Download Saint Paul College Science T. Priscilla Alpízar Study guide answers

Saint Paul College
Science
T. Priscilla Alpízar
STUDY GUIDE ANSWERS: ANIMAL ORGANIZATION
Tissues
1. What is homeostasis?
It is the process by which an organism maintains its internal environment within the narrow
range of conditions necessary for optimal cell functioning.
2. Explain the how the animal body is organized. Your explanation must include the definition
for: cells, tissues, organs, and organ systems; and an example for each.
Cells are the basic unit of all living organisms, like heart muscle cells. When several cells act
together to perform a particular function, they form a tissue (like muscular tissue). Tissues
build organs, structures that can perform very complex functions (a heart for example).
Organs are organized into organ systems, which are groups of organs that function in a
coordinated manner (like the circulatory system).
3. Which are the four types of animal tissues?
Epithelial, connective, muscle and nerve tissues.
4. Create a summary about the four types of animal tissues. Your summary must include:
 The function or functions of each type of tissue.
 The composition of each type of tissue (cells, layers, etc.).
 Examples of each type of tissue.
 A drawing of each type of tissue (it can be of one of the examples), with their parts
labeled.
 The different kinds inside each type of tissue and their differences.
Animal tissues
 Epithelial tissue is the one in charge
of covering the entire outside of the
body and lining its inner cavities. It
consists of a basal lamina (collagen
and fibrous proteins) and densely
packed epithelial cells. One example
of epithelial tissue is the one that
makes up skin. There are two types:
simple (only one cell thick) and stratified (several cells thick).
 Connective tissue supports and binds other
tissues. It is composed of cells embedded in a
matrix of extracellular substances, like collagen.
There are three types: loose (thick fluid with
scattered cells that secrete protein fibers and
collagen), fibrous (densely packed collagen fibers
in a parallel arrangement), and specialized (a
diverse group of tissue). Some examples are:


membranes, tendons, ligaments, cartilage, blood, bone, lymph, and adipose tissue.
Muscle tissue is in charge of movement, and consists of
muscle cells. There are three types: skeletal (under
voluntary control, moves the skeleton), cardiac
(involuntary control, stimulates cardiac muscle cells to
contract), and smooth (produces slow and sustained
involuntary contractions).
Nerve tissue is in charge of sensing and
responding to the world. It is found in the
brain, the spinal cord, and the nerves. It is
composed of two types of cells: neurons and
glial cells.
5. What are glands? Explain the differences between exocrine and endocrine glands.
Glands are cells or group of cells specialized to secrete large quantities of substances outside
the cells. Exocrine glands are those that secrete non-hormonal substances into a body cavity
using a duct; while endocrine glands secrete hormones into nearby capillaries because they
lack ducts.
Circulatory system
1. Name the three main parts every circulatory system must have.
A fluid (blood), a system of channels (blood vessels), and a pump (heart).
2. Explain the difference between open and closed circulatory systems, and give one example of
animal that has each.
Open circulatory systems have several simple hearts, a network of blood vessels and a
hemocoel (large open space within the body). Tissues and organs are bathed in blood directly
in the hemocoel. Closed circulatory systems confine blood to the heart and blood vessels.
Examples of animals with an open circulatory system are arthropods and some mollusks; while
those with closed ones are vertebrates.
3. What are the functions of the circulatory system?
 Transport oxygen from the lungs or gills to the tissues, and transport carbon dioxide from
the tissues to the lungs or gills.
 Distribute nutrients from the digestive system to all body cells.
 Transport waste products and toxic substances to the liver (detoxification) and kidneys
(excretion).
 Distribute hormones from the glands and organs that produce them to the tissues upon
which they act.
 Regulate body temperature, which is achieved partly by adjustments in blood flow.
 Prevent blood loss by means of the clotting mechanism.
 Protect the body from bacteria and viruses by circulating antibodies and white blood
cells.
4. What is the cardiac cycle? Explain how it works.
The cardiac cycle is the process related to blood flow or movement. It has several steps. First,
the atria contract and, this contraction, forces blood into the ventricles. Second, the ventricles
contract, forcing the blood through arteries to the lungs and the rest of the body. Finally, the
heart relaxes, and the cycle starts again.
