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HUMAN BIOLOGY PART 1
Part One
INTEGUMENTARY SYSTEM
DIGESTIVE SYSTEM
MUSCULOSKELETAL SYSTEM
CARDIOVASCULAR SYSTEM
RESPIRATORY SYSTEM
Part Two
URINARY SYSTEM
NERVOUS SYSTEM
ENDOCRINE SYSTEM
REPRODUCTIVE SYSTEM
INTEGUMENT SYSTEM: Does anyone know what integument means? Integrity?
Holding things together? What part of the body do you think this refers to?
1. Organs (Skin, Nails, Hair, Glands)
2. Functions
a. Protection (Abrasions, pathogens, UV light, Dehydration)
b. Thermal regulation (maintaining proper body temp)
1) Insulation = adipose layer
2) Cooling = sweat glands
c. Sensory reception (touch, temp, pain, etc)
d. Vitamin D production
SKIN
1. Epidermis
2. Dermis
3. Hypodermis (fat layer)
SKIN COLOR
Melanin is a substance that is responsible for skin pigmentation (color)
MELANIN: (dark brown pigment made by special cells called melanocytes in the skin).
The more melanin you make, the darker the skin.
PROBLEMS WITH SKIN
BURNS: Three types:
FIRST DEGREE: Minor burn to the epidermis; sunburn
SECOND DEGREE: Dermis separates from epidermis; blister
THIRD DEGREE: Hypodermis is burned; this is the most dangerous. Severe burns can
get infected and can be deadly because they cause dehydration. 2˚ and 3˚ burns over a
large part of the body gives a survival chance proportional to the amount of skin left.
60% burn = 60% chance of dying. Why are deep burns so dangerous?
1) Infection
2) Dehydration: nothing to keep fluid in body.
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SKIN CANCER: Three major types:
1) BASAL CELL CARCINOMA:
Cancer of the dermis.
Almost never metastasizes or invades the hypodermis.
Looks like shiny nodules
2) SQUAMOUS CELL CARCINOMA
Cancer of the epidermis.
25% of all cancers
Will metastasize if not treated.
3) MELANOMA
When the melanocytes (that produce the pigment melanin seen in freckles and
moles) divide uncontrollably.
Highly metastatic.
DECUBITUS ULCERS
Epidermis is destroyed from prolonged pressure, underlying tissue is exposed.
How decubitus ulcers form:
If you’re sitting down, weight of the body presses against blood vessels, no blood flow to
skin of buttocks. In you, it’s ok, because you’ll be walking around again in a half hour.
But if it there is no circulation for longer than a couple of hours because one can’t move,
tissues can’t get oxygen. Ulcer forms, can get gangrene or go systemic and die of
infection. That’s how Christopher Reeve died.
PSORIASIS: An autoimmune disease of the skin, hereditary; causes flaking skin on
knees, elbows, head; not a cancer. No cure.
CONTUSION: “Bruise”
Why does a bruise look black and blue? The vessels in the hypodermis is ruptured, and
the blood leaks upward; looks blue. As it gets pushed upwards, it appears green/yellow.
The age of the bruise determines the color.
WRINKLES
Over time, collagen fibers align themselves more and more as they are always being
pulled in the same direction: smile, frown.
Skin begins to sag because body makes less collagen. Pinch your grandma’s skin. Does
it bounce back, or ooze back?
What can be done about wrinkles? Not much. Face lift clips off extra skin.
Creams don’t work. Trying to fix a collagen problem with a cream is like trying to
shampoo your carpet by putting the cleaner on the roof!
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BOTOX
This is a deadly poison which paralyses the muscles, making them sag. That releases the
tension, and relaxes the skin line. In 3 months, new muscle cells are made, so wrinkles
come back, and need new injection.
COLLAGEN INJECTION
Collagen is injected into hypodermis. Can last a couple of years.
MOISTURIZER CREAMS
The secret ingredient of all moisturizers is WATER. They work superficially on the
epidermis. The top layer of skin is dead, it just hasn’t flaked off yet. Although it is
waterproof, it swells when wet. So, if you put a moisturizer on skin, the dead cells on top
will expand and hide wrinkles. Get the same effect by soaking in the tub, and that’s
cheaper. If you soak in water a long time, it over-swells, and fingers appear deeply
wrinkled. Moisturizers work best if you soak in the tub so the natural water gets into the
cells, then the cream prevents evaporation. If you wait more than 10 minutes after drying
off, the cream doesn’t have much effect because the water has already evaporated. Once
the water in the skin evaporates, it takes more water with it, so you’ll wind up with dryer
skin if you don’t put moisturizer on it.
TATTOOS
Pigment is injected into the dermis. If the needle is sterile, there’s no health risk.
However, the pigment diffuses with time. What looks good in your 20’s will look like a
blob when you’re 50.Laser treatment is just burning the tattoo off all the way to the
dermis; leaves scar. I used to laser off a lot of gang tattoos in my last year of medical
school at USC. Removing a tattoo will probably leave a scar.
NOSE PIERCING
Let me warn you about nose piercing: There is a region of the face called the “Danger
Triangle” which goes from between your eyes to your upper teeth. All of the blood in
this region drains into the brain, so infection there can cause meningitis and death in 2448 hours. A cut on the forehead isn’t so bad, but a cut on the cheek near the nose is
considered very dangerous and needs immediate antibiotics. A nose piercing can become
a serious infection because some of the worst bacteria in the body is in the nose…that’s
why your mother always told you not to pick your nose. Can you imagine if you put a
hole in your nose and it got infected? A nose piercing that gets infected can cause
meningitis.
WARTS
Warts are caused from a virus that can only get in if there is a break in the skin. It starts
multiplying itself, forming a benign local tumor. Therefore they are found on the hands of
people who get a lot of scratches and the feet of those who go outside without shoes.
That’s it for the organ called skin; now we’ll move on to the organ called NAILS
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NAILS
At the nail root, there is rapid division of skin cells, and as they die, the skin moves up
and creates the nail, similar to hair formation. Taking calcium does not make nails
stronger because there is no calcium in skin cells.
