ANATOMY LECTUREComprehensive Review1

TISSUES AND ORGANS

TISSUE: A group of cells, usually similar, which share a particular function.

Each ORGAN is made up of one or more tissues.

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INTEGUMENT SYSTEM ARRECTOR PILLI: tiny muscles that make the

hairs stand up during “goosebumps”. HAIR PAPILLAE: what is destroyed by

electrolysis, so hair won’t grow back. The HAIR MATRIX is the leading edge of the

papillae. It is actually skin cells (keratocytes) which are rapidly dividing. When they die, the new ones push them out, forming the hair. Hair is just dead skin cells. The HAIR ROOT is just the base of the hair.

The hair matrix is the part of the follicle that is the site of hair growth and the location of the melanocytes that determine hair color.

Hair that goes grey has lost its melanin pigment.

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LAYERS OF THE EPIDERMIS

Stratum corneum (most superficial layer of epidermis)

Stratum lucidum (only in thick skin) Stratum granulosum (cells start to die here) Stratum spinosum Stratum basale (the deepest layer of

epidermis; cells are reproducing only here)

SKIN CANCERThis is the most common cancer in the USA, and its

major risk factor is exposure to ultraviolet light.

1) BASAL CELL CARCINOMA: Cancer of the blood vessels.Almost never metastasizes or crosses the basement membraneLooks like shiny nodules

2) SQUAMOUS CELL CARCINOMA25% of all cancersWill metastasize if not treated.

3) MELANOMA: cancer of the melanocytes of the epidermisHighly metastatic.Asymmetrical, sharp but irregular borders and edgesNot uniform in color.

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BURNS

FIRST DEGREE: Minor burn to the epidermis; sunburn

SECOND DEGREE: Dermis separates from epidermis; blister

THIRD DEGREE: Hypodermis is burned. (most severe type of burn)

KELOID: Thick, red, painful scars HEMANGIOMA: enlargement of the lining of

blood vessels, and is treated with lasers6

Piebaldism: a rare autosomal dominant disorder of melanocyte development, causing a congenital white patch of hair.

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GROSS ANATOMY OF BONES

TWO TYPES OF BONE TISSUE Compact bone – 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

Osteomalacia: Rickets caused by lack of Vitamin D

Achondroplasia: type of dwarfism Chondromalacia: cartilage rubbing off, usually

under the patella of active people.8

CLASSIFICATION OF FRACTURES

SIMPLE (CLOSED)Skin is not brokenMay just require a cast

COMPOUND (OPEN)Bone has broken through the skin Increased chance of infections, which can be

life-threatening.Requires surgery, hospitalization and IV

antibiotics

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CLASSIFICATION OF FRACTURES INCOMPLETE

Only one side of the bone is broken

COMPLETEBoth sides of bone is broken

DISPLACED: The bone fragments don’t line upProduces new and abnormal bone arrangements

Non-DISPLACED: The bone fragments stay lined up

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TYPES OF FRACTURES

COMMINUTED: The most serious of the closed fractures; bone shatters into many small pieces. Bone graft might be needed.

SPIRAL: Bone was twisted. GREENSTICK: most common in children COMPRESSION: bone is crushed, like the vertebrae

in osteoporosis. STRESS: least serious, get tiny, almost invisible

breaks. COMPOUND (open) FRACTURES: Bone breaks and

goes through skin. Increased chance of infections, which can be life-threatening.

SIMPLE (closed) FRACTURES: Skin is not broken. PATHOLOGICAL FRACTURE: When the bone

(especially the hip bone of someone with osteoporosis) breaks first, then the patient falls.

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CLASSIFICATION OF JOINTS: TWO WAYS 1. What type of movement does the joint allow?

No movement, limited movement, free movement

2. What tissue joins the bones?Fibrous Joints

Fibrous connective tissue (dense regular CT) suture, tooth, ligament

Cartilaginous Joints Fibrocartilage (vertebral discs, pubic symphysis) Hyaline cartilage, no capsule (epiphyseal plate, costal cart)

Synovial: Hyaline cartilage with a capsule

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TYPES OF MOVEMENT Synarthrotic

immoveable, allows no movement

Amphiarthrotic

allows only limited movement

Diarthrotic

freely moveable

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Cartilaginous Joints

A cartilaginous joint is two bones joined by cartilage. The cartilage is either fibrocartilage or hyaline cartilage.

