Download The Digestive System:

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The Digestive System:
p977-984

Definition:
o A collection of organs that break down food into energy that can be used in cells.

List of Main Organs/Structures/Tissues:
o Mouth
o Stomach
o Esophagus
o Gall Bladder
o Liver
o Pancreas

Examples of Two Main Organs/Structures:
o Stomach:
 A muscular sac that mechanically processes food into chyme.
 Produces gastric juice that contains pepsin and HCl
 Begins the chemical digestion of proteins.
 Produces a protective layer of mucus, so it does not digest itself.
o Small Intestine:
 The pancreas, liver, and gall bladder excrete into the small intestine.
 A long, narrow tube in which most digestion takes place.
 All absorption occurs here.
 The inside is lined with villi.

Smallest Functional Unit:
o Villi:
 Small finger-like projections, covered with epithelial cells, which absorb nutrients.
 Increases the surface area of the inside of the small intestine.
 High surface area increases efficiency of absorption.
 Capillaries inside transfer the digested nutrients to the blood.

How the Organ System Maintains Homeostasis:
o Provides all body cells with the essential nutrients they need in order to survive.

An Example of Departure from Homeostasis:
o Type 1 Diabetes:
 Causes:
 Cells require insulin to take in sugars for energy.
 Pancreas cells are attacked by the immune system.
 Symptoms:
 Insulin production slows.
 Sugars are excreted with the urine, and water follows.
 The body breaks down fat for energy and the blood becomes acidic.
 Changes in pH and fluid balance kills cells all over the body.
o Small Intestine
o Large Intestine
o Rectum/Anus
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The Nervous System:
p874-879, 885-894

Definition:
o A physically connected network of cells, tissues, and organs that controls thoughts, movements,
and simpler life processes.

List of Main Organs/Structures/Tissues:
o Brain
o Nerves
o Spinal Cord

Examples of Two Main Organs/Structures:
o Brain:
 The central organ of the nervous system
 Made-up of three main structures: cerebrum, cerebral cortex, and brainstem
 Attached (at its base) to the spinal cord
o Spinal Cord:
 Ropelike bundle of neurons about as wide as your thumb
 Connects the brain to other parts of the body (via neurons)
 Controls involuntary movements called reflexes

Smallest Functional Unit:
o Neurons:
 A specialized cell that stores information and carries messages within the nervous system
and between other organ systems.
 Are made of three parts:
 Cell body:
o Contains the nucleus and organelles
 Dendrites:
o Branchlike extensions that receive messages from neighboring cells
 Axon:
o A long extension of the cell that carries electrical messages away from the
cell body.

How the Organ System Maintains Homeostasis:
o Reflexes prevent injury or harm to the body by allowing quick, involuntary, responses to stimuli.
o Keeps certain areas of the brain active with appropriate amounts of neurotransmitters (chemicals)

An Example of Departure from Homeostasis:
o Depression:
 Causes:
 Low amounts of the neurotransmitter serotonin in the brain.
 Symptoms:
 Extended periods of intense sadness, inability to sleep, and feelings of
helplessness.
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The Endocrine System:
p874-875, 896-901

Definition:
o A collection of physically disconnected organs that helps to control growth, development, and
responses to the environment.

List of Main Organs/Structures/Tissues:
o Glands:
o Hypothalamus
o Pituitary

Examples of Two Main Organs/Structures:
o Hypothalamus:
 Small area in the middle of the brain
 Makes hormones that stimulate the pituitary gland to release hormones
 Stimulates the production of other hormones that control growth, reproduction and body
temperature
o Pituitary Gland:
 Small area in the middle of the brain
 Makes and releases hormones that control cell growth
 Stimulates other endocrine glands

Smallest Functional Unit:
o Glands:
 Small organs found in many places in the body
 Produce hormones
 Hormones are chemical signals made by the endocrine system

How the Organ System Maintains Homeostasis:
o Continually monitors and balances the levels of hormones in the body.