HAIR There are about 2 million hairs on the body; 200,000 on the scalp. Hair is dead
skin cells. HAIR FOLLICLES: If follicle is round, it makes straight hair. If it is oval,
makes wavy hair. If it is oblong, makes curly hair.
Laser treatment or electrolysis to remove unwanted hair is a beam that tries to kill the
root of the hair. But if the hair is not in the cell division phase, it will not die; that’s why
the procedure has to be repeated weekly in an attempt to get the hair while it’s dividing.
Also, if the follicle is curved, the beam might not reach the root, and the treatment will
never be successful on that hair.
Chemotherapy kills cells which are rapidly dividing (cancer cells), so hairs in follicles die
as well as bone marrow cells. That’s why chemotherapy patients are bald.
GLANDS
1.
SEBACEOUS GLANDS produce sebum, which is OIL that coats the hair and
epidermis. IT IS NOT A SWEAT GLAND. It keeps the skin from getting dry
and brittle. The problem is that when you wash the oil away, the skin gets dry.
Has anyone heard of moisturizers with the ingredient lanolin? It is made from
sheep sebum. Some of the largest sebaceous glands are associated with the
smallest hairs (face). When they get clogged, the gland swells  PIMPLE. In
puberty, there is an increase in hormones, and an increase in gland production
leading to pimples. A blackhead is sebum which has bound to an oxygen
molecule.
2.
ECCRINE (SWEAT) GLANDS form the sweat when you exercise.
3.
APOCRINE GLANDS coat the pubic hairs. The hairs function as a wick to
draw the secretions to the surface. These glands also produce hormones called
PHEROMONES.
Pheromones function to regulate menstrual cycles of females. If you put
several women in one room for months, their menstrual cycles will all start to
occur at the same time.
Pheromones also function for sexual attraction. There is no conscious odor.
The smell from the axilla is from bacteria that are attracted by the gland.
Expensive perfumes have pheromones. Guess where they get them from?
The anal glands of male cats! They are designed to attract females. They are
used so women will buy expensive perfume.
4. MAMMARY GLANDS secrete milk.
5. CERUMINUS GLANDS are only found in the ear, and they produce wax.
a. They keep the ear canal from drying out
b. They prevent insects from crawling in; they don’t like walking on the wax.
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FUN FACTS ABOUT EPITHELIUM
The 'bone' in a rhinoceros' horn is simply a mass that is not attached to the skull and is
made of a protein found in our hair and fingernails called keratin.
At birth, the dolphin arrives into the world with a moustache. But due to a natural depilatory
process, within a short period of time the moustache falls off by itself.
The stripes on a tiger are not found just on its coat; the skin of this predator is also striped. But
curiously enough, even though the zebra's coat is striped, its skin is not.
THE DIGESTIVE SYSTEM
Also called the gastrointestinal (GI) system
Functions
 INGESTION Taking food in by mouth
 DIGESTION to break food down into simple molecules
 Mechanical: churning of food in the stomach, manipulation of
food with tongue, tearing and grinding with teeth.
 Chemical: breakdown of food with hydrochloric acid
 ABSORPTION nutrients enter capillaries
 DEFECATION to eliminate solid waste products
Mouth
 Oral Cavity
 Hard and Soft Palate
 Tongue
 Lingual Frenulum
 Salivary Glands
 Parotid, Submandibular, Sublingual
 Teeth
Teeth
When bacteria eat away at the enamel, what’s it called? CAVITY
Bacteria between the gums and the teeth can inflame the gums. This is called GINGIVITIS.
This is the major cause of tooth loss. The tooth loosens and falls out. That’s why you need
to floss.
FUN FACTS ABOUT THE MOUTH
 The enamel in your teeth is the hardest substance in your body.
 Your teeth start growing 6 months before you are born.
 If you are right handed, you will tend to chew your food on the right side of your
mouth. If you are left handed, you will tend to chew your food on the left side of
your mouth.
Termites chew up dirt and dung and make massive homes. If they were the size of a
human, they could make a home taller than the Empire State Building. They also put in
air conditioning systems, covered walkways, stairs and gardens.
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Every person has a unique tongue print.
A giraffe’s tongue is 22 inches long
What animal bite causes the most human deaths? Snakes take their toll, but Mosquitoes
cause millions of deaths a year. The Komodo dragon has saliva so toxic with bacteria, it
just bites it's prey and waits for it to die of infection a few days later.
The average human produces enough spit to fill two swimming pools
GI Tract
 This is a tube through the body, forming the esophagus, stomach, small and large
intestine. The GI tract functions to digest food and absorb the nutrients.
 Esophagus
 Stomach
 Small Intestine
 Large Intestine
STOMACH
Functions:
1. Store Food, so it can be slowly released into a small intestine. Your whole
Thanksgiving dinner can take your stomach diameter from 2” to 8” diameter.
2. Churn food. Secretions from the stomach turns everything gooey, called CHYME.
3. Kill bacteria. The stomach is very acidic (pH 1) like battery acid. Chyme will even
eat through clothing.
4. Some digestion: of proteins.
5. Some absorption: of water, alcohol (alcohol is absorbed in the mouth, too!)
Food takes four hours to completely leave the stomach.
STOMACH ACID
There are gastric pits in the stomach lining. “Gastric” refers to the stomach.
Cells in the gastric pits make acid and digestive enzymes.
There are also lots of goblet cells which make mucus to prevent the stomach from
digesting itself. Bacterial infection can erode this area = GASTRIC ULCER.
 HEARTBURN is when acid goes from the stomach up into the esophagus (ACID
REFLUX). People can take a mild antacid like Tums for relief.
Stomach Cells
 CHIEF CELLS secrete an enzyme called pepsinogen. When pepsinogen is
exposed to hydrochloric acid (HCl), it is cleaved into pepsin, its active form.