Fibrocartilage joints (symphyses) are amphiarthrotic (slightly moveable). Examples are intervertebral discs and the pubic symphysis

Hyaline cartilage joints (synchondroses) are synarthrotic (immovable). Examples are epiphyseal plates and costal cartilages

Therefore, one type of cartilaginous joint is slightly moveable (fibrocartilage) and one type of cartilaginous joint is immovable (hyaline)

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LIGAMENTS

• The joint capsule alone is not strong enough, so there are reinforcing LIGAMENTS, which provide most of the strength of holding the bones to bones. They are dense regular connective tissue.

• In the knee joint, the collateral ligaments are the main ligaments that keep the knee from moving medially to laterally.

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LIGAMENTS

Ligaments take a long time to heal if torn because they do not have blood vessels of their own, like bones do. They already have enough fibroblasts and collagen, though, so they eventually can heal. It is better to break a bone than tear a ligament because bones have a better blood supply and heal faster.

SPRAINS: are tears in a ligament, and are fairly serious. When a ligament is sprained, it can take 6 months to heal, and may even need surgery. Even with a partial tear, you have to be careful.

STRAIN: is a tear in a muscle, and is not as bad because it has good circulation and heals faster. If you can walk on it and it heals in a couple of days, it’s a strain. 16

SKELETAL MUSCLE

For skeletal muscle to contract, a neuron must first release a chemical called acetylcholine onto the region known as the endplate.

Calcium is also needed for muscle contraction. The nerve signal is called an ACTION

POTENTIAL. It causes a release of calcium from the muscle

fiber, which causes contraction.

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Don’t confuse these terms!

MUSCLE FASCICLE: a group of muscle fibers, surrounded by perimysium.

MUSCLE FIBER: a single muscle cell

MYOFIBRIL: a long organelle inside a muscle fiber, contains actin and myosin myofilaments.

MYOFILAMENTS: these are proteins, and there are two types: actin (with troponin and tropomyosin) and myosin. The myofilament is the lowest level of organization that is composed of actin, myosin, troponin, and tropomyosin proteins.

Therefore, a myofilament is part of a myofibril, which is inside a muscle fiber, which is inside a muscle fascicle.

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MECHANISM OF CONTRACTIONThe Sliding Filament Theory

Contraction results as the myosin heads of the thick filaments attach like hooks to the thin actin filaments at both ends of the sarcomere and pull the thin filaments toward the center of the sarcomere.

The myosin head is like a hook with a hinge. After a myosin head pivots at its hinge, it draws the actin closer, then lets go, springs up again to grab the actin filament again, pulls it closer, and it keeps repeating this until the entire actin filament has been drawn in as far as it can go.

The sites where the myosin heads hook onto the actin are called cross-bridges.

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MUSCLE CONTRACTION

TROPONIN is a complex of three proteins. TROPOMYOSIN is a single protein.

Both troponin and tropomyosin cover the ACTIN filament when the muscle is relaxed.

PHRENIC NERVE: controls contraction rate of the diaphragm.

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ATP AND CREATINE PHOSPHATE

What do we do when we run out of ATP? Muscle fibers cannot stockpile ATP in preparation for

future periods of activity. However, they can store another high energy molecule

called creatine phosphate, which is the storage form of ATP.

Creatine phosphate is made from the excess ATP that we accumulate when we are resting.

During short periods of intense exercise, the small reserves of ATP existing in a cell are used first.

Then creatinine phosphate is broken down to produce ATP.

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MUSCLE DISEASE

MUSCULAR DYSTROPHY Genetic lack of the protein DISTROPHIN. The muscle cell won’t contract.

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BONE CELLS

Osteoblast (makes bone) Osteocyte (mature bone cell) Osteoclast (reabsorbs bone)

Bone Infection = osteomyelitis

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OSTEON

Osteon: The functional unit of compact bone. osteocytes The mature bone cells which are

trapped in the matrix and help to maintain it lacunae The pockets or cavities in which the

osteocytes live and are trapped canaliculi The “tiny channels” for the legs of

each star-shaped osteocyte. Canuliculi allow for diffusion of nutrients and wastes to the other osteocytes.

lamellae The circular and concentric layers formed by the osteocyte matrix because they sit next to each other in circles.

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ARTHRITIS

OSTEOARTHRITIS: common in older people. The articular cartilage begins to break down, and bone spurs start to grow.

