscular hypertrophy increases the power for muscle contraction and nutritive mechanisms for
motioning that increased power.
Atrophy results when a muscle is not used for a length of time or is used for only weak contractions. As little as one
month of disuse can sometimes decrease the muscle size to one half normal. Damage to the nerve to a muscle results
atrophy a well. If the damage is repaired in the first 3-4 months the muscle will regain full function. After four
months muscle fibers will have degenerated to fibrous and fatty tissue.
Smooth Muscle
Smooth muscle is found in the walls of blood vessels, tubular organs such as the stomach and uterus, the iris, or
associated with the hair follicles. Smooth muscles exists as a sheet or bundle of fibers that are intimately connected
by junctions that allow ions to flow freely. When one portion of smooth muscle is stimulated the action potential
spreads to all other fibers.
Most of the same contractile proteins are present and active in smooth muscle contraction but they are not arranged
as microscopically visible parallel myofilaments as in skeletal muscle.
Cardiac Muscle
The heart is made of specialized muscle tissue with some similarities to both smooth and skeletal muscle. It is
involuntary and mononucleate as is smooth muscle. Cardiac muscle is striated like skeletal muscle which means that
it has microscopically visible myofilaments arranged in parallel with the sarcomere structure described above. These
filaments slide along each other during the process of contraction in the same manner as occurs in skeletal muscle.
Cardiac muscle fibers branch and have a single nucleus per cell. Another difference in cardiac muscle is the
presence of intercalated discs that are specialized connections between one cardiac muscle cell and another. These
tight connections allow for almost completely free movement of ions so that action potentials can freely pass from
one cell to another. When one cell is excited the resultant action potential is spread to all of them. This is an
important feature in that it allows the atrial or ventricular muscle to contract as one to forcefully pump blood. Action
potentials in cardiac muscle are also specialized to maximize the pumping function of the heart. They last 10 to 30
times as long as those of skeletal muscle and cause a correspondingly increased period of contraction.
Duchenne muscular dystrophy is an X-linked gene disorder that makes a non functional protein called
dystrophin. Age at onset: two to six years; symptoms include general muscle weakness and wasting; affects pelvis,
upper arms, and upper legs. The exact function of dystrophin is unknow by is involved in Ca handling in muscle
cells.
The Nervous System
Includes the brain, spinal cord and peripheral nerves. Two main divisions: the CNS , central, (includes the brain and
in vertebrates, spinal cord) and the PNS, peripheral, nervous systems. Nerves are made of bundles of neurons and
neuroglial cells. Neurons are cells with an elongated region called an axon, and numerous extensions called
dendrites. In humans, neurons can grow up to a meter long. All the functions of the nervous system involve neurons
communicating either with one another, or with cells of other types. The PNS carries information either from the
sensory receptors to the CNS or from the CNS to the effectors.
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Three types of neurons
Sensory Neurons, sense conditions both inside and outside the body including touch, temperature and
pressure and sight, smell, hearing and taste. They carry information from the sensory receptors to the CNS.
Interneurons are located only in the brain and spinal cord. They are responsible for analysis, integration or
processing of sensory inputs and coordination of motor output. The CNS consists of the brain and spinal cord, they
are responsible for integrating and coordinating sensory data and issuing action or motor commands.
Motor neurons carry signals from the CNS to effectors, such as skeletal muscles or gland cells. Effectors
responding to the signal usually with a motor output
Sensory Neurons   
Interneurons
   Motor Neurons
In General, the communication between nerve cells is a result of changes in the electrical properties of the
neuron’s outer lining or plasma membrane.
The Neuron’s Composition
The Cell Body houses the nucleus and most of the organelles
Dendrites are short numerous, highly branched extensions that convey signals toward the cell body
Axons are long and unbranched; they convey signals away from the cell body toward other neurons or
effectors
Synaptic Knob located at the end of axons, they relay the signal
Neuroganglia Support Neurons. Perhaps there are 50 neuroglia to every 1 neuron. These cells protect, insulate
and reinforce the neuron.
Sensing causes a cell at resting potential to go to action potential. A resting nerve cell has a negative
charge inside relative to outside. The negative charge inside is maintained by negatively charge , large organic
molecules inside and an excess of K+. When a stimulus is applied to a nerve cell Na+2 is pumped inside the axon of
the nerve cell, the action potential is triggered. When Na+2 channels close K+ channels open, K+ rushes inside. The
cell returns to its resting potential.
The action potential is a localized electrical event. The electrical signal change moves down the neuron, like a
domino affect.
The action potential is transferred from cell to cell via a synapse. At the synapse the electrical potential is
converted to a chemical signal. The chemical signal is a neurotransmitter molecule. Neurotransmitters promote
changes in the cells capable of producing desired effects. (release of digestive enzymes, insulin, affect Ca +2 stores).
The signal is eventually transferred to the central nervous system (brain and spinal cord) for processing. With
processing a decision must be made, which part of the body will be involved.
Neurotransmitters
 Acetylcholine: slows heart rate causes muscle cells to contract.
Function as hormones: epinephrine, norepinephrine (increases heart rate)
 Serotonin and dopamine (affect sleep, mood, attention and learning)
The Brain is the master control center, directing output through the spinal cord and including homeostatic centers,
sensory centers and centers of emotions and intellect. Information is carried to and from the brain by the cranial
nerve and to and from the spinal cord by the spinal nerve. In the interiors of the brain is a hollow space filled with
fluid called the cerebrospinal fluid. Neurons in the brain are surrounded by myelin.
Myelin is the fatty covering that insulates nerve cell fibers in the brain and spinal cord to assist the high-speed
transmission of electrochemical messages between the brain, the spinal cord, and the rest of the body. When myelin
is damaged, transmission of messages may be slowed or blocked completely.
The peripheral nervous system forms a vast intercommunicating network. Motor neurons are either under voluntary
control (somatic system carrying messages to skeletal muscles) or out of conscious control (autonomic system
carrying messages to glands and smooth muscles.
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The autonomic system is either SYMPATHETIC or PARASYMPATHETIC. The two components act to
regulate the internal environment.
Parasympathetic division is associated with REST AND REPOSE it primes the body for digesting food
and resting, activities that gain and conserve the body’s energy supply. Including stimulation of all digestive
processes and slowing the heart and breathing rates.
Sympathetic division is associated with FIGHT OR FLIGHT. It prepares the body for intense, energyconsuming activities. Included is inhibition of digestion, increasing the heart and breathing rates, stimulation of liver
to release glucose and adrenal glands to release the fight or flight hormones (epinephrine and norepinephrine).
Neurotransmitters and Moods:
When your neurotransmitters are low, you are at a higher risk of developing mood-related medical problems.
When your body experiences stress, it releases neurotransmitters in response to the stress. The more stress, the more
neurotransmitters are released. Extreme cases, you can deplete your store of neurotransmitters. Many antidepressant
drugs are serotonin reuptake inhibitors.
What is Parkinson's disease?
Parkinson's disease is a slowly progressing, degenerative disease that is usually associated with the following
symptoms, all of which result from the loss of dopamine-producing brain cells: tremor or trembling of the arms, jaw,
legs, and face.
The Central Nervous System
The central nervous system is divided into two parts: the brain and the spinal cord.
The adult brain weighs 1.3 to 1.4 kg (approximately 3 pounds).
The brain contains about 100 billion nerve cells (neurons) and trillons of "support cells" called glia.
The Three Lobes of the Brain
Hindbrain: includes the Brain Stem and Cerebellum
The brain stem is the area of the brain between the thalamus and spinal cord and includes the medulla, pons and
reticular formation.