Pepsin digests proteins.
 PARIETAL CELLS in the stomach secrete hydrochloric acid.
 They also secrete intrinsic factor, which is needed to absorb vitamin B12, which
is needed to make red blood cells.
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Intrinsic Factor
 A person who lacks intrinsic factor (such as those who have a stomach stapling
procedure or gastric bypass) will not be able to absorb vitamin B12 and they will
get a type of anemia called pernicious anemia.
 Treatment is injectable B12 shots monthly for the rest of their lives. They also
have a new dissolvable sublingual form of vitamin B12
Two major causes of Peptic (stomach and duodenum) Ulcers:
 1) 60% of gastric and up to 90% of duodenal ulcers are due to a bacterium called
Helicobacter pylori.
 The body responds by increasing hydrochloric acid (HCl) secretion, which
erodes the stomach lining. 50% of the world’s population has this bacterial
infection, especially in underdeveloped countries.
 2) NSAIDs (non-steroidal anti-inflammatory drugs, such as aspirin) block
prostaglandin synthesis.
 Prostaglandins promote the inflammatory reaction. They also are found in
the stomach, protecting it from erosion.
 The lifetime risk for developing a peptic ulcer is approximately 10%.
 In Western countries the prevalence of Helicobacter pylori infections roughly
matches age (i.e., 20% at age 20, 30% at age 30, 80% at age 80 etc.).
 Prevalence is higher in third world countries.
 Transmission is by food, contaminated groundwater, and through human saliva
(such as from kissing or sharing toothbrushes or food utensils)
Problems With the Stomach
 The cardiac sphincter doesn’t close well, since it is not a true sphincter;
consequences:
 You can throw up (reverse peristalsis). Rats do have a true cardiac
sphincter, and can’t vomit!
 That’s why rat poison won’t kill people or dogs; they can throw it up.
 Another consequence: hiatal hernia.
FUN FACTS ABOUT THE STOMACH
Astronauts can't belch - there is no gravity to separate liquid from gas in their stomachs.
The Tasmanian Devil can swallow 40 percent of its body weight in a half-hour. That's
like eating 216 hamburgers for lunch!
If you ate like a vulture, you could ear 108 hamburgers in one meal. They eat 20% of
their body weight. Their stomach acid is so strong they can dissolve botulism and
cholera.
Frogs can't vomit, and whenever they need to, they end up vomiting their entire stomach.
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SMALL INTESTINE (Small bowels)
 These are the longest part of the GI tract (9 feet long, 1” diameter)
 The small intestine is the most important region of the GI tract because almost all
of the digestion and absorption of food takes place here.
 The DUODENUM is the first part of the small intestine. There are two ducts at
the beginning of the duodenum from the pancreas and gallbladder.
 The main purpose of the small intestine is to absorb nutrients from the food into
the bloodstream to be taken to all the cells of the body. After the food passes
through the small intestine, it goes to the large intestine.
Problems with Small Intestine
 Inguinal Hernias
 Crohn’s Disease
 Gluten Intolerance
Inguinal Hernia
 The inguinal canal is open in the male to allow for passage of the spermatic cord.
In the female, the area is closed, but weak.
 When there is abdominal pressure (lifting a weight), a piece of small intestine can
push out of this canal, causing pain.
Crohn’s Disease
 Autoimmune disease of the GI tract
 Most common area affected is small intestine
 Inflammation causes pain and diarrhea (may be bloody)
 Genetic cause (high risk if siblings have it)
 Usually occurs in males in their 20’s
 No cure; just treatment of symptoms
Gluten Intolerance
 Genetic autoimmune disorder of the small intestine, causing chronic diarrhea. The
person is allergic to gluten (wheat products). Causes destruction of small
intestinal lining.
 It is characterized by having pale, loose and greasy stools (steatorrhoea) which are
voluminous and malodorous.
 It often presents with abdominal pain and cramping, abdominal distension, and
sometimes mouth ulcers.
 Without adjusting the diet, coeliac disease leads to an increased risk of intestinal
cancer.
ORGANS ASSOCIATED WITH THE SMALL INTESTINE
 Liver
 Pancreas
 Gall Bladder
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LIVER (“Hepatic” refers to the liver)
This is the largest internal organ of the body, located on the right side, below the
diaphragm, and extends below the rib margin. The function of the liver is more complex
than any other organ except the brain.
 Detoxifies chemicals in blood (That’s why CSI autopsies look at the liver for
poisons)
 Stores iron
 Makes blood plasma proteins (clotting factors)
 Breaks down fats and regulates cholesterol
 Breaks down amino acids, producing urea
 Stores excess glucose in the form of glycogen. The glycogen can be broken back
down to glucose between meals to keep the blood glucose levels consistent
throughout the day. MAGIC TRICK!
PROBLEMS WITH THE LIVER
Infection of the liver = HEPATITIS (can be deadly)
CIRRHOSIS is when the liver cells die and are replaced by connective tissue. This is
often from alcoholism, which kills the liver cells.
With any liver disorder bile cannot be broken down. Bile is yellow-green, so it builds up
and can been seen as a yellowish color in the skin = JAUNDICE. Jaundice is not a
disease; it is a symptom of liver disorder. It first shows up as a yellow color in the whites
of the eyes. Newborns get jaundice from a lot of red blood cells being broken down, and
the liver gets overloaded, but it’s harmless. The treatment is UV light or sunlight, goes
away in a few days.
 PANCREAS
 This is a gland that makes hormones, digestive enzymes, and INSULIN, which is a
protein that grabs a sugar molecule in the bloodstream and carries it into each cell.
 If the pancreas is malfunctioning and does not make insulin, the person has
DIABETES.
 The pancreas also produces BICARBONATE to reduce the acidity of the stomach
contents so you don’t get an ulcer.
GALL BLADDER function is to store and concentrate bile.
 Bile emulsifies fat: It breaks down the fat into microscopic droplets which can
then be broken down by pancreatic enzymes.