5. What are the five types of blood vessels? Explain their differences in size and function.
The five types of blood vessels are: arteries, arterioles, capillaries, venules, and veins. Arteries
and veins are the wider ones; and capillaries the thinnest ones. Arteries carry blood away from
the heart. Capillaries are microscopic vessels that allow the exchange of materials between
the blood and the fluid bathing body cells. Veins carry blood back to the heart
6. Name the two components of blood.
Plasma and cellular components (red and white blood cells, and platelets).
7. What is the lymph system? What is the relationship between it and the circulatory system?
The lymph system is the one that removes excess interstitial fluid that leaks through blood
capillary walls.
Respiratory system
1. What are the three evolutionary adaptations needed for gas exchange?
The three requirements are that: (1) respiratory surfaces must remain moist (gases must be
dissolved in water to diffuse into or out of our cells), (2) respiratory surfaces must be very thin
(facilitate diffusion), and (3) the respiratory system must have a large surface area in contact
with the environment to allow adequate gas exchange.
2. Explain how gas exchange works in mammals.
In mammals, gases move in and out of the lungs by bulk flow. Oxygen moves into the lungs,
and carbon dioxide leaves them. Inside the lungs, there is a gas exchange (oxygen and carbon
dioxide) by diffusion. Oxygenated blood transports oxygen dissolved in it, which is transported
by bulk flow. When oxygenated blood reaches tissues with a small amount of oxygen, there’s
an exchange of oxygen with carbon dioxide by diffusion. Carbon dioxide travels back to the
lungs using deoxygenated blood as a carrier, and is expelled out of the body when we exhale.
3. Explain the path taken by air to reach the blood stream. Your answer must include the parts of
the respiratory system.
Air enters the nasal cavity or mouth and passes through the pharynx and the larynx into the
trachea. The epiglottis prevents food from going down the trachea. The trachea splits into two
bronchi, which lead into the lungs. Each bronchus branches into numerous bronchioles that
conduct air into microscopic alveoli, enmeshed in capillaries, where gas exchange occurs.
Digestive system
1. What’s the main function of the digestive system?
Its function is to convert the complex molecules of the animal and plant bodies that have been
eaten into simpler molecules that can be used.
2. Name the five tasks that must be accomplished by all digestive systems.
Ingestion, mechanical and chemical breakdown of food, absorption, and elimination of wastes.
3. Explain the path taken by the food when we eat, naming all the organs it passes through and
their function.
Food first needs to pass through the mouth, where it’s physically broken down by chewing and
the beginning of chemical ingestion (due to saliva). Then, the esophagus conducts food to the
stomach. In this organ, food is broken down into smaller particles and protein digestion
begins. Chyme (or broken food) moves into the small intestine, where it is neutralized using
sodium bicarbonate by the pancreas. Due to secretions of the pancreas, liver, and intestine;
the breakdown of proteins, fats, and carbohydrates is completed. Then, in the small intestine,
the simple molecular products of digestion are absorbed into the bloodstream for distribution
to the body cells. The large intestine absorbs water and converts indigestible material to feces,
which are stored in the rectum and eliminated through the anus.
Urinary system
1. Which are the basic processes made by the urinary system?
Filtration of blood or interstitial fluid to remove water and small dissolved molecules, selective
reabsorption of nutrients, excretion of excess water, nutrients, and dissolved wastes.
2. Why is the urinary system important to maintain the body’s homeostasis?
Because it helps maintain the chemical composition of the blood and extracellular fluid within
the range required for metabolism.
3. Name the four main parts of the urinary system and their functions.
Kidneys (produce urine), ureters (conduct urine to the bladder), bladder (store urine, trigger
urination), and urethra (urine passes out of the body through it).
4. What are the three types of nitrogenous wastes and which animals have each type?
Ammonia (fish), urea (terrestrial vertebrates), uric acid (birds, reptiles, insects).
Immune system
1. Which are the three major lines of defense present in vertebrates and the two in
invertebrates? Explain each line.
Vertebrates: nonspecific external barriers, nonspecific internal defenses, and specific internal
defenses.