Functions of the Brain stem :Involved in involuntary activities such as Breathing, Heart Rate and Blood
Pressure
The cerebellum "little brain." is located behind the brain stem and like the cerebral cortex it is divided into
hemispheres and has a cortex that surrounds these hemispheres.

Function: coordinated muscle movements
Midbrain: Hindbrain and midbrain form the brain stem
Function:integrates auditory information, coordinates visual reflexes and relays sensory data as well as Eye and
Body Movement
Forebrain: includes Thalamus, Hypothalamus, Pituitary Gland, Cerebral Hemispheres and Limbic System
Functions: site of most sophisticated integration
 Thalamus: Contains cell bodies or neurons and relays information to the cerebral cortex. It receives
sensory information and relays it and vice versa.
 Hypothalamus: Regulates homeostasis, i.e. controls hormonal output of the pituitary gland. It controls the
pituitary gland, body temperature, blood pressure, hunger, thirst, biorhythms, sexual urges, emotions.
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
Limbic System: is a group of structures that includes the amygdala, the hippocampus, mammillary bodies
and cingulate gyrus. These areas are important for controlling the emotional response to a given situation.
o The hippocampus is also important for learning and memory
o The amygdala

The cerebrum has two hemispheres that divides it into left and right halves. Each hemisphere
communicates with the other through the corpus callosum, a bundle of nerve fibers.
The rational left (logic and mathematical ability)
The intuitive right (imagination, special perceptions artistic ability and emothions)
The four lobes of the cerebral hemispheres do specific tasks
Rich bed of neurons and synapses. It produces reasoning, language, imagination, artistic talent and
personality
1. Temporal lobe: smell, hearing, auditory association
2. Frontal lobe: speech
3. Parietal lobe: speech, taste reading
4. Occipital lobe: vision

The basal ganglia are a group of structures important in coordinating movement.
The spinal cord is between 45 cm long and weighs about 35-40 grams.
The vertebral column, the collection of bones (back bone) that houses the spinal cord, is about 70 cm long.
The Five Senses:
Vision: The eye has three layers and is filled with a jelly like fluid called the vitreous humor.
1. Sclera: includes the cornea.
Cornea is a tough transparent membrane and provides 80% of the refractive power of the system. The
front chamber of the eye, immediately behind the cornea, is filled with the watery aqueous humor
2. Choroid: includes the Iris gives the eye its color, muscles of the eye and the transparent lense.
Lens is crystalline and 4 mm thick and provides 20% of the refracting power of the eye. It is pliable, and
changes shape to accomplish accommodation for close focusing.
cataract is clouding or darkening of the lens
3.
Retina: houses the photoreceptors, rods and cones. Photosensitive cells called rods and cones in the retina
convert incident light energy into signals that are carried to the brain by the optic nerve.
Receptors most highly concentrated in the fovea.
Common Defects: Myopic: nearsighted Farsighted: Astigmatism
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Endocrine System
Endocrine System is involved in sending signals to the body. It consists of more than a dozen glands.
The endocrine system controls whole-body activities such as Metabolic Rate, Growth, Maturation and
Reproduction. These hormones are secreted into the blood different from exocrine glands that secrete into body
cavities (the GI tract). The endocrine and nervous systems are closely associated.
Functions of Glands:
 Produce Steroid hormones that are lipid based and Non-Steroid hormones that are amino acid based. Most
glands produce amino acid based hormones. Steroid hormones are produced by the sex glands (testes and
ovaries) and the adrenal cortex.
 Secrete hormones and enzymes that regulate activities in cells. Hormones are chemicals signals that
coordinate body function. They have a controlling effect on specific target cell in other parts of the body.
List of Endocrine Glands
 Hypothalamus located in the brain, is the endocrine system’s master control center.
a. It receives information from the nerves about internal and external conditions.
b. It signals the pituitary gland when to secrete hormones using inhibiting and releasing factors. For
example the hormone oxitocin, induces contraction of the uterine muscle is secreted by the
pituitary gland and is regulated by releasing hormones.
c. It stimulates the medulla of the adrenal gland
 Pituitary Gland located in the brain, also produces growth hormones and endorphins (the body’s natural
painkillers). The release of the sex hormones is controlled by hormone in the hypothalamus and pituitary
glands (FSH and LH).
Two lobes of pituitary:
Anterior lobe produces
a. adrenocorticotropic hormone (ACTH),
b. Thyroid stimulating hormone (TSH)
c. growth hormones which promote enlargement of body parts,
d. prolactin (PRL) promotes milk production
e. follicle stimulating hormone and leutinizing hormone
Posterior lobe releases hormones made by the hypothalamus
a. antidiuretic hormone (ADH) promotes water retention
b. oxitosin (prostate gland in males and uterus and mammary gland in females)
 Pineal Gland links environmental light conditions with activities that show daily or seasonal rhythms. It
cues reproductive activity and sleep patterns. It secretes malatonin.
 Thyroid and Parathyroid regulates development and metabolism: located in the throat.
Thyroid Gland Produces two hormones, thyroxine and calcitonin. These hormones function in homeostasis.
Thyroxine controls early development of bone and nerve cells. It maintain normal blood pressure, heart rate,
muscle tone and digestive and reproductive functions “metabolic rate”. Calcitonin lowers blood Ca +2.
Parathyroid hormones raise blood Ca+2.
Hyperthyroidism caused by an excess of these three hormones in the blood, causes the individual to overheat,
sweat profusely, become irritable, develop high blood pressure and loose weight. Hypothyroidism caused by an
inactive thyroid, individuals are cold, gain weight and are lethargic. Deficiencies in iodine cause the thyroid to
enlarge into what is called a goiter these individual have hypothyroidism.
The thyroid also regulates the amount of calcium in cells. Calcium is involved in blot clotting, transport of
molecules across membranes, muscle contractions and more. Calcitonin (hormone) affects Ca+2 levels by affecting
its distribution in a) bones b) uptake in intestines and c) uptake in kidneys.
 Thymus produces the hormone thymosin involved in development of the immune system
 The adrenal glands mobilize responses to stress. Adrenal Glands are located on top of each kidney.
Each produces hormones related to responding to stress. Stressful stimuli activates the hypothalamus to
stimulate the adrenal medulla. It releases epinephrine and norepinephrine into the bloodstream.
Epinephrine (adrenalin) dilates blood vessels in the brain and skeletal muscles but constricts vessels elsewhere
(directing blood to critical areas)
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Nor-epinephrine (nor-adrenaline) are produced in response to positive emotions-extreme pleasure.
Both of these hormones stimulate
1) the liver to secrete glucose needed to make energy for fuel
2) increase blood pressure, breathing rate and metabolic rate and change blood flow patterns.
 Pancreatic hormones manage cellular fuel
Pancreas near the stomach: involved in digestion, secretion of digestive enzymes, and Insulin (hormone) that lowers
the levels of glucose and glucogon that raises the level of glucose by release the stores of glycogen.
Insulin and Glucogon are antagonistic.
Insulin regulates blood glucose by stimulating all body cells to take more glucose from blood. Most glucose is
converted to glycogen, by the liver. Glucose is metabolized into energy, stored fats and proteins (Cellular
Respiration).
Glucogon stimulates the liver to convert glycogen to glucose or fatty acids and amino acids to glucose, when blood
glucose levels fall as during a fast or during rigorous exercise.
Diabetes mellitus, is a hormonal disease involving insulin. Individuals cannot absorb glucose from the blood. It
occurs when there is not enough insulin or when body cells do not respond to insulin. The cells do not use glucose
and begin using fats and proteins. The body continues to accumulate glucose during digestion eventually glucose
accumulates and ultimately is detectable in urine. Insulin supplements or special diets with minimum carbohydrates
are the usual treatments.
Hypoglycemia, in contrast, individuals who are produce too much insulin causing blood glucose levels to drop
severely below 70mg/100ml. Individuals become weak, hungry, sweating and nervous eventually convulsions may
develop. Individuals should eat more frequently.
 The gonads secrete sex hormones
Sex glands make sex hormones (androgen, estrogen and progesterone) supporting egg and sperm formation,
maintains male and female secondary characteristics. All three are found in male and female.
Females have a higher ratio of estrogen to androgen. Males have a high ratio of androgens (testosterone) to estrogen.
The production of these hormones is regulated by the release of FSH and LH by the pituitary gland.
Estrogen stimulates the development and maintenance of female reproductive system and secondary sex
characteristics (smaller body size, higher voice, breasts and wider hips). Progestin prepares the uterus to support the
developing embryo.
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Immune System and Response
Lymphatic or Immune System is a part of the defense function. Consists of a network of lymphatic
vessels, lymphoids and leucocytes (white blood cells). Functions:
a)
To fight infections. Fluid enters the lymph system through open lymphatic capillaries. As it circulates
through lymph organs microbes and cancer cells are phagocytized
b) To return excess fluid from the interstitial fluid to the circulatory system. The lymph empties into the
circulatory system.
Individuals in good cardiovascular health with good dietary practices have stronger immune systems, and
are less likely to become ill.
Vessels: open vessel system that collects extracellular fluid and deliver it as lymph to the blood vessels of the
cardiovascular system. While in the lymphatic system it is checked for infection.
Lymphoids include small lymph nodes and organs that produce immune cells that destroy disease-causing
invaders
Lymph nodes are concentrated areas of branched ducts containing large numbers of lymphocytes (B cells
and T cells) and macrophages. During an infection these areas become activated and swell, causing tenderness and
aches and pains associated with a systemic infection.