 When you go to McDonalds and order the Big Mac, fries, and shake, you get 200
grams of fat (one week supply), which globs together in the intestine, and that
much more bile is needed to break it down.
 If there are no fats to digest, the bile stays in the gall bladder until it’s needed. If it
crystalizes  gallstones.
PROBLEMS WITH THE GALL BLADDER
GALL STONES are bile salts that crystallize causing the bile to back up.
The stones block the duct where it enters the small intestine. Treatment is to remove the
gall bladder. Now that person can only eat small amounts of fats at a time.
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LARGE INTESTINE (Colon, or large bowel)
This is 5 feet long and 4” diameter
The large intestine is important for several reasons:
1. Absorbs the water from the food
2. Absorbs electrolytes (Na, K, etc) out of the food
3. Stores feces for defecation
4. Contains bacteria (E. coli), about 3 pounds of it! These bacteria have functions:
a. Make vitamins (B12, K)
b. Allow material to move through large intestine easier
c. Keep out harmful bacteria
d. They eat things you can’t digest
i. Fiber
ii. Some sugars that we don’t have enzymes for
When these bacteria are happy and dividing, they produce gas. If you are lactose
intolerant, you are missing the enzyme to break down lactose so the bacteria gets
more sugar and you get more gas! Beans also have these sugars, so they give you
gas. Mexico has different strains of E. coli in their water; the two strains battle it
out and you get diarrhea. Diarrhea is when the large intestine does not absorb
water  dehydration. Cholera is a disease which attacks the large intestine,
preventing water absorption, and can be fatal in 24-48 hours. The difference
between diarrhea and constipation is the amount of water absorbed.
Intestinal bacteria make vitamins, allow material to move through large intestine easier,
keep out harmful bacteria, and eat indigestibles such as fiber. They do not cause intestinal
cancer.
The large intestine absorbs water, electrolytes, stores feces, and contains bacteria, but it
does not do much digestion.
APPENDIX
Right where the small intestine enters into the large intestine is this little sack filled with
E. coli. It might become inflamed, which closes off the opening. It can rupture =
APPENDICITIS, which needs antibiotics and surgery or can be fatal. Most common
age for this is late teens to early 20’s because a child has a larger opening which shrinks
with age. When you’re done growing, it’s done shrinking, so if you haven’t had a
problem by then, you might be ok.
Up from the cecum is the ASCENDING COLON, TRANSVERSE COLON, and
DESCENDING COLON. Then there is an “S” shaped section called the SIGMOID
COLON, which leads to the RECTUM, and out the ANUS.
PROBLEMS
COLON CANCER is the #1 most deadly cancer (kills more people) because it
metastasizes and there are no symptoms. It can be diagnosed by seeing blood in the
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stool; this is an easy test, but no very accurate because many things can cause blood in
the stool.
COLONOSCOPY is a more accurate test for colon cancer. A tube with a light and a
camera is inserted into the colon, and they look for growths on the walls of the intestine =
POLYPS, which are pre-cancerous growths.
DIARRHEA is too much water in the stool (not enough water absorbed from intestine),
usually caused from food poisoning or other infection, stress, or laxative abuse. Chronic
diarrhea causes dehydration and irregularities in heart beat.
CONSTIPATION is when there is not enough water in the stool (too much water
absorbed by the intestine). Prevention includes drinking more water and fiber. Avoid
laxatives because of their side effects (loss of electrolytes, which can cause problems
with the heart beat). Chronic constipation can lead to hemorrhoids.
HEMORRHOIDS are varicose veins along the rectum. There are large veins along
the rectum, which have become enlarged, painful, and inflamed. They are common in
pregnant women, senior citizens, those who have anal intercourse, and in fighter pilots
from the g-forces they pull. People use Preparation “H” for the symptoms, but it makes
you wonder what happened to Preparations A-G? Hemorrhoids can be surgically
removed if needed.
HOW LONG DOES IT TAKE TO DIGEST A MEAL? Should be about one day.
Because plant cells are made of cellulose and we cannot digest that, you can swallow a
few kernels of corn (whole, without chewing), and you’ll be able to easily see them in
your stools and find out how long it takes to go all the way through your digestive tract.
FUN FACTS ABOUT THE RECTUM
A healthy individual releases 3.5 oz. of gas in a single flatulent emission, or about 17 oz.
in a day.
The bombardier beetle combines chemicals in his rear end and can squirt out boiling hot
acidic liquid which quickly neutralizes any attack.
All land spiders breathe through a hole on the rear part of their bodies.
The Fitzroy river turtle absorbs two-thirds of the oxygen it needs through its rectum.
SKELETAL SYSTEM
FUNCTIONS
 Structural support to the body
 Protection of various regions of the body
 Mineral storage, especially calcium
 Formation of blood cells in the marrow
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Bone Strength and Flexibility
 Bone is made of organic (soft) components and mineral (hard) components.
 The organic components are mainly collagen fibers. This is what gives bone some
flexibility to absorb mild forces without breaking. If you heat a bone on a barbeque grill,
the bone will break when you bend it because the collagen will be destroyed.
 The mineral components give the bone strength. If you soak a bone in vinegar (an acid)
for a few days, you can bend it because the minerals dissolve away, leaving only the
collagen.
TWO TYPES OF BONE TISSUE
 Compact bone (cortical) – dense outer layer of bone
 Found in the diaphysis (shaft) of long bones
 Spongy (cancellous) bone – internal network of bone
 Found in the epiphysis (ends) of bones
BONE SPURS: abnormal growth in response to pressure. Can occur on any bone (e.g. heel).
OSTEOPOROSIS: bones are weakened due to a decrease in the bone mass. Men get it
as well as women. What’s the best way to prevent osteoporosis? Exercise! What does
exercise do? Makes bones bigger.
BONE FRACTURES: The naming of fractures tells you what kind of break occurred.
COMPLETE: bone is broken clear through
INCOMPLETE bone is not separated into two parts.
