Body Systems Ch. 8-12
 Body
organization: cells,
tissues, organs, organ systems.
 There are 11 major body
systems that work together to
make your body function.
Skeletal System
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Bones, cartilage and connective tissue
Approx. 206 bones
Compact bone-has no visible open spaces; rigid,
dense; outer layer
Spongy bone-has many open spaces; provides strength
and support; the second layer
Marrow-soft tissue; red produces blood cells; yellow
stores fat
Joints-three types-gliding (wrist); ball-and-socket
(shoulder); hinge (knee)
Muscular System
 Smooth
muscle; involuntary; digestive
system
 Cardiac muscle; involuntary; only in your
heart
 Skeletal muscle; voluntary and
involuntary; attached to bones by
tendons; work in pairs; muscles that
straighten-extensor (triceps); that bendflexor (biceps)
Integumentary System
Protects, covers and maintains
homeostasis
 Includes hair, skin, and nails
 Two layers of skin: epidermis and
dermis
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Cardiovascular System
Heart, blood, blood vessels
 Maintains homeostasis (carries nutrients
and removes waste)
 Heart-cardiac tissue; about the size of your
fist. Mammalian hearts have four
chambers-2 atria (top) and 2 ventricles
(bottom); valves between chambers and
the major arteries
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Continued
Blood vessels-arteries, veins, capillaries
 Arteries carry blood away from the heart;
have a layer of smooth muscle which also
pump with the heart
 Capillaries allow exchange of
 nutrients and wastes between the blood and
cells
 Veins carry the blood to the heart; valves in
them prevent backward bloodflow.
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Lymphatic System
Fights pathogens (germs) and collects excess fluids
 Carries fluids in lymphatic vessels throughout your
body
 Lymph nodes-thoughout the body, filter lymph
(fluid) and remove dead cells and pathogens from
the body; this is why they swell when you have an
infection!
 Thymus, tonsils and spleen are other parts of the
system.
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Digestive System
Breaks down food
 Food passes through mouth, esophagus,
stomach, small intestine, large intestine,
rectum
 Part of system but food doesn’t go
through:teeth, gallbladder, liver, pancreas
 Teeth and saliva begin breaking down food
mechanically and chemically.
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Esophagus pushes food down by
peristalsis (sm. Muscle movement)
 Stomach churns and uses acid and
enzymes to break down food.
 Small intestine is covered with villi,
which absorb the nutrients into the
blood.
 Liver produces bile which is stored in
the gallbladder, which is secreted into
the sm. Int. to break down fats.
 Large intestine absorbs leftover water
back into the body.
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Urinary System
Removes
waste products
from the blood.
Kidneys filter the blood to
remove wastes and water.
Nervous System
 Divided
into two: Central Nervous
System (brain, spinal cord) and
Peripheral Nervous System (all
other parts)
 Gathers and interprets information
from the environment and your
body. Sends signals to your body.
Endocrine System
Controls the body’s functions through
hormones (chemicals).
 Hormones include epinephrine
(adrenaline), thyroid hormone,
estrogen, testosterone, insulin.
 Glands secrete hormones: pituitary,
thyroid, adrenals, pancreas, ovaries and
testes.
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Reproduction
 Sexual
reproduction involves the
union of two gametes (egg and
sperm).
 External fertilization takes place
outside the female’s body. Frogs,
many fish, use ext. fertilization.
 Internal fertilization takes place
inside the female’s body.
Mammals
Mammals produce milk for their young.
There are three types:
 Monotremes: lay eggs; platypus
 Marsupial: give birth to partially
developed young that continue to
develop in a pouch. Opossum, koala
 Placentals: give birth to a more
developed newborn than marsupials;
nourished inside the mother’s body.
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Placentals/Humans
Words to know:
Umbilical Cord-connects the fetus (baby)
to the placenta; contains large blood
vessels
Placenta-structure that forms on the wall
of the uterus that allows for the
exchange of nutrients between fetus
and mother
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In males, sperm are produced by the
testes, which also produce testosterone.
 In females, eggs are produced by the
ovaries and released usually once every
21-40 days during the menstrual cycle.
 Menstrual Cycle-starts at puberty and
continues through the 40s or 50s;
prepares the body for pregnancy; an
egg matures, is released, then if not
fertilized, is shed with the uterine lining
in a process called menstruation. This
bleeding lasts about 5 days (3-8). The
cycle then starts over.
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Development
IF the egg is fertilized, the egg is now
called a zygote. Once it divides, it’s
called an embryo.
 The embryo will move down the
fallopian tube into the uterus (fig. 1 p.
318) where it may implant into the
uterine lining.
 Timeline-p. 321
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