Lymph organs include the thymus, tonsils, appendix, spleen and bone marrow
Thymus gland using hormone, thymosin, stimulates development of white blood cells (lymphocytes) in
early life, specifically T-cells.
Tonsils, spleen and bone marrow produce B-cells
Lymphocytes (wbc) have a variety of functions. Certain white blood cells are required to make these antibodies, T
cells, B cells, neutrophil and macrophage.
Two types of responses:
1. Non-specific defense does not distinguish between infectious agents and involves
 maintaining a physical barrier to the organisms involves:
- the epithelium is tightly packed and has
- keratin protein that acts as waterproofing, hairs
- glandular secretions prevent scraping
- sweat washes away microorganisms
- cells produce mucus, acids
- urine flush passageways
 White blood cells attack invading organisms:
- phagocytes remove pathogens by cell-eating.
- natural killer cells survey tissue for normal and abnormal cell. An abnormal cell (cancer cell) when
detected is bombarded with a protein that causes cell lysis.
 Chemical Warfare during non-specific defense
-Interferon proteins are antiviral compounds that interfere with replication
-Complement protein activation, enhances phagocytosis, destroys the membranes of invading cells and
promotes inflammation.
-Histamine and heparin proteins promote inflammation to create or repair a barrier, slowing the spread of
pathogens. They increase blood flow causing swelling, redness, heat and pain.
-Fever is regulated by nerve cells in the hypothalamus. Infections, invasions reset the thermostat. High
body temperature speeds up the activities of the immune system. Prolonged high fevers disrupt or damage organ
systems.
2. Specific defense protects against one type of infection.
It involves the antigen-antibody response that creates a type of memory. Antibodies are created by immune system
in response to an antigen. An antigen is any foreign substance that can elicit the production of antibodies. The
specific response is more effective. It is characterized by specificity, memory and prompt response to an
antigen.
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It involves antigen/antibody binding
An Antigen is any molecule that elicits a response. In terms of pathogens these molecules are on the surfaces of
viruses, bacteria or fungi (molds). Often they are proteins but can be other molecules.
An antibody is produced specific to the antigen. The antigen remains in the system (blood and lymphatic system).
On a second invasion, the antibody recognizes the antigen.
Two Types of Specific Responses involving B or T lymphocytes
1. Humoral Response. Substances from cells are released into the blood
Lymphocytes are also derived from stem cells in the bone marrow. They include:
B cells, involves the humoral response, carry the antibody to the plasma, cells or interstitial fluids. B cell
have antigen receptors (antibodies) attached to their outer surfaces. Upon invasion by pathogen, they bind
to the antigen. They are then stimulated to proliferate. Now, all of these identical effector cells secrete
specific antibodies.
Once antibody/antigen binding occurs there is precipitation out of solution and attack by
phagocytes or activation of complement proteins that lyse invaders.
2. Cell Mediated Response
T cells, involved in cell mediated response, travel inside bloodstream. There are several types of T cells.
Killer T-Cells (Cytotoxic T-cells, CTL, recognize and attack pathogen-infected cells and are the only T
cells that kill.
Helper T (T4 or CD4) cells must be activated. Once activated they secrete interleukin proteins to promote
an immune response. For example the secretion of interleukin-2 amplifies both the humoral and cell-mediated
response, bringing into play B-cells.
Supressor T-Cells (T8 or CD*) suppress the activity of other lymphocytes so they don’t destroy normal
tissue
APC= antigen presenting cells: these cells ingest a microbe and display both a self-protein/foreign antigen
on its surface. Helper T-cells bind to this complex and are as a result activated to produce interleukin-2 and
stimulate the production of cytotoxic T cells and B-cells (humoral response). These cells destroy the foreign cell.
Overall: Our cells have fingerprints and the immune system depends on recognizing the fingerprints. It has to
distinguish “self from non-self”. It is the proteins that are on the plasma membrane that determine self. These
proteins are inherited in the genes. Therefore, only identical twins can have identical set of self-proteins.
Organ transplants are rejected because of the differences in self-proteins. Organ rejection is minimized by finding
a donor with matching self-proteins and/or using drugs that suppress the immune response. You can imagine the
other complications caused by suppressing the immune response.
Disorders of the Immune System
1.
Autoimmune diseases the immune system turns against its own body cells (rheumatoid arthritis, insulin
dependent diabetes, Crohn’s, lupus) Autoimmune diseases can each affect the body in different ways. For instance,
the autoimmune reaction is directed against the brain in multiple sclerosis or the gut in Crohn's disease or
destruction of insulin-, producing cells of the pancreas in Type 1 diabetes mellitus. In other diseases, such as
systemic lupus erythematosus (lupus), affected tissues and organs may vary among individuals with the same
disease.
2.
Allergens elicit the production of antibodies. These antibodies promote the production of histamine.
Histamines are produced in amounts greater than normal causing symptoms like nasal irritation, itchiness and tears.
Antihistamines interfere with histamine action and give temporary relief. Excessive release of histamines can cause
anaphylactic shock which can lead to death.
3.
AIDS is caused by HIV a RNA virus. HIV attacks T-helper cells destroying the humoral and cell-mediated
immunity. Currently treatment with the triple cocktail postpones the development of AIDS. New approaches to
treatment include injecting patients with HIV-resistant stem cells and the development of a vaccine.
Concerning AIDS due to HIV infections, helper-T-cell count is most important.
A blood test showing the number of T4 cells you have tells you how health your immune system is
especially for AIDS and when to start taking the medications. T4 cells are the main target of HIV. Normal T4 count
is between 500 and 1500 cells/mm3. Individuals with AID show a drop of 50 to 100 cells per year. T4 below 200
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allows for opportunistic infections (Pneumocystis carinii pneumonia). Individuals with T4 counts around this level
should begin prophylactic treatments (prevents opportunistic infections). T4 counts 350 and lower are a good time to
start the anti-Hiv therapies.
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Cardiovascular (Circulatory) System
Cardiovascular System includes the heart, blood and blood vessels. It includes bone marrow where red
blood cells are formed. It functions in transport of nutrients, dissolved gases and hormones to tissues throughout the
body and removal of waste from tissues to areas of filtration (kidneys).
1) Blood has two major components:
A) Formed elements includes red blood cells (erythrocytes) which transport O2 to tissues and
removes CO2, white blood cells (leukocytes) a number of cells types that function in the immune response
and platelets small fragments of cells that contain enzymes and factors involved in clotting. Oxygen is
transported through the body bound to the protein hemoglobin. In the blood stream leukocytes are
transported to sites of injury and invasion. Once at a problem site they engulf pathogens.
B) Plasma is water, protein and other solutes. Major proteins include 1) albumins used in
transport of hormones, fatty acids 2) globulins (immunoglobulins) that function as antibodies, 3) fibrinogen
involved in clotting.
2) Blood is transported through blood vessels. Vessels are larger closer to the heart and the farther away the
smaller they are. Vessels are made of epithelial, muscle, and connective tissue. The muscle tissue is involved in
pumping blood. Constriction increases the pressure inside the vessel, relaxing decreases the pressure and increases
the diameter.
A) Arteries carry blood away from the heart, it is typically oxygenated (except when going to the
lungs)
B) Veins return blood to the heart typically deoxygenated and prevent a backflow of blood (in the
other direction) by a series of valves.
C) Capillaries are the smallest and they connect the arteries with veins. At the capillary beds gas,
nutrients and waste are exchanged between the blood and the body’s tissues. Substances move out of the arteriole
end of the capillaries by blood pressure and move into the venous end of the capillaries by osmotic pressure.
Glucose, O2, nutrients, hormones move out while CO2 and waste move into the venous end of the capillary, driven
by a concentration gradient.
3) The heart is an organ about the size of the fist, that pumps blood through the blood vessels. During
pulmonary circulation blood flows between the heart and the lungs, the heart pumps deoxygenated blood from the
heart to the lungs and oxygenated blood derived from the lungs is pumped into the heart. Systemic circulation,
once oxygenated, the heart pumps oxygenated blood to the rest of the body and deoxygenated blood is returned to
the heart.
Closed Circulatory Systems: Many invertebrates Arthropods (crabs and insects) and Mollusks (clams) have open
circulatory system. Blood is pumped by one or more hearts through open-ended vessels. The heart has pores that
function as valves, pulling blood in from tissues.
Open Circulatory Systems: Many Invertebrates, and all vertebrates. Blood is confined to vessels this keeps it distinct
from interstitial fluid. In the closed system the atrium receives and the ventricle pumps out.
Fish have a two chambered heart (one atrium and one ventricle). Fish pump only O 2 -poor blood
Humans have a four chambered heart ( 2 atria and 2 ventricle). Two circuits, one circuit the pulmonary
circuit carries blood from the right side of the heart to the lungs then to the left side of the heart. The systemic circuit
carries blood from the left side of the heart to the rest of the body.
The Flow of Blood
The flow of blood follows this path a) right ventricle to lungs via pulmonary arteries, b) lungs to left atrium via
pulmonary veins, c) left atrium to left ventricle d) left ventricle to all body organs via aorta e) body organs to right
atrium via superior and inferior vena cava f) right atrium to right ventricle.
The aorta is the largest vessel in the body, its first branches are to the most critical organs, first the heart itself then
the brain.
The structure of the blood vessels match their functions
1. The thin walls of the capillary cells facilitate diffusion of molecules to and from the interstitial fluids.
2. The arteries are composed of thick wall cells, they are under pressure produced by the heart.
3. Veins, are like arteries, and they have valves, to prevent backflow