SIMPLE: does not pierce the skin
COMPOUND if it pierces the skin. Increased chance of infections, maybe life-threatening.
STRESS: least serious, get tiny, almost invisible breaks. Usually from overexertion.
Muscle builds up faster than bone. Six weeks into military basic training camp, see lots
of stress fractures.
VERTEBRAE
These form the “back bone” which protects the spinal cord. They form normal curvatures
in the spine, and are separated by intervertebral discs.
ABNORMALITIES OF THE SPINE
SCOLIOSIS is a lateral curve in the spine
KYPHOSIS is a hunchback curve
LORDOSIS is a swayback in the lower region.
ANKYLOSIS is severe arthritis in the spine and the vertebrae fuse.
INTERVERTEBRAL DISCS
These are made of connective tissue (cartilage) that is solid, yet flexible. Function is for
shock absorption, and a little movement. HERNIATED intervertebral disc happens
when stress is put on it the wrong way. When you bend over, the disc compresses
anteriorly. If there’s a weakness there, it herniates (pokes out). A herniated disc can
press on the spinal nerves and cause a lot of pain or some paralysis. Improper lifting and
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pushing with the back can cause this. One treatment is to put a metal rod in to maintain
the distance between the discs.
KNEE JOINTS
Around this is a JOINT CAPSULE of fibrous connective tissue, which gives it strength.
The joint capsule alone is not strong enough, so they are reinforced by ligaments.
LIGAMENTS connect bone to bone. TENDONS connect muscle to bone.
Inside the knee joint are two tough pieces of cartilage called MENISCI. If you keep your
weight on one foot and then pivot your body, it can tear this knee cartilage. Common
problem in athletes. Never heals, needs surgery to remove the torn piece; ends a sports
career. If really bad, bone will scrape against bone, causing severe arthritis in the joint; will
need total knee replacement eventually.
SPRAINS: when a ligament is torn from its attachments. They can be fairly serious. When
a tendon or ligament is sprained, it can take 6 months to heal, and may even need surgery.
Even a partial tear, you have to be careful.
STRAINS: are injuries where the muscle is overstretched and tears. They are not as bad
since there is a lot of blood supply to muscle, so they heal faster. You can walk on it and it
heals in a couple of days, it’s a strain.
CRACKLING SOUNDS in joints are from the release of gas bubbles in the joint. It does
not lead to arthritis.
ARTHRITIS: (“itis” means inflammation). Types:
1. OSTEOARTHRITIS: common in older people. Known as “wear and tear
arthritis”. The articular cartilage begins to break down, and bone spurs start to grow.
The surface is no longer smooth, and movement now causes pain. Can be mild to
severe, needing joint replacement. These people can actually predict the weather,
since the fluid in the joint is under pressure. As air pressure changes, fluid expands
and hurts more.
2. RHEUMATOID ARTHRITIS: not a disease of old age. It’s an autoimmune
disease where body attacks and destroys the cartilage in synovial joints. They swell
and become unusable, causing knarled hands and feet. Usually need joint
replacements.
3. GOUTY ARTHRITIS (gout). Caused by eating too much red meat or protein.
These foods break down into urea, an acid, which causes uric acid crystals in the
joints. They form in the cooler areas of the body, especially big toes. Was more
common years ago when people ate nothing but meat. The crystals cause the joint to
swell up.
FUN FACTS ABOUT BONES
Babies are born with 300 bones, but by adulthood we have only 206 in our bodies.
About 50% of Orangutans have fractured or broken bones, a consequence of regularly
falling off trees.
The giraffe has the same number of bones in its neck as a human: seven in total.
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The elephant's trunk is so sensitive that if it were disposed to, it could lift a sewing
needle. But the infants of this species can take up to six months to learn how to control
and manage their own trunks.
The woodpecker has head movements at 20 per second, and have a spongy area behind
their beaks that works as a shock absorber.
The long horned ram can take a head butt at 25 mph. The human skull will fracture at
5mph.
The beaver can cut a trunk that is 25 cm in diameter in six seconds. If the beaver didn't
dedicate itself to filing its teeth, these would grow to the point of piercing its lower jaw.
MUSCULAR SYSTEM
TENDONS are structures that attach a muscle to bone.
LIGAMENTS are structures that connect one bone to another bone.
Exercise  Muscles HYPERTROPHY (growth in size)
Lack of use  Muscles ATROPHY. This happens quickly. Astronauts can lose 40% of
their muscle in two weeks! It is regained quickly, too.
After exercise, you can get sore…why? Muscle is torn.
Strength training should be done every day. No Pain – No Gain is a fallacy. You can
gain strength and size without pain. Eating protein also does not increase muscle. The
average person only needs one ounce of protein a day, two if you work out. Two ounces
is like one mini hamburger. Most people eat too much meat.
MUSCLE DISEASE: MUSCULAR DYSTROPHY
This is a genetic lack of a protein so the cell won’t contract = paralysis.
FUN FACTS ABOUT STRENGTH
The strongest humans can lift about 3 times their own body weight, but the average
gorilla can lift 10 times it's own body weight! Gorillas can lift 4,600 pounds. By the way,
they don’t drink water. They get it by eating 50 pounds of plants a day.
The rhino beetle can carry 800 times its own weight.
And, pound for pound, the African Crowned Eagle can carry more than a cargo plane,
because it can fly carrying up to 4 times it's own weight. Something that would keep a
cargo plane grounded.
But the strongest creature is the ant. If you had the strength of an ant, you could lift over
your head and carry 6,600 pounds.
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HUMAN BIOLOGY PART 1
FUN FACTS ABOUT THE THIGH AND LEG
If we could jump like a locust, we could jump 300 feet. Locusts have massive muscles in
their thighs and it has elastic bands in its knees that are like stretchy springs that store
energy. The tendons in our fingers store enough energy for us to snap our fingers.
At 60 mph, the cheetah is fast, but the basilisk lizard runs so fast that it can walk on water
and the ostrich is just about the fastest animal on two legs.