Invertebrates: nonspecific external barriers and internal defenses.
2. Explain what are allergies?
Immune responses to normally harmless foreign substances.
Endocrine system
1. What’s the main function of the endocrine system?
It controls physiological processes.
2. How do cells communicate? Explain each type of communication and give an example for
each.
Direct communication is when there’s direct movement through gap junctions linking cytosol
of adjacent cells, like when ions flow between cardiac muscle cells. Paracrine communication
happens by diffusion through interstitial fluid to nearby cells bearing receptors, it is used by
prostaglandins. Endocrine communication is when chemical messengers are carried in the
bloodstream to near or distant cells bearing receptors, like it happens with insulin. Synaptic
communication is when there’s diffusion form a neuron across a narrow space to a cell bearing
receptors, like it happens with acetylcholine.
3. Name five endocrine glands and their functions.
Hypothalamus (produces AND and oxytocin, regulates hormones for anterior pituitary),
pancreas (secretes insulin and glucagon), thyroid gland (secretes thyroxine and calcitonin),
pineal gland (produces melatonin), kidneys (produce erythropoietin).
Nervous system
1. What are neurons? Name their functions and parts.
Neurons are nerve cells, and they are in charge of receiving information from the internal or
external environment or from other neurons, processing it, conducting the electrical signal,
and communicating with other cells. They have several parts: synaptic terminals, dendrites,
cell body, axon, and synaptic terminals.
2. Which are the four basic operations performed by the nervous system?
Determine the type of a stimulus, determine and signal the intensity of a stimulus, integrate
information from many sources, and initiate and direct appropriate responses.
3. Summarize the organization of the nervous system. What’s the difference between the central
and the peripheral nervous system?
The nervous system divides in central nervous system (CNS) and peripheral nervous system
(PNS). The CNS, receives and processes information and initiates action; while the PNS
transmits signals between the CNS and the rest of the body. The CNS is made of the brain and
the spinal cord. The PNS is composed of motor neurons and sensory neurons.
4. How is neural activity transmitted?
Using electrical voltages across neurons’ membranes.
Muscular system
1. Name the functions for each type of muscle.
Smooth muscle controls movement of substances through hollow organs and tubes. Cardiac
muscle pumps blood. Skeletal muscle moves the skeleton.
2. Explain how muscle contraction works.
When muscles contract, thin filaments move aside and expose binding sites on the actin.
When the sites are exposed, myosin heads bind the acting and link the thick and thin
filaments. Using ATP, the myosin heads bend, release, and reattach farther along the thin
filament.
Skeletal system
1. Which are the three types of skeletons found in animals, and how are they different?
Hydrostatic (fluid-filled sac), exoskeleton (encase the body), and endoskeleton (internal).
2. Which are the functions of the skeleton?
Supports the body, protects internal organs, locomotion, red and white blood cells and
platelets production, stores calcium and phosphorus, sensory transduction.
Reproductive system
1. Name the main functions of the male and female reproductive system?
Produce sex cells (both), inseminate female (male), and nurture developing offspring (female).
2. Explain the function of the main organs (testes, epididymis, vas deferens, urethra, penis,
seminal vesicles, and prostate gland) of the male reproductive tract.
 Testes: produce sperm and testosterone.
 Epididymis: store sperm.
 Vas deferens: conduct sperm from testes to penis.
 Urethra: conducts semen from vas deferens and urine from urinary bladder to the tip of
the penis.
 Penis: deposits sperm in female reproductive tract.
 Seminal vesicles: secrete fluid into semen.
 Prostate gland: secretes fluid into semen .
3. Explain the function of the main organs (ovaries, fimbria, uterine tubes, uterus, cervix, vagina)
of the female reproductive tract.
 Ovaries: produce eggs, estrogen, and progesterone.
 Fimbria: bear cilia that sweep egg into oviduct.
 Uterine tubes: conduct egg to uterus, site of fertilization.
 Uterus: muscular chamber where fetus develops.
 Cervix: closes off lower end of uterus during pregnancy.
 Vagina: receptacle for semen, birth canal.
4. Name five contraceptive techniques and explain how they work.
Birth control pill, male condom, sponge, vaginal ring, spermicide.