The body of an adult contains over 60,000 miles of blood vessels!

An adult's heart pumps nearly 4000 gallons of blood each day!
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
The average three-year-old has two pints of blood in their body; the average adult at least five times more!

A "heartbeat" is really the sound of the valves in the heart closing as they push blood through its chambers.
Disease of the cardiovascular system consists of things that compromise the pumping ability of the heart, involve
failure of the directional aids (valves), or narrowing or failure of the pipes. The heart and blood vessels are not
immune to infectious agents or toxins that can decrease function. Injury or failure of the cardiovascular system,
especially the heart, is a critical problem in that peripheral tissues depend on the delivery of nutrients and the
removal of wastes through the blood vascular system.
What causes a heart attack?
A heart attack is death of cardiac muscle cells technical term “Myocardial Infarction” caused by a lack of blood
flow. The lack of blood flow to the heart results in a lack of supply of oxygen and other nutrients. Cardiac muscle
cells atrophy do not regenerate, but leave non-contracting scar tissue. This lack of supply is caused by closure of the
"coronary artery" that supplies that particular part of the heart muscle with blood. This occurs 98% of the time from
the process of arteriosclerosis ("hardening of the arteries") in coronary vessels.
"Embolus is a blood clot which is formed elsewhere and then travels to the coronary artery
"Angina" is the pain that may be felt when there is a temporary imbalance between the heart muscle's demand for
blood and the ability to deliver enough blood through the arteries
Cholesterol : There are different types of cholesterol, or at least different molecules that carry it.
Cholesterol itself cannot dissolve in the bloodstream, and needs proteins to "carry" it around.
"Bad" cholesterol is that which is carried on a molecule called "LDL" (for "low-density
lipoprotein"), and which has the tendency to release cholesterol into the tissues, including the
vessel walls. A smaller molecule, "HDL" (for "high-density lipoprotein") is also called "good"
cholesterol because it can bring cholesterol back from the tissues to the liver. The higher the level
of HDL and the lower the level of LDL, the less likely it is someone will develop blockages (no
levels guarantee it, though!).
What is blood pressure?
Blood pressure is the rhythmic stretching of the arteries caused by the pressure of blood from the heart
during systole (contraction of atria and ventricle). Pressure is caused by the resistance exerted by the vessels in the
tissues.
The veins have zero pressure. Blood returns to the heart with the aid of muscular contraction, valves and
the lifting of the chest cavity during breathing. The kidney contributes to maintenance of blood pressure by
regulating blood volume. With age, the arterial wall become less elastic causing systolic pressure to rise as the heart
has to pump against a less compliant system.
Central control of blood pressure is integrated and regulated by diffuse neurons within a region of the medulla
oblongata.
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A blood pressure of 120/70 indicates the force of the heart beat during systole (contraction) is 120 mm of
mercury and the pressure in the arteries during diastole (resting) is 70 mm Hg.
140/90 is hypertension
100/70-80 is low systolic (result from poor nutrition or glandular disorders)
Blood Cells include Red, White and Platelets. All arise in bone marrow from stem cells.Hemophilia is an inherited
disease in which individuals lack the ability to clot and consequently bleed excessively.
Anemia occurs in individuals having low levels of hemoglobin or low numbers of red blood cells.
Leukemia is cancer of the bone marrow cells that produce leukocytes.
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The Respiratory System
Cell Respiration: is the means by which a cell makes energy that involves the exchange of O2 and CO2.
Animals need to obtain oxygen and glucose to get rid of carbon dioxide waste. How does the body exchange the
gases?
Respiratory system includes the lungs and the passageways that carry air to the lungs; nasal cavity,
pharynx (throat), larynx (voicebox), trachea (windpipe) and bronchi. Visceral pleura is membrane covering the
lung; parietal pleura is external to the visceral pleura and lines the thoracic cavity.
Functions: gas exchange, O2 in, CO2 out.

Gas exchange involves breathing, the transport of gases and supplying gases to tissues.

The transport of gases involves diffusion into red blood cells.

Gases are transported within the circulatory system to all tissues in the body attached to the protein
hemoglobin. Hemoglobin has a large affinity for O2.