What’s the fastest animal on Earth? The tiger beetle, which can run up to 171 times its
size in one second. Despite its famous reputation, the cheetah would have to run 770
kilometres per hour just to catch up with it.
What’s the slowest animal in the world? The sloth. It is a species that moves just five
times faster than a snail!
The penguin burns twice as much energy as any other animal when walking. This is due
to the fact that its legs are very short, and so it must expend a lot of effort in order to get
moving.
Elephants can't jump, not even with the help of hurricane-force winds. It is too heavy to
lift all four legs at the same time.
The flea, however, can jump up to 200 times its own height. This is equivalent to a man
jumping the Empire State Building in New York.
CIRCULATORY SYSTEM
COMPONENTS OF CIRCULATORY SYSTEM
1. Blood
2. Heart
3. Blood vessels (arteries, capillaries, veins)
4. Lymph and lymph vessels
Blood consists of the following:
A. Plasma
B. Red blood cells
C. White blood cells
D. Platelets
A. PLASMA
Plasma is what the blood cells float around in. If you spin a blood sample in a test
tube, the red blood cells sink to the bottom, and you’ll see the yellow plasma on top.
Some people who need blood just need the packed RBCs, others need the plasma, and
some need whole blood, which is both plasma and RBCs. The plasma also carries
around the platelets and some white blood cells.
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HUMAN BIOLOGY PART 1
PLASMA CONTENTS
1. Water (90%)
2. Dissolved substances (10%)
a. Proteins
i. Antibodies
ii. Clotting factors
iii. Lipoproteins (move fats through blood: HDL, LDL)
b. Nutrients
i. Glucose (main energy source)
ii. Amino Acids (builds proteins)
c. Wastes (urea)
d. Gases (O2, CO2, Nitrogen)
e. Electrolytes = ions (Na+, K+, Cl-, Ca++)
A. RED BLOOD CELLS (ERYTHROCYTES)
These are among the smallest cells in the body. There are about 5 million of them in
each of us.
a. They have no nucleus
b. Filled with a red pigment called hemoglobin, which carries O2 throughout
the body. Oxygenated Hb is bright red, deoxy Hb is dull red. Blood in the
veins only looks blue because you are seeing the dull red color through a
yellow fat layer in the skin and subdermal tissue.
c. Average life span is 120 days. They are made in the red bone marrow,
and the old ones are destroyed in the spleen and liver, and Hb is recycled.
During your lifetime, about 250 billion of these cells are destroyed, and
250 billion are made.
2. WHITE BLOOD CELLS (LEUKOCYTES)
There are different kinds; all fight infection. They seep out of the blood vessels
whenever they sense bacteria nearby.
a. NEUTROPHILS: The most common type. They are the first to respond
to infection. They engulf and eat (phagocytize) bacteria. They mostly
hang out in the circulating blood and scout around the body for where they
are needed.
b. MACROPHAGES. They are like large neutrophils that also phagocytize
bacteria and foreign objects (like a thorn that breaks off in the skin. They
mostly hang out in our tissues.
c. LYMPHOCYTES
i. B CELLS: Make antibodies (proteins that fight infection)
ii. T CELLS: Kill bacteria and viruses. They also coordinate the
immune response. This is the cell that is attacked by the HIV
(AIDS) virus.
3. THROMBOCYTES (Platelets)
These clot blood. When a platelet encounters a broken blood vessel it releases a
substance that clots blood. Platelets are responsible for clot formation.
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HUMAN BIOLOGY PART 1
HEMOPHILIA is a hereditary disease of males, where they are unable to clot
properly. When they get even a slight bump or bruise they have to have an
intravenous infusion of clotting factors or they will bleed to death. This is
probably the disease that was in the genes of Henry VIII, which caused all of his
male children to become weak and die in infancy.
STEM CELLS: A cell that has not matured and differentiated (become specialized) yet.
An embryo has lots of stem cells which have not decided to become a nerve cell, muscle
cell, liver cell, etc. Stem cells become the type of cell the body needs. The placenta of a
newborn infant has many of these stem cells, too, but not as many as an embryo. That’s
why people want to research stem cells on embryos; there are more stem cells there.
ANEMIA: If the body makes too few erythrocytes, or abnormal ones.
a. Causes of anemia include lack of iron, lack of hemoglobin, hemorrhage,
lack of vitamin B12 (needed to make red blood cells).
b. Characteristic sign of anemia: pale skin and fatigue.
LEUKEMIA: Cancer of the blood is called leukemia. It actually only involves the white
blood cells. Something goes wrong in one stem cell, and it starts making huge amounts of
clones of itself which don’t work right and not enough normal white blood cells are made.
Therefore, the body cannot fight infection. There are many types of leukemias.
BLOOD TYPING: The ABO SYSTEM
Blood typing is the technique for determining which specific protein type is present on
RBCs. Only certain types of blood transfusions are safe because the outer membranes of
the red blood cells carry certain types of proteins that another person’s body will think is
a foreign body and reject it. These proteins are called antigens (something that causes an
allergic reaction). There are two types of blood antigens: Type A and Type B.
A person with Type A antigens on their blood cells have Type A blood.
A person with Type B antigens have Type B blood.
A person with both types has type AB blood.
A person with neither antigen has type O blood.
If a person with type A blood gets a transfusion of type B antigens (from Type B or Type
AB, the donated blood will clump in masses (coagulation), and the person will die.
The same is true for a type B person getting type A or AB blood.
A child will get these antigens from each parent. For instance, a man with type AB blood
will give each of his children either type A, type B, or type AB blood. A man with blood
type AB could NOT be the father of a child with the blood type of O.
Type O blood is called the universal donor, because there are no antigens, so that blood
can be donated to anyone. Type AB blood is considered the universal acceptor, because
they can use any other type of blood. This blood type is fairly rare.
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HUMAN BIOLOGY PART 1
RH FACTOR
There is another term that follows the blood type. The term is “positive” or “negative”.
This refers to the presence of another type of protein, called the Rh factor. A person with
type B blood and has the Rh factor is called A-positive. A person with type B blood and
no Rh factor is called B-negative.
The reason this is so important is that if an Rh- mother has an Rh+ fetus in her womb
(from an Rh+ father), her antibodies will attack the red blood cells of the fetus because
her body detects the Rh protein on the baby’s red blood cells and thinks they are foreign
objects. This is called Hemolytic Disease of the Newborn (HDN).
HEART BEATS
The pressure of blood against blood vessel walls is called blood pressure.
Blood pressure is recorded systole over diastole. 120/80 is normal.
When blood pressure is too high, it is called HYPERTENSION.
The heart normally beats at a rate of 60-80 beats per minute. A faster or slower heart rate
is an indication of a problem.
ARRHYTHMIA = improper heart beat; needs medicines or a pacemaker.
FIBRILLATION is when the heart beat is rapid and uncoordinated, and doesn’t contract
rhythmically and just quivers without pumping blood. It needs an electric shock from a
defibrillator. This machine is never used when someone’s heart is beating, even
irregularly, because it can cause the heart to stop. Whatever caused the fibrillation in the
first place is not treated, so it may not work, but it’s worth a try! Most large public
facilities have them. There are three on this campus. Disneyland has one every 100 yards.
THE HEART NEEDS ITS OWN BLOOD/O2
The blood vessels for the actual muscle that makes up the heart comes from vessels that
are on the outside of the heart = CORONARY ARTERIES.
The more you exercise, the more branches of these arteries are formed, and the better the
blood supply to the heart. Blockage in the coronary arteries is called a heart attack.
For a narrow coronary artery, you can do a CORONARY BYPASS. Take another blood
vessel graft (from thigh) and go around the blockage. For double or triple bypasses,
that’s how many vessels are affected.
HEART ATTACK
Not enough blood to the heart (lack of oxygen) severe pain  ANGINA.
If there is complete blockage  not enough O2 to that area  that part of heart muscle
dies = MYOCARDIAL INFARCTION (HEART ATTACK). Heart muscle never
regenerates. If a large area dies, person will die.
What are symptoms of a heart attack? Chest pain, pain down left arm, shortness of breath,
nausea, tight pressure in chest, feeling of indigestion or heartburn, even pain in the jaw
that is mistaken for a toothache. A common symptom is death. 50% of first heart attacks
are fatal. About ¾ million people die each year from heart attacks.
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HUMAN BIOLOGY PART 1
Reasons for blockage
ATHEROSCLEROSIS = build-up of fat inside artery (called a PLAQUE) 
narrowing of artery  blood clot. If clot is big, it can break off and go to the lungs.
When a clot lodges in an artery, all the tissue beyond that point gets deprived of oxygen
and dies.
FUN FACTS ABOUT THE HEART
According to German researchers, the risk of heart attack is higher on Monday than any
other day of the week.
A Giraffe’s heart is 2 feet across.
Heart disease is a big killer, but what animal causes the most human deaths? Annual
human deaths due to sharks is 10; however, 100 more people die each year from being
stepped on by cows. But the whitetail deer causes the most deaths because of all the
traffic accidents they cause.
All mammals produce almost one billion heartbeats before dying. The mouse produces
close to one billion, but its life cycle is just 850 days. The elephant has about 75 years
through which to spread out those heartbeats. Humans are the exception. They have about
3 billion heartbeats per life.
The blue whale is the largest creature that has ever lived on this planet, weighing about
170 tons which is the combined weight of 22 elephants and the length of seven giraffes
lying in a row. It would take a sloth more than half an hour to go from one end to the
other. Its heart is as large as a small car, and its arteries are so wide that a man could
swim in them without much trouble.
RESPIRATORY SYSTEM
Main Function = gas exchange from O2  CO2
Other functions: speech (sounds) regulation of pH of blood.
1. NOSE: This is made of cartilage. Nose jobs involve taking a mallet, breaking the
nasal bone and shaving the cartilages.
a. NASAL CAVITY: This is where the nostrils are. They have hairs which
filter large particles in the respiratory tract. (insects, etc).
The functions of the nasal cavity is for the air you breathe:
1. Warm (cold air can freeze lungs); warmed by superficial veins
2. Clean (dirty air can clog lungs); mucous is sticky, and cilia will move
that dirt down the back of the throat, then it’s swallowed.
3. Humidify (dry lungs can crack). The fluid secreted by glands makes
the moisture, even on windy days the air goes to 100% humidity by the
time it gets to the lungs.
When you have a cold and get extra fluid (edema)  stuffed up or runny nose,
and the pressure can cause sinus headaches.
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HUMAN BIOLOGY PART 1
2. PHARYNX is where the nasal passages join with the oral passages. The
AUDITORY TUBE from the ears is located here.
A. SOFT PALATE: move your tongue along the roof of your mouth, and
going from the front to the back you’ll feel the hard part turning into a
soft part on the roof of your mouth.
B. UVULA: located at the end of the soft palate (seen in cartoons).
The function of the soft palate and uvula is to move upward when
swallowing, to prevent food from going into nasal cavities. When you
vomit, they don’t close, and food and stomach acids go into nasal cavity and
3. LARYNX
This is a very complex structure. Made up of cartilages
It has two functions:
1. Produce sounds (vocal cords are located in the larynx)
2. Prevent food from entering lungs
A. EPIGLOTTIS closes when you swallow so nothing will go into the trachea and
lungs. When you get hiccoughs, it’s from a sudden movement of air into the lungs, so the
epiglottis closes to prevent more air from going in. It’s unknown why you get hiccoughs.
All the treatments you can try involve interrupting the normal breathing patterns.
B. GLOTTIS is the opening where the air goes to reach the lungs.
C. VOCAL CORDS
Vocal cords are attached to cartilage. If these cartilages move, the vocal cords open.
The type and pitch of sounds you make depend on how far apart the vocal cords are.
Way open = no sound (like when breathing)
Mostly closed = sounds
Men: their thyroid cartilage is larger, so their vocal cords are longer = deeper voice.
LARYNGITIS: inflamed vocal cords (↓ sound production).
Singers can get scar tissue nodules, requires surgery.
4. TRACHEA This is a tube that carries air from the larynx to the lungs.
It’s fairly rigid from about 16 rings of cartilage.
The purpose of the cartilage rings is to keep the trachea open like a hollow tube.
The trachea branches out into smaller tubes called BRONCHI.
Bronchi branch out into smaller tubes called BRONCHIOLES.
Bronchioles branch out into smaller tubes that empty into a sack = ALVEOLI. This sac
is like a balloon surrounded by a capillaries. The alveoli are where the gas exchange
occurs: oxygen goes from the air in the lungs into the red blood cells passing by there,
and carbon dioxide diffuses out of the cells and into the air in the lungs where it is
exhaled. Therefore, inspired air (breathe in) contains oxygen, and expired air (breathe
out) contains more carbon dioxide than oxygen.
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HUMAN BIOLOGY PART 1
DIAPHRAGM is a muscle on the floor of the chest cavity. It is involved in breathing.
FUN FACTS ABOUT THE LARYNX
A cough can be expelled at 60 mph.
The number one sign that a person is lying is voice irregularities.
The blue whale's song can reach 188 decibels - that's as noisy as a rocket.
MYTH: Cover your head or catch a cold: Although 90% of the heat lost from the body is
lost from the head, covering your head will not prevent this heat loss. The heat is lost
from the warm air that you exhale.
PROBLEMS WITH THE LUNGS
In allergic conditions, bronchioles will constrict, blocking air flow to the lungs =
ASTHMA. This can also be caused by irritants in the environment, especially by
pollution in the city.
SMOKING
Smoking destroys cilia, and smoke of any kind is toxic. Particles in the lungs can’t clear.
Cigarettes contain tar, which is the same kind of tar used to pave roads. When there is a
thin lining of tar on the alveoli, there is no oxygen exchange to the lungs there. Large
chunks of the lung become useless. Damage to the lungs shows up several ways.
If a person smokes for 10 years and then stops, the damage will repair. If they have been
smoking longer than 10 years, they may have some residual damage. It takes 7 years for
lungs to repair. Smoking right after exercise is worse because you are breathing more
deeply, so the particles go in deeper. Pollution in the air can also cause particles in the
lungs, and the ozone can damage the lungs. Living in southern California is like smoking
one pack a day.
A mother who smokes during pregnancy will give birth to a baby with a lower birth
weight. Smoking also is associated with heart disease, cancer of the lung, bladder, and
pancreas. It also causes emphysema, pneumonia, and bronchitis. Some people try to quit
smoking by smoking less, trying not to inhale, or switching to chewing tobacco, but there
is no safe way to use tobacco.
CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)
Number 5 killer in the USA.
It is a combination of two conditions:
1. CHRONIC BRONCHITIS: inflammation of the bronchi, produces mucous, the
openings become smaller = obstructed.
2. EMPHYSEMA: loss of elastic tissue on the bronchioles and alveoli, which
collapse now during exhalation. Alveoli lose their shape and their surface area.
When you see someone at the mall with an oxygen tank, they probably have
emphysema, and need pure oxygen.
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HUMAN BIOLOGY PART 1
LUNG CANCER
There are many types of lung cancers. About 150,000 die each year from them.
It is the #1 or #2 most deadly form of cancer. 85% of lung cancer is caused from
smoking.
The problem is that it starts as a hard nodule deep in the spongy tissue of the lung, where
it has no symptoms until it presses against a structure. By then, it has also
METASTASIZED (bits of cancer cells break off and travel to another location in the
body, lodge there, and start multiplying). Surgery on the lung cancer of a smoker won’t
work because the lungs are too weak, and they can’t do without the lung tissue. There
are no good screening procedures for lung cancer.
SURFACTANT is a slippery soap that is made by the alveoli, which coats it and keeps
the walls of the alveoli from sticking together when they collapse during exhalation. If
you have two wet pieces of paper and stick them together, they are hard to pull apart
without ripping. Put soapy water between them, and you can pull them apart.
The reason this is important is because surfactant is not produced in a fetus until the ninth
month, so premature babies don’t have enough surfactant  RESPIRATORY
DISTRESS SYNDROME, which is the #1 cause of death in premature babies. You
know how hard it is to blow up a brand new balloon? Imagine a baby having to do that
with every single breath. You get tired. The treatment is to spray artificial surfactant into
the lungs, and put them on a respirator to push air in. The more distal regions are still
collapsed, so there are still problems.
PNEUMONIA is when there is fluid in the lungs, usually from a viral or bacteria
infection of the bronchi and alveoli. Blood plasma leaks out and fills the lungs, making it
difficult to breathe. Needs hospitalization with iv antibiotics.
TUBERCULOSIS is an infection of a really bad bacteria that get in the lungs and make
themselves a fibrous shell (called a capsule) to hide in, where antibiotics can’t reach.
They set up shop in the lungs and reproduce. Soon, the lungs fill up with these hard nodes
and make it difficult to breathe. It causes extreme coughing, and then lots of these
bacteria break off and get spewed into the air, where someone else can inhale them. It is
extremely contagious and very deadly. If a person gets TB, the State Health Department
has to be notified. They will show up at your house every morning for six months and
stand there and watch you take your pills. If you don’t accept this, they have the right to
haul you away to a lock-up facility and force the medicine in you for six months.
Diseases like TB and the plague have almost wiped out Europe! A TB test will be
positive if you have been exposed to the organism at any point in your life. Then you’ll
have to go in for an x-ray to see if it is an active case of TB or not. Once you recover
from TB you will always have a positive TB test, so tell the nurse that in advance. You
may have to provide documentation that you have been treated for it already. Most
employers require TB tests before hiring. I had to take one to work here.
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