An Example of Departure from Homeostasis:
o Hypothyroidism:
 Causes:
 The thyroid does not produce enough of certain hormones.
 Symptoms:
 Weakness
 Sensitivity to cold
 Weight gain
 Depression
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The Respiratory System:
p910-912, 914-916

Definition:
o The body system in which gas exchange takes place

List of Main Organs/Structures/Tissues:
o Lungs
o Trachea

Examples of Two Main Organs/Structures:
o Lungs:
 Absorbs O2 and releases CO2
 Contain branch-like structures that help to absorb and release gases
o Trachea:
 Long structure made of soft tissue, reinforced with cartilage
 Divides into 2 bronchi (each branch goes into each lobe of the lungs)

Smallest Functional Unit:
o Alveoli:
 Small clusters of air sacs (look like small clusters of grapes)
 Gives lungs a HUGE surface area for absorbing O2 and releasing CO2

How the Organ System Maintains Homeostasis:
o Provides all cells with O2 and removes CO2 (a cell’s waste product).

An Example of Departure from Homeostasis:
o Asthma:
 Causes:
 Muscle spasms caused by constricted bronchioles.
 Triggered by allergens, stress, environmental factors, chemicals, or exercise.
 Symptoms:
 Shortness of breath
 Difficulty breathing
 Wheezing
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The Circulatory System:
p917-929

Definition:
o A body system that transports nutrients and wastes between various body tissues.

List of Main Organs/Structures/Tissues:
o Heart
o Veins
o Arteries
o Capillaries

Examples of Two Main Organs/Structures:
o Heart:
 A muscle in the chest that moves blood throughout the body.
 Has four chambers: the left and right atriums and the left and right ventricles.
 Has flaps of tissue called valves that prevent blood from flowing backward.
 The right side of the heart pumps blood to the lungs, and the left side pumps to all other
body tissues.
o Blood Vessels:
 Transportation networks for the blood.
 Includes:
 Arteries: transport blood away from the heart
 Veins: carry blood toward the heart.
 Capillaries: very thin walled allowing materials like oxygen to diffuse through them

Smallest Functional Unit:
o Blood:
 Red blood cells: carry oxygen to body cells and carry carbon dioxide away from cells.
 White blood cells: defend the body against infection and remove foreign material and dead
cells.
 Platelets: cell fragments that help form clots that control bleeding

How the Organ System Maintains Homeostasis:
o Circulates required substances and wastes away and toward the body cells.

An Example of Departure from Homeostasis:
o Atherosclerosis:
 Causes:
 Smoking
 Lack of exercise
 Excessive weight
 Long-term stress
 Symptoms:
 Blood flow is partially or fully blocked by sticky material, called plaque.
 High blood pressure
 Can lead to a heart attack, stroke, or kidney damage.
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The Immune System:
p945-954, 957-958

Definition:
o A body system that fights off infections and pathogens.

List of Main Organs/Structures/Tissues:
o Skin
o Circulatory System
o Cilia
o Lymphatic System

Examples of Two Main Organs/Structures:
o Cilia:
 Hair-like structures in the mucus membranes that produce sticky mucus.
 Trap invading pathogens so they cannot enter the body.
 Present in the openings to your body near your eyes, ears, nose, mouth, and excretory
organs.
o Circulatory System:
 Transports white blood cells and proteins such as antibodies and interferons throughout
the body.

Smallest Functional Unit:
o White blood cells:
 Find and kill pathogens that have gotten past the body’s external barriers.
 Ex) Phagocytes: surrounds, engulfs, and kills invading viruses, bacteria, and fungus.
 Ex) T-cells: destroy body cells that have been infected with pathogens.
 Ex) B-cells: produce antibodies that weaken the pathogens or clump them together.

How the Organ System Maintains Homeostasis:
o Detects and destroys pathogens that pose a threat to the homeostasis of many other body
conditions.

An Example of Departure from Homeostasis:
o Allergies:
 Causes:
 Allergens are proteins, called antigens, which cause an allergic reaction.
 Oversensitivity to a normally harmless antigen.
 Symptoms:
 A chemical called histamine and some white blood cells cause unnecessary
inflammation.
 Blood vessels become porous and blood leaks out of the circulatory system.
 Anaphylaxis occurs when inflammation tightens the airways.
 Can lead to asthma, sneezing, watery eyes, congestion, and rashes.
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The Excretory System:
p986-991

Definition:
o A body system that eliminates non-solid wastes through sweat, urine, and exhalation.

List of Main Organs/Structures/Tissues:
o Kidney
o Ureter
o Urinary bladder

Examples of Two Main Organs/Structures:
o Kidney:
 Organs that eliminate wastes by filtering and cleansing blood to produce urine.
 Maintain fluid and chemical balances in body by filtering water, salts, and other fluids.
 Hormones regulate kidney function.
o Urinary Bladder:
 A saclike organ that can store up to half a liter of urine at one time.
 Urine is released through the urethra into the outside environment.

Smallest Functional Unit:
o Nephron:
 The individual filtering unit of the kidney.
 Each kidney contains approximately 1 million nephrons.
 Blood enters the nephron through an artery where it is then filtered. Filtered blood leaves
the nephron and is returned into the circulatory system.

How the Organ System Maintains Homeostasis:
o Removes waste products from the blood
o Maintains electrolytes, pH, and fluid balances in the body

An Example of Departure from Homeostasis:
o Kidney Failure:
 Causes:
 Kidneys (including the nephrons) not properly working, or not working at all
 Symptom:
 Imbalance in electrolytes (sodium) disrupts the rhythm of the heart.
 Confusion and disorientation due to toxins building up and effecting neurons in the
brain.
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The Skeletal System:
p1000-1005

Definition:
o A body system that includes the bones and connective tissues that hold the bones together.

List of Main Organs/Structures/Tissues:
o Cartilage
o Examples of bones:
o Joint
o Clavicle
o Ligament
o Femur
o Humerus
o Vertebrae

Examples of Two Main Organs/Structures:
o Ligament:
 A long, flexible band of connective tissue that connects two bones across a joint.
o Cartilage:
 A flexible connective tissue that is found between two bones.
 Allows for smooth movements.

Smallest Functional Unit:
o Bone (osteocyte):
 Living tissue
 Supports, allows movement, and protects internal organs
 Form from cartilage that is hardened with calcium
 Grow from their ends where cartilage is located

How the Organ System Maintains Homeostasis:
o Deposits and removes calcium from bones.
o Serve as storage deposits for calcium (the body uses this calcium for other functions)

An Example of Departure from Homeostasis:
o Loss of bone density (osteoperosis):
 Causes:
 Calcium is lost (removed) from the bone to be used in other places in the body
 Symptom:
 Reduced bone density
 Increased likelihood of bone breakage
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The Muscular System:
p1006-1011, 123
 Definition:
o A system that moves bones at the joints and pushes substances such as blood, food, and fluids
throughout the body.

List of Main Organs/Structures/Tissues:
o Skeletal Muscle
o Smooth Muscle
o Cardiac Muscle (Heart)

Examples of Two Main Organs/Structures:
o Skeletal Muscle:
 Type of muscle that attaches to bones via tendons.
 Rectangular and striped cells with many nuclei.
 Mostly voluntary; under one’s control.
 Can be made of fast-twitch or slow-twitch muscle fibers
o Smooth Muscle:
 Spindle shaped cells without stripes.
 Involuntary , contract automatically
 Make up the digestive tube, bladder, uterus, and blood vessels.

Smallest Functional Unit:
o Sarcomere:
 A section of a muscle fiber that contains protein filaments that can contract.
 The protein filaments, actin and myosin, grab and pull on each other to shorten the
sarcomere.
 When a nerve impulse is received, calcium enters the sarcomere and regulatory proteins
move off of the binding sites on actin allowing myosin to bind.

How the Organ System Maintains Homeostasis:
o Allows us to actively respond to changes in the external environments as well as providing the
propulsion for the circulatory, digestive, and immune systems.

An Example of Departure from Homeostasis:
o Sore Muscles:
 Causes:
 Intense exercise that does not provide enough oxygen to the muscle cells.
 Lactic acid builds up in cells.
 Symptoms:
 The glucose is converted to lactic acid, which causes muscles to “burn” during hard
exercise.
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The Integumentary System:
p1013-1015

Definition:
o The body system that surrounds all other organ systems.

List of Main Organs/Structures/Tissues:
o Skin:
o Epidermis
o Dermis
o Sweat glands

Examples of Two Main Organs/Structures:
o Keratin:
 A tough, waterproof protein that gives your hair and nails the ability to grow away from the
body, but still maintain shape and sturdiness
 Found in both hair and nails
o Epidermis:
 Outermost layer of the skin
 First layer of protection for deeper skin layers

Smallest Functional Unit:
o Skin
 Made up of three layers
 Outermost layer on body

How the Organ System Maintains Homeostasis:
o Fights infection by preventing bacteria and fungi from entering skin
o Helps maintain body temperature by sweating (sweat glands)

An Example of Departure from Homeostasis:
o Skin Cancer:
 Causes:
 Over exposure to UV rays
 Symptom:
 Irregularly shaped moles on skin
 Uncontrolled cell growth
o Keratin
o Hair
o Nails
o Oil glands