Gas exchange requires a moist body surface. All respiratory surfaces are moist and thin. Gases must be
dissolved in water before they can diffuse in or out.
Environmental adaptations
A. Earthworms are skin breathers, found in moist env. Gas is exchanged from environment into the cells.
B. Gills evolved in most aquatic animals. The increase the respiratory surface by folding and by projecting
away from the body surface. They are aided by a circulatory system.
C. Trachea evolved in insects, they are specialized breathing tubes. The tubes bring external gases directly
to the inner cells, without the aid of a circulatory system.
D. Lungs evolved in most terrestrial vertebrates, they are composed of branched tubes ending in tiny
internal sacs, lined with moist epithelium.
Inhalation is breathing in O2 while exhalation is breathing out CO2. The thoracic cavity (rib cage) enlarges
due to contraction of rib muscles and diaphragm muscles, causing air to move inside the respiratory passageways.
All of the surfaces are lined with moist epithelium. The lungs increase in size, this causes low pressure inside the
lungs, so air moves in to balance the gradient in pressure. Air passes through the nasal cavity, pharynx, trachea,
bronchi, bronchioles and finally reaching the alveolus in the lungs at the tip of the bronchioles. The capillary beds
are interspersed with the alveoli. Here O2 and CO2 diffuse based on their concentration gradients.
Respiratory Adaptations
Life at high altitude, is colder and has less O2. People born in and adapted to high altitudes have relatively large
hearts, more red blood cells and greater hemoglobin levels.
After a short time, individuals living in lower altitudes acclimate to higher altitudes. Faster heart rate and larger
capillary diameter are replaced over time with deeper and more rapid rates of breathing, more capillaries, and higher
numbers of red blood cells and higher levels of hemoglobin.
Animals like birds are capable of exchanging gases from environments that are inhospitable for humans. Mt Everest
is 28000 feet in altitude, man can not survive because of the cold and low O 2 content. Birds have more efficient
lungs, their hemoglobin has a higher affinity for oxygen, they have larger numbers of capillaries and proteins in their
muscles hold oxygen.
Smoking
The epithelial lining of the lungs traps and removes particles (pollutants, asbestos, tobacco smoke) Tobacco smoke
irritate epithelial cells and destroy the function of cilia and macrophages. This allows more toxins to reach the lung
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alveoli. Coughing is the systems attempt to clean the lungs. Smokers often get emphysema, the alveoli become
brittle and eventually rupture. The leading cause of death among smokers is cardiovascular disease. Smoking
negatively affect prenatal development and development of infants and children.
Emphysema and chronic bronchitis together comprise chronic obstructive pulmonary disease
Emphysema is a condition in which there is over-inflation of structures in the lungs known as alveoli or air sacs.
Damage to the air sacs is irreversible and results in permanent "holes" in the tissues
The lungs also lose their elasticity, which is important to keep airways open. The patient experiences great difficulty
exhaling.
Emphysema doesn't develop suddenly, it comes on very gradually. Years of exposure to the irritation of cigarette
smoke usually precede the development of emphysema.
Chronic bronchitis: when airways of the lungs become inflamed and clogged with mucus, often in response to
environmental irritants.
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The Digestive System
Digestive System includes the digestive tract, a long tube that begins in the mouth and ends at the anus.
Along the way there is a stomach, glands (salivary, liver, pancrease) and large and small intestine. Food is digested
by mastication, churning and enzymatic action then absorbed by the body through capillaries. The tube is composed
of muscular tissue with epithelial tissue (mucosa) on the inside and connective tissue (serosa) on the outside. The
loose connective tissue houses the nervous tissue and supply of blood vessels. Food is pushed along the digestive
tract by a series of wave like motions, called peristalsis. The nervous tissue coordinates the peristaltic motions. The
mucosa is highly specialized. It has many folds (called villi) that increase the absorption area. The internal space of
the digestive tract is the lumen.
Function of the digestive system is to get food into a usable form for the body and rid the body of waste.
Macromolecules are broken into monomers using ENZYMES. Monomer are absorbed into blood by the small
intestine.
The total digestive process takes about 5-6 hrs.
The steps in digestion are:
The human digestive system consists of an alimentary canal (tube) and accessory glands.
The alimentary canal includes the mouth, oral cavity, tongue, pharynx, esophagus, stomach, small intestine,
large intestine, rectum and anus. Food is moved through the alimentary canal by wavelike contractions of smooth
muscles.
The glands include the salivary glands, pancreas and liver. They secrete digestive enzymes into the cavities.
Ingestion: Mechanical processing begins in the mouth with chewing and lubrication that involves mucous
and salivary secretions. Aided by teeth food is crushed, shredded, ground into smaller parts. Salivary juices contain
lubricants, buffers, antibacterial agents, and digestive enzyme (amylase). Amylase hydrolyzes starch. The pharynx
when we are not eating is open to the larynx and the trachea used for breathing, when we swallow, the trachea is
closed off and the food is directed to the esophagus. The esophagus is merely a muscular tube that transports food
from the mouth to the stomach.
Digestion: Food is stored in the stomach and broken down with acid and enzymes. The inner surface of the
stomach is highly folded and has pits that terminate into gastric glands. Chemical digestion in the stomach is aided
by contractions of smooth muscle in the stomach wall. Protein digestion into smaller polypeptides occurs by the
action of the enzyme pepsin. Gastric Juices include a) mucus protects the stomach lining and lubricates b)
hydrochloric acid which provides the proper pH for the action of pepsin, it also activates pepsin and it helps to
hydrolyze proteins. Hydrochloric acid has a pH of 1.
Gastric activity is initiated by a nervous signal from the brain (after seeing, smelling or tasting food) which
stimulates the secretion of gastrin (a gastric gland hormone).
Absorption. Once molecules have been broken down into small molecules they can enter the cells of the body.
Elimination is the release of undigested material
Health Watch
Heartburn is caused by an overflow of the stomach contents into the esophagus.
Ulcers are open sores on the stomach lining. Leads to pain in the abdomen associated with eating. The major cause
of ulcers is the bacterium Helicobacter pylori.
Ulcers are also caused by nonsteroidal anti-inflammatory drugs, such as aspirin and ibuprofen.
The major organ of chemical digestion and nutrient absorption is the small intestine. The liver and gallbladder
makes secretions into the small intestine.
liver releases bile which aids in the breakdown of fats
gallbladder stores the bile until it is needed
pancrease makes enzymes an dbicarbonate ions to neutralize the acid chyme and raise its pH.
The major site of nutrient absorption occurs in the small intestine. The design of the small intestine provides a
large surface area. The tubing alone is 6 meters long, with several layers of folding. The wall is folded into circular
pleats. The pleats contain projections (villi) of cells and the cells have further projections (microvilli). The villi
contain capillaries and lymph ducts. Nutrients diffuse from intestine chamber to blood. Nutrient enriched blood
passes first to the liver. The liver processes or stores the nutrients (glycogen).
The large intestine reclaims water. It is 1.5 m long. Prokaryotes living in the large intestine include E. coli and
produce vitamins that humans cannot make.
21
Undigested material (fiber) is compacted by peristalsis and stored in the rectum until defecated.
The appendix is a gland at the top of the large intestine that has an immune function. Appendix can become
infected because of irritation or because its opening is blocked by undigested foods
The four macromolecules: Carbohydrates, Proteins, Lipids and Nucleic Acids. Once carbohydrates and proteins
are broken down enough they move out of the small intestine through the associated capillary bed. The veins from
these capillaries go to the liver. The nutrients are further refined in the liver then through veins they go on to the
heart. The heart now takes them to all tissues in the body.
Diet and Digestive Adaptations
1. Herbivores and omnivores have longer alimentary canals than do carnivores (to allow more time and surface area
for digesting plant material.
2) Most herbivores rely on the cellulose-digesting enzymes of prokaryotes and protests. Populations of these
organisms are housed in parts of the animals digestive track.
Nutrition
A Healthy Diet should
a. Fuel the body
b. Provide raw material for synthesis of needed molecules
c. Provide essential nutrient an animal cannot make. Of the 20 amino acids needed our bodies
make 11 but 9 must be obtained in the diet. 13 vitamins must be obtained in the diet. Fats are essential to
diet for the manufacture and uptake of fat soluable vitamins. Chemicals other than carbon, hydrogen,
oxygen and nitrogen are considered minerals, they too must be obtained in diet. Fiber is essential for
proper elimination of waste.
Identify each organ and its function
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Control of the Internal Environment in Mammals
Ectotherms warm themselves by absorbing heat from the surroundings
Includes: Amphibians, fish, reptiles
Endotherms derive most of their body heat from their own metabolism.
Includes: Birds and mammals
Thermoregulation is the control of temperature. External temperature fluctuates how does the body
adjust?
a.
Mammals change their metabolic rates to generate heat. Muscle movement (moving around or shivering)
generates additional heat
b.
Increase the thickness of the skin or of hair. Hair and fur have insulating power.
c.
Changes in blood flow to or from the changes the temperature of the skin and subsequent heat loss by
convection.
d.
Cooling occurs by evaporation during sweating or panting
e.
Relocating to a different physical location
f.
Bathing
Osmoregulation is the control of the concentration of water and dissolved solutes.
Diffusion the movement of solutes from a high concentration to a low concentration Osmosis the
movement of water from a high concentration to a low concentration
Animal cells would lyse if there was a net gain in water and would die from a net loss (dehydration).
Animals lose water in urine, feces, perspiration, evaporation and breath.
Animals gain water in food and drink
Excretion is the disposal of nitrogen – containing waste
Nitrogen containing wastes come mostly from the breakdown of proteins and nucleic acids
The forms of Nitrogenous wastes:
Aquatic animals secrete ammonia (the most toxic form)
Terresterial animals convert ammonia to less toxic forms:
 Humans secrete urea,
 Birds, Insects, reptile and snails secrete uric acid (its more concentrated therefore conserves water
Urinary system is the excretory system plays a role in osmoregulation and excretion of nitrogen wastes.
This system functions in the elimination of waste products from the blood through the formation of urine. The key
functions is excretion which involves filtration, reabsorption, secretion and excretion.
Four Organs in the Urinary System:
1. Kidneys: this is the processing center for the excretory system. Blood enters and leaves the kidney through
the renal artery and renal vein. The nephron is the fundamental unit of the kidney and excretory system.
Kidneys have several important functions, including the production of urine.
 maintain water balance by removing excess fluid from your body.
 remove waste products. Metabolism results in waste products that become toxic (poisonous) if they
are left to accumulate in your body. The kidney filters the blood to remove waste products such as urea
and creatinine.
 Kidneys maintain normal blood chemistry. Kidneys make sure you keep the right amounts of
potassium, sodium, phosphorus, calcium, bicarbonate, magnesium and chloride and get rid of those
you don't need.
Kidneys also make three important hormones - renin, erythropoietin and calcitriol:
 Renin helps regulate your blood pressure.
 Erythropoietin (er-ree-throw-po-e-ten) helps maintain the right amount of blood in your body
(blood volume) by simulating your bone marrow to make more red blood cells.
 Calcitriol helps your body absorb calcium from the food you eat.
2.
3.
4.
Ureter: this is the conduit that transports urine from the kidney to the bladder
Urinary bladder: this is the site for storage of urine
Urethra this is the conduit that transports urine from the bladder during excretion
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Filtration Process
The kidney has thousands of blood filtering units called nephrons.
The nephrons are composed of tubules and associated blood vessels. The nephron extracts and refines the filtrate
then releases the urine. The blood filtering region is the Bowman’s capsule and the filtrate refinery includes the
proximal tubule, loop of Henle and distal tubule.
The blood vessels of the nephron include a ball of capillaries called glomerus. In the glomerus blood
pressure forces water and solutes out of the blood and into the tubule and second set of vessels are the capillaries
surrounding the loop of Henle. The second set helps refine the filtrate.
Filtration region is Bowmans Capsule: water and small molecules are forced by blood pressure through
capillary walls into the nephron tubule.
Reabsorption occurs in the Loop of Henle: water and solutes still valuable to the body are reclaimed from the
filtrate. NaCl and H2O are reabsorbed by the filtrate in the proximal and distal tubules.
 Organisms living in dry environments must reabsorb water more efficiently. In this case the Loop of Henle
is extra long.
 The reabsorption of water is under hormonal control (antidiuretic hormone is produced by the
hypothalamus and released from the pituitary.
Secretion: excess ions, drugs and toxins are secreted from the blood into the nephron tubule
Excretion: urine passes from the kidney to the outside by way of the urinary bladder and urethra.
Kidney failure: Failing kidneys cannot get rid of excess fluid. Urine output goes down causing a rise in blood
pressure, shortness of breath and swelling in many areas of the body. Waste products accumulate. The buildup of
waster products in the body results in uremia. Uremia is "urine in the blood." Uremia affects all the systems in the
body When drugs and diet are no longer effective, patients need treatment to do the work of their failed kidneys. If
you lose close to 90% of kidney function, they need to start dialysis or have a kidney transplant to stay alive.
Dialysis means "to clean the blood." Dialysis removes the waste products and excess water from the body,
and stabilizes blood chemistry.
IDENTIFY ALL ORGANS AND KNOW THE FUNCTIONS
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Reproductive System
Reproductive System functions in the perpetuation of the species (making of offspring). Two separate
systems for making separate but compatible gametes, male and female. Gametes are made in an unfinished form
called:
oocytes in women and stored in the ovaries nurtured in a complex of cells and fluids call follicles. Once a
month an oocyte matures into an egg and travels down the uterine (fallopian tube) in a process called ovulation. At
birth an ovary has all the follicles (the storage unit for the Oocyte, includes Oocyte and nurturing cellular
environment) a women will ever have approximately 40,000-400,000. Only several hundred will release eggs, once
every 28 days. Oogenesis is the process by which the egg is made from the germ cell. The diploid germ cell (oocyte)
undergoes 2 meiotic divisions to produce 4 haploid cells. Only one becomes the egg the other three are the polar
bodies. FSH (follicle stimulating hormone) from the pituitary gland stimulates one dormant follicle to develop. LH
(leutenizing hormone) from the pituitary gland, signals the egg to leave the ovary. LH causes the secretion of
estrogen and progesterone to prepare the lining for implanting a fertilized egg.
The gonadotropin hormones (FSH, LH) are regulated by the hypothalamus.
Spermatocytes in men and stored in testes then transferred to the epididymis where they mature. The male
releases some 250 million sperm per ejaculation which travels from the epididymis through the vas deferens and
finally the urethra where it is ejaculated into the vagina. Sperm are made by spermatogenesis the diploid germ cell
(spermatocytes) undergo two meiotic divisions to produce 4 sperm cells, equal in size and potency.
The Female Menstral Cycle
Day 1-7: Bleeding (low estrogen and progesterone) due to a breakdown of the endometrium. Preovulatory
phase of the cycle.
Between 7-14. Following bleeding: Regrowth of the endometrium. Estrogen (EST) levels peak.
Day 14:Ovulation (this is the point pregnancy can occur): FSH and LH levels are high. They are required
for ovulation. The follicle develops in the corpus luteum. Preparing for fertilization and implantation the lining
secretes EST and PRO. These high levels of EST and PRO inhibit the initiation of new menstral cycles.
If fertilization and implantation does not occur, the corpus luteum disintegrates. Levels of estrogen and
progesterone decrease. FSH and LH levels increase and new ovarian and menstral cycles are initiatied.
Should sperm meet egg there is fertilization. Estrogen and progesterone remain high. The corpus luteum is
maintained because of the secretions of the hormone gonadotropin (HCG) by the developing embryo. Gradually a
placenta replaces the corpus luteum. A zygote forms.
The Male Cycle
During Sexual Arousal: Erectile tissue in the penis swells with blood, essential for insertion into the vagina.
The penis and the clitoris in female vaginal anatomy are homologous structures. Both have glands that are richly
supplied with nerve ending and foreskin that covers the glands.
Ejaculation. 1) A peak in sexual arousal, causes muscles in the epididymis, seminal vesicles, prostate gland
and vas deferens to contract. Forcing sperm and secretions into the vas deferens. 2) The sphincter muscle opens and
the strong muscular contractions force the semen along the urethra and out of the penis.
Sperm and androgen production are also under the control FSH and LH hormones from the pituitary, FSH
increases production of sperm by testes. LH promotes secretion of androgens, mainly testosterone.
Spermatogenesis: Hundreds of millions of sperm is produced daily from puberty onward. 4 sperm cells are
derived from each Oocyte
Semen consists of sperm cells and secretions from glands. 200-500 million sperm in one teaspoon of semen
discharged during a typical ejaculation. The prostate gland secretes a milky alkaline fluid that neutralizes the acidity
of male and female reproductive tracts.
The Pathway Sperm Travels
Testes  Epididymis (storage until develop motility and fertilizing ability)  vas deferens  seminal vesicle 
ejaculatory ducts  urethra
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Principles of Embryonic Development
Embryonic development involves cell division, differentiation, and morphogenesis.

Cell division results in an increase in the number of cells. All the cells result from mitotic divisions
beginning with the zygote.
Fertilization is the fusion of two haploid cells. It results in a zygote. The zygote triggers embryonic
development.

Differentiation is the development of specialized cells that are organized into tissues and organs. This
differentiation is controlled by the cell's expression of different genes brought on by its contact with the
environment.

Morphogenesis includes the physical processes that give shape to the animal's body and organs.
Question: How do we go from a single diploid cell at fertilization to an organism that has a variety of cell,
tissue and organ types?
Epigenesis is the belief that the form of an embryo gradually develops from a formless egg (proposed by the Greek
philosopher Aristotle).
Modern biologists have found that the organism's development is mostly determined by the zygote's genome and the
organization of the egg's cytoplasm. As the zygote undergoes cleavage, the cytoplasm is compartmentalized causing
the nuclei of the different cells to be exposed to different cytoplasmic environments. These different cytoplasmic
environments result in the expression of different genes in different cells. Inherited traits then emerge, in an orderly
fashion, in space and time by mechanisms controlling gene expression.
The steps in the fertilization process are as follows:

The Acrosomal Reaction: This reaction is caused by a discharge of hydrolytic enzymes from the
arcosome of the sperm cell. When the head of the sperm contacts the egg the enzymes are released from a
vesicle. This allows the arcosomal process to elongate and penetrate the jelly coat of the egg. The protein
coating the tip will attach to the exact receptors on the egg's vitelline layer to ensure it is the correct species
of sperm. The enzymes continue to digest the membrane allowing the tip to reach the plasma membrane of
the egg. The two membranes fuse, allowing the sperm's nucleus to enter the egg. A quick depolarization
then occurs locking out all other sperm from the egg.

The Cortical Reaction: The fusion of the sperm and egg membranes stimulates a series of changes in the
egg's cortex. The egg-sperm fusion causes a signal transduction pathway involving a G- protein to stimulate
the release of Ca2+from the egg's endoplasmic reticulum. The Calcium acts as a second messenger and
results in a increase in calcium in target areas. Eventually the zygote membrane area will swell and
become hard forming a fertilization membrane. This membrane will prevent additional sperm from entering
the egg.

Activation of the Egg: The sharp rise in cytoplasmic calcium also incites metabolic changes that activates
the egg. Cellular respiration and protein synthesis increase; cytoplasmic pH becomes more basic due to a
loss of H+ ; the sperm nucleus swells and merges with the egg nucleus to form the zygote and DNA
replication begins with the first division occurring in about 90 minutes.
Post-Fertilization Events

Cleavage: is a succession of rapid mitotic cell divisions following fertilization and produces a multi
cellular embryo, the blastula. During cleavage the S and M stages of the cell cycle occur, while the G 1 and
G2 phase are skipped. Very little gene transcription occurs causing very little growth in the embryo. A
polarity results gradient in the concentration of cellular components like mRNA, proteins, and yolk. The
vegetal pole of the egg has the highest concentration of yolk. The animal pole has the lowest concentration
and is the area where polar bodies bud off of the cell. The animal pole marks where the most anterior part
of the animal will form. The animal hemisphere is gray due to the presence of the pigment melanin. The
vegetal hemisphere is slightly yellow due to the yellow yolk. Cleavage in the animal hemisphere is more
rapid than in the vegetal hemisphere. If there is little yolk in the vegetal hemisphere cleavage will proceed
equally. The first two cleavage divisions are vertical and divide the embryo into 4 cells. The third cleavage
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plane is horizontal and produces an 8 cell embryo with two levels. Deuterostome cleavage forms 2 tiers of
cells one exactly above the other. Protostome cleavage the upper tier of cell align directly over the grooves
of the lower tier. Continual cleavage produces a solid ball of cells called the morula. A fluid filled cavity,
called the blastocoel develops within the morula forming a hollow ball of cells called the blastula.
Gastrulation: rearranges the blastula to form a three-layered embryo with a primitive gut. The three layers produced
by gastrulation are embryonic tissues called embryonic germ layers:
1.
Ectoderm is the outer layer of the gastrula. It produces the nervous system, epidermis, epidermal glands,
inner ear, and eye lens.
2.
Endoderm produces the lining of the digestive tract lining, liver, pancreas, and lungs.
3.
Mesoderm partially fills the space between the ecto and endoderm. The kidneys, coelomic lining, muscles,
skeleton, gonads, heart, muscles, inner layer of the skin and most other organs develop from the mesoderm.
These three germ layers will eventually develop into all parts of the adult animal.
Gastrulation during frog development begins with a small crease on the blastula where the blastopore will eventually
form. Invagination occurs due to a cluster of cells burrowing inward. This process produces a dorsal lip where the
gray crescent was located on the zygote. Involution then occurs. This is the process where cells on the surface roll
up and move into the embryo's interior away from the blastopore. The archenteron (primitive gut) forms within
the endoderm.
Organogenesis: forms the organs of the animal body from the three embryonic layers. The first evidence of
organogenesis is morphogentic changes (folds, splits, condensation of cells) that occur in the layered embryonic
tissues.
Not for Bio3: The neural tube and notochord are the first organs to develop in frogs and other chordates. The
ectoderm above the beginning notochord thickens to form the neural plate that sinks below the embryo's surface and
rolls itself into a neural tube that will become the brain and spinal cord. The notochord stretches the embryo
lengthwise and forms the core around witch the mesoderm cells will develop the muscles of the axial skeleton. As
organogenesis continues, other organs and tissues develop from the embryonic germ layers.
In the organ systems that follow identify all
organs and their function. In one image
there are two organ systems.
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