RHEUMATOID ARTHRITIS: It’s an autoimmune disease where body attacks and destroys the cartilage in synovial joints. It is NOT known for having spurs, like osteoarthritis.

GOUTY ARTHRITIS (gout). Caused by eating too much red meat or protein. The breakdown product is urea, and acid, which causes uric acid crystals in the cooler areas of the body, especially big toes.

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TYPES OF GLIAL CELLS

1. OLIGODENDROCYTES (“few branches”). They are found in the CNS, are very large and complex cells. Oligodendrocytes form MYELIN SHEATHS. This sheath is a covering around an axon to speed up the nerve conduction.

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TYPES OF GLIAL CELLS

2. SCHWANN CELL is another cell that forms myelin sheaths, but in the PNS. Each cell only forms one myelin sheath.

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The action potential jumps from one Node of Ranvier (the bare area) to the next Node, skipping the myelin that is between the bare areas). This speeds up the overall nerve conduction.

Therefore, a myelinated axon conducts impulses faster than an unmyelinated axon.

Why aren’t all neurons myelinated? Isn’t it good for everything to be faster?

No, myelin is a living cell, so it uses nutrients! We’d better save the myelin for where we need

it.28

MULTIPLE SCLEROSIS is an autoimmune disease where the oligodendrocytes (the myelin sheaths) are destroyed (demyelination), interfering with the neuron functions in the CNS. Oligodendrocytes cannot regenerate.

MS is the most common neurological disease of young adults. Starts to manifest in late teens and early 20’s.

It progresses to paralysis and sometimes death. One in 1000 people get it. There are treatments, but

no cure.

NEURON DISEASE

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V. TRIGEMINAL NERVE

This is the main sensory nerve of the face. It has a large branch that passes through the foramen ovale of the skull. It has three parts.

When a dentist numbs the lower teeth, he injects the mandibular branch. For the upper teeth, he injects the maxillary branch.

The superior branch is the opthalmic branch. Problems with CN-V are called TRIGEMINAL

NEURALGIA, which is excruciating pain in the face from nerve inflammation.

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VII FACIAL NERVE This is the main motor nerve of the face. It

innervates the muscles of facial expression. A person who cannot blink or smile may have

damage to this nerve. Someone with a damaged facial nerve

can not easily taste sweet, sour, or salty substances.

It also supplies parasympathetic innervation to most salivary glands.

BELL’S PALSY is damage of the facial nerve causing paralysis on one side. The nerves swell from infection by herpes simplex virus, but only the motor nerves are involved, not the sensory, so it’s painless. Needs to be distinguished from a stroke. . VIDEO

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IX: GLOSSOPHARYNGEAL

Along with CN X, the Glossopharyngeal nerve carries information from the baroreceptors in the head and neck to the brainstem.

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X. VAGUS NERVE

The only cranial nerve that “Wanders” into thorax and abdomen

Table 14.2

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PRE-CENTRAL GYRUS There is a precise map of the different body parts in

the pre-central gyrus. This map is called a motor homunculus (Latin: little

man) Not all body parts are equally represented by cell

density in the motor area in proportion to their size in the body.

Lips, parts of the face and hands enjoy especially large areas of cells in the motor area.

The face region of the homunculus is large so we can have many facial expressions. The hands and tongue are large, indicating that we have many fine motor skills in those areas as well.

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SENSORY TRACTS

Sensory signals go to the brain via a TRACT.

A tract is a collection of axons inside the central nervous system.

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VISCERAL (“ORGAN”) SENSES

A visceral nerve innervates involuntary effectors (smooth muscles in organs).

A somatic nerve innervates voluntary effectors (skeletal muscle).

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BRAIN DISEASESHYDROCEPHALY

This is usually congenital, caused by a blockage of the cerebral aqueduct. So the CSF is made but can’t leave, and the brain gets expanded.

MENINGITISThis is when the meninges become

infected. Can be caused from virus (not that bad) or bacteria (can be fatal). The main symptom is a headache.

ENCEPHALITISThis is infection of the brain. It can be

caused by mosquito-borne illnesses, or bacteria. Treatment is to remove a piece of the skull bone to allow the swelling.

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AUDITORY ASSOCIATION AREA The auditory association area contains two

special regions BROCA'S AREA is a region of the brain that

allows for speech. Injury (stroke) in this location causes impairment

of speaking certain words. They know what they want to say, they just cannot get the words out. Not being able to speak at all is called aphasia.

WERNICKE’S AREA is the region of the brain that allows understanding of words.

It does not affect a person’s speech. They can say what they want to, but they cannot comprehend someone else’s speech.

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Carpel Tunnel Syndrome

PERIPHERAL NERVE DAMAGE

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PERIPHERAL NERVE DAMAGE

SCIATICA Inflamed sciatic nerve

NEUROMA Inflamed nerve in the ball of the foot Often caused from wearing high heels

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EYE DISORDERSPRESBYOPIA (“old eyes”). Occurs around age 45-50. The lens

cannot accommodate.HYPEROPIA (far-sighted) eyes are too short; MYOPIA (nearsighted)CATARACTS. Clouding of the lens.RETINAL DETACHMENTASTIGMATISM is when the cornea has an irregular shape. MACULAR DEGENERATION: the most common cause of

blindness in the US. It’s due to bleeding in the eye, causing scar tissue.

DIABETIC RETINOPATHY: the high sugar levels destroy the photoreceptors in the retina.

GLAUCOMA: increased pressure within the anterior chamber of the eye. It leads to blindness.

AMBLYOPIA = Lazy Eye. 41

EAR DISORDERS

VERTIGO Inflammation of the semi-circular canals. Gives you a sense of motion when you’re not

moving = (dizziness).

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HEMATOCRIT A quick screening test for anemia is the

hematocrit. A drop of blood is drawn up a small glass capillary

tube and the tube is centrifuged to pack the red blood cells at the bottom with the plasma on top.

The hematocrit is the ratio of packed red blood cells to total blood volume.

Normal is 46% for men and 38% for women.

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BLOOD DISEASES Anemia is when the blood’s capacity for carrying

oxygen is diminished. It can be caused by blood loss, deficiency in iron, B12, or folic acid, RBC destruction, or a genetic defect of hemoglobin in the RBCs.

ANEMIA: Causes of anemia include lack of iron, hemorrhage, lack of vitamin B12 (needed for cell division).

Leukemia is cancer of the stem cells, results in too few NORMAL WBCs, although overall WBC count is high.

Thalassemia is a form of anemia. The RBCs have abnormal hemoglobin.

Sickle cell disease is present in African Americans more than in other groups, and is always characterized by sickled erythrocytes.

Thrombocytopenia: too few platelets, and blood doesn’t clot properly.

A thrombus is a blood clot in a vessel. An embolis is a thrombus that travels in the blood

stream. Immunotherapy: form of cancer treatment that takes blood

cells from a patient and fuses the blood with an antibody that is specifically designed to seek out and destroy the cancer cell.

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The left ventricle is the largest chamber. It pushes the blood out of the aorta to be distributed to the rest of the body. Therefore, it is the chamber which has the greatest pressure upon contraction.

LA

LV

IVC

Pulmonary artery

Aorta

Pulmonary vein

SVC

RA

RV

Tricuspid valve

Bicuspid valve (Mitral)

Pulmonary semilunar valve

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HEART BEATS The heart does not need a nerve to stimulate it to contract,

rather, specialized heart cells can spontaneously start an action potential that spreads to depolarize the rest of the cardiac muscle cells.

First the Sinoatrial (SA) node starts an action potential which causes the atria to depolarize.

This depolarization will then reach the AV node at the bottom portion of the right atrium and there is a delay here because these cells are so small in diameter.

Another delay in the transmission of the depolarization at the bundle of His (AV bundle) because these special heart cells travel through the atrioventricular septum which is non-conductive fibrous connective tissue.

Next, the depolarizing event travels through the left and right bundle branches, found in the interventricular septum, to finally arrive at the Purkinje fibers in the ventricular myocardium. 46

HEART BEATS

The left and right ventricles contract at the same time = SYSTOLE.

When the ventricles are relaxed = DIASTOLE.

At which stage do the atria contract? Diastole.

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HEART DISORDERS PERICARDITIS: inflamed outer layer of

heart. ENDOCARDITIS: Bacteria enter

bloodstream HEART MURMUR: The valve leaks PROLAPSED VALVE is more serious.

Mitral valve is most likely to prolapse because it pumps the hardest. Might need artificial valve.

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HEART DISORDERS ARRHYTHMIA = problem with the SA or AV node improper

heart beat. Treatment is medicine or a pacemaker. ANGINA = Not enough blood to the heart wall severe pain

(angina pectoris) MYOCARDIAL INFARCTION = Complete blockage not

enough O2 to that area = ISCHEMIA that part of heart muscle dies.

Angioplasty is a surgical procedure to clean out a clogged artery.

Aspirin reduces blood clot formation. Nitroglycerine dilates the coronary arteries so more blood

can get in.

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HEART DISORDERS ATHEROSCLEROSIS is caused from eating fatty food = build-up of fat inside artery narrowing of artery. VENTRICULAR FIBRILLATION: (the ventricles are

unable to pump blood efficiently due to rapid, random contraction of cardiac muscle fibers). The muscle doesn’t contract as a unit. Treatment is defibrillate with electric shock

Congestive heart failure is progressive weakening of the heart as it fails to keep up with the demands of pumping blood.

CORONARY BYPASS: Take another blood vessel graft (from thigh) and go around the blockage.

A ‘blue baby” has low oxygen levels in the blood that may be due to failure of the foramen ovale to close at birth. 50

BLOOD VESSELS Saphanous vein is often used to bypass a

damaged coronary artery in coronary bypass surgery. It is the most likely vein to become varicose anyway.

Facial vein: squeezing pimples, and nose piercings in the “danger triangle” of the face can spread infection through the facial vein into the dural sinuses of the brain.

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DISORDERS OF LYMPH SYSTEM

Hodgkins disease: Cancer of the lymph nodes; many enlarged lymph nodes that do not feel tender

Mononucleosis: Epstein Barr virus attacks B lymphocytes and causes inflammation of lymph vessels.

EDEMA is the accumulation of excess tissue fluid in loose connective tissue.

Lymphangitis: lymph vessel inflammation; usually from infection.

BUBO is an infected lymph node that contains a large number of pathogens that are trapped in the node but not destroyed.

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RESPIRATORY DISORDERS

LARYNGITIS: inflamed vocal cords (↓ sound production). Scar Tissue Nodules: Singers can this; may

require surgery.

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RESPIRATORY DISORDERS INFLUENZA This is the “flu” caused by a virus. This is

what you are vaccinated against when you get the flu vaccine.

LUNG CANCER: the #1 or #2 most deadly form of cancer. 85% of lung cancer is caused from smoking.

RESPIRATORY DISTRESS SYNDROME: premature babies that don’t have enough surfactant.

PNEUMOTHORAX (COLLAPSED LUNG) from a hole in the pleura (injury from broken rib, knife), it’s like opening the stopper; air flows in through the hole, and the lungs don’t inflate.

PLEURISY: Infection of the pleura; The rubbing together of inflamed pleural membranes that produces a stabbing pain in the chest with every breath; it feels like a broken rib. 54

INSPIRATION

The diaphragm and the external intercostals are the muscle group that produces inspiration.

The diaphragm and the internal intercostals are the muscle group that produces expiration.

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RESPIRATORY DISORDERS ASTHMA: In allergic conditions, bronchioles

will constrict, blocking air flow to the lungs. CHRONIC OBSTRUCTIVE PULMONARY

DISEASE (COPD) It is one of two conditions:

CHRONIC BRONCHITIS: inflammation of the bronchi, produces mucous, the openings become smaller = obstructed.

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. Emphysema is characterized by a person with a large, “barrel” chest.

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TOOTH DISORDERS

CAVITY: Bacteria eat away at the enamel. ROOT CANAL: If the cavity extends into the pulp

cavity. GINGIVITIS: Bacteria cause inflammation of the

gingiva. PERIODONTITIS: gingiva pulls away from the tooth

and extends down to the periodontal ligament. This is the major cause of tooth loss.

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GI DISORDERS GASTRIC ULCER: Bacterial infection can

erode the stomach lining. DIVERTICULITIS: a small pouch in the large

intestine becomes inflamed. COLITIS: inflammation of the colon. COLON CANCER: The #1 most deadly

cancer (kills more people) because it metastasizes and there are no symptoms.

COLONOSCOPY: Used to looks for POLYPS, which are pre-cancerous growths Polyps might cause blood in the stool.

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GI DISORDERS

HEMORRHOIDS are varicose veins along the rectum.

HEPATITIS: Infection of the liver = (can be deadly)

CIRRHOSIS: liver cells die; often from alcoholism.

JAUNDICE: This is not a disease; it is a symptom of liver disorder. It first shows up in the sclera of the eye because it is white there. 59

STOMACH CELLS

PARIETAL CELLS in the stomach secrete hydrochloric acