Human Body System Review
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Muscular System:
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Helps the body move, helps with posture, helps body fluids move and helps maintain body
temperature
Skeletal muscles- muscle attached to the skeleton, these move when actin and myosin filaments
merge. ATP supplies energy for muscle fiber contraction.
Smooth muscle-lack striations occur in separate fibers, found in blood vessels, stomach,
intestine, bladder and uterus.
Cardiac muscle-heart muscle
Common skeletal muscles are: trapezius-back of shoulder; deltoid-shoulder; bicep-upper arm;
tricep-lower arm; abdomen & obliques-stomach; soleus-calf; front of upper leg-quadricep;
back of upper leg- hamstring
Ligament- connective tissue joining bone to bone
Tendon-connective tissue joining muscle to bone
Flexor- bends at joint(bicep); extendors- unbend at the joints (tricep); abductor- take away from
the body; adductor-moves toward body
Nervous System:
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Provides rapid and precise control of muscle and glands as well as controls and coordinates
body activities.
Brain and spine are central nervous system (CNS)
Branches of CNS are peripheral nervous system (PNS)
Autonomic nervous system are automatic actions controlled by the hypothalamus, brain stem
and spinal cord.
Spine: central gray matter surrounded by white matter that provides a two-way communication
between the brain and body.
Brain: composed of cerebrum, cerebellum and brain stem; cerebrum is marked with ridges and
grooves and part of higher brain function, memory, thought and reflexes.
Brain stem controls sensory impulse, cerebellum controls coordination and movement
Synapse is a junction between neurons; nerves: cord-like bundle of nerve fibers; neurons are
multipolar, bipolar and unipolar
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Nerve cell is made up of a cell body-with nucleus, axon-send impulses from cell body to neuron
dendrite or other body cells, dendrite- electrical messages received at synapse and synapselocation of transmitted messages.
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Example of nerve cell
Somatic System or Five Senses
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Touch- you have pressure, thermo and pain receptors.
Smell-Olfactory organs are in your nose, olfactory receptors are neurons with cilia that are
sensitive to fat-soluble chemicals. The smell receptors are high up behind the nose and are
sensitive to chemicals in mucus. Primary odors are camphor, musky, floral, peppermint,
ethereal, pungent and putrid.
Taste-taste occurs because of taste buds with receptor and supporting cells. These determine
flavor and palatability. The palate is at the top of the mouth between sinus and tongue. Teeth
help tear, chew and grind food. Taste is affected by smell and primary taste buds are sweet,
sour salty and bitter and now umami.
Hearing- ears collect sound waves, the middle ear conducts sound waves. Eustachian tubes
connect the middle ear to the throat and maintain air pressure. The inner ear includes the
cochlea and corti which receive vibration of fluids. Hair-like receptors send impulses to auditory
nerves, then to the brain where sound is interpreted. The bones in the inner ear are the anvil,
stirrup and hammer and the fluid in the inner ear determines balance.
Sight- The outer part of the ear is the cornea which lets light enter. Middle of the eye is the
choroid which is vascular and contains pigment. This includes the iris, pupil and lens. The inner
eye holds the retina that contains the visual receptor cells. Light waves are refracted by the
cornea and lens to focus an image(upside down) on the retina. Rod and cone cells help us to see
color and sharp details. Optic nerves send messages to the brain and the brain turns the image
right side up and image is interpreted by the occipital lobe. With 2 eyes you see 3D, this also
increases the angle of vision and depth perception.
Digestive System
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Functions include receiving food, modifying food, absorbing nutrients and eliminating waste.
Mouth- food enters here, then teeth chew food and tongue moves food.
Esophagus- food is moved from the move down this smooth muscle into stomach.
Stomach- food is dropped from the esophagus where food is churned and broken down by
hydrochloric acid.
Liver- food does not go to the liver directly, but through the bloodstream via the small
intestines, toxins are filtered here. Nutrients are also stored here for cell rebuilding and energy.
The liver also converts ammonia to urea.
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Pancreas- produces enzymes to help with absorption of food. Insulin is regulated in the area.
Gall bladder- produces bile to help with digestion.
Small intestine- food is broken down further so nutrients can be absorbed into the bloodstream
through the many villi in the long small intestine. Parts include duodenum where food is broken
down by pancreatic enzymes, jejunum where villi start absorption and ilium where villi obtain
the last of the nutrients.
Large Intestine- Water is absorbed here and vitamin k is produced. This is also called the colon.
Rectum- the holding area for waste.
Anus- where waste exits the body.
Respiratory System
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Main function is to obtain oxygen(O2) for the body and rid the body of carbon dioxide (CO2)
Sinus- the spaces in the bones that open into nasal cavities lined with mucus.
Nasal Cavity- the space behind the nose that traps particles, warms and moistens air.
Mouth- another opening for inhaling air.
Pharynx-common passage for air and food, aids in creating vocals.
Larynx- located at the top of the trachea, contains vocal chords.
Epiglottis- in the air passageway, this prevents objects from entering the trachea.
Trachea- leads to branched air passages.
The trachea branches further and further in the bronchi, bronchus, and bronchioles referred to
as the bronchial tree. These parts distribute air to all parts of the lungs. They are located in the
lungs.
Lungs- This includes part of the bronchial tree and alveoli( tiny air sacs where oxygen and carbon
dioxide are exchanged), blood vessels and supporting tissue. Oxygen enters artery by diffusion.
Oxygen goes into arteries, carbon dioxide into veins for exhalation.
Diaphragm- muscle under lungs that contracts and relaxes because of elasticity in muscle.
In the medulla oblongata near the midbrain, control of breathing is located in the pons.
Circulatory or Cardiovascular System
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A closed system that transports blood, exchanges gas, nutrients and wastes between blood and
body cells.
Heart- pumps blood to parts of the body and lungs.
Veins- carry blood containing more carbon dioxide from body to heart then lungs.
Arteries- carry blood containing more oxygen to the body from the heart.
Venules- small blood vessels that merge with the veins and return blood from other tissues to
the heart.
Arterioles- Small blood vessels that carry arterial (oxygenated) blood.
Capillaries- the smallest of the blood vessel where gas exchange takes place and nutrients and
waste are also exchanged between blood and body cells.
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Path of the blood through the heart: Fresh oxygenated blood from the lungs goes to the left
atrium, then left ventricle to the aorta to the body, back from the body to the superior vena
cava to the right atrium then to the right ventricle and back to the lungs to rid the body of
carbon dioxide and gain fresh oxygen for the lungs and body again. Atrium are the top chambers
of the heart, ventricles are the lower chambers of the heart.
Blood pressure is the force of the blood pushing against the walls of the arteries.
Systolic blood pressure (the top number) measures the amount of pressure that blood exerts on
vessels while the heart is beating. Diastolic blood pressure (the bottom number) measures the
pressure in your vessels between heartbeats.
Excretory System
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This system removes water, salts and nitrogenous wastes and ammonia from the body.
Two kidneys- filters blood through nephrons specifically the Bowman ’s capsule, urine is the end
product. Kidneys also produce renin that regulates blood pressure
Ureter- the tube from the kidneys to the bladder.
Bladder- holds urine that has had urea removed by the kidneys
Urethra- conveys urine from bladder to the outside of the body.
Integumentary System or Skin
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The function is to protect the body, regulate body temperature and blood pressure, house
sensory receptors and synthesize chemicals.
Epidermis- Outer layer of the skin, protects tissue, prevents water loss, location of pigment, hair
shaft and nails.
Dermis- contains hair follicles, sebaceous glands, sweat glands, nerves and blood vessels. The
location is under epidermis.
Hypodermis or subcutaneous layer- underlying fat tissue. This attaches to bone or muscle.
Vitamin D is synthesized from skin exposed to UV light and is needed for bone and tooth health.
The skin excretes excess water and minerals through sweat. This cools the body.
This is the largest organ in the body.
Melanin is responsible for pigment or color in our skin.
Hair and nails are made up of dead keratinized epithelial (Skin) cells.
Endocrine System
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This is made up of cells, tissues and organs that secrete hormones into body fluids that regulate
body function and activity.
The brain contains the hypothalamus that controls pituitary( body growth) secretions and is the
mediator between the nervous and endocrine system; pituitary gland (the master gland)that
stimulates cell growth and other sex cell development, and the pineal gland which secretes
melatonin that regulates sleep.
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Near the throat is the parathyroid gland which increases blood calcium and absorption of
calcium and the thyroid gland that controls metabolism and growth of nervous system.
On the kidneys are the adrenal glands which secrete (nor)epinephrine which stimulates
reaction, and regulates salts in body fluids. This is the “fight or flight” gland.
The pancreas regulates glucose, fat, storage and protein synthesis.
The thymus gland helps in the development of the immune system.
Skeletal System
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Provide support and protection for soft tissue, helps with movement, makes blood cells and
stores salts.
The skull(cranium) protects the brain.
The spine or vertebral column protects the spinal cord.
The top 7 ribs connect at the sternum (over heart) and are true ribs. The next four are indirectly
attached to the sternum and are false ribs. The last two ribs are floating ribs.
The radius is the thumb side of the lower arm and the ulna is longer than the radius in the lower
arm while the humerus runs from the scapula to the elbow.
The scapula is the shoulder, and clavicle is the collar bone.
The hand is the metacarpals and feet the metatarsals. The wrist is named carpals and fingers
and toes are phalanges.
The femur is the largest bone and runs from the knee to the hip; the tibia is the shin in the lower
leg and the fibula is the smaller lateral bone in the lower leg. The knee cap is the patella
Blood cell formation occurs in the bone marrow. The red marrow produces red blood cells,
lymphocytes and platelets; Yellow marrow stores fat and may become red if needed.
Bones store calcium and provide lever action to lift and move.
Inside the bone are the periosteum which houses osteoblasts(bone formation cells)
Compact bone is very hard, porous and hollow, this allows the passage of blood vessels and
nerves.
Spongy bone produces red and yellow bone marrow.
Types of bone: Long bones- examples: femur, humerus, ulna, radius, tibia, fibula, metacarpals
Short bones- examples: bones of the wrist
Flat bones- examples: sternum
Irregular bones- those who are not classified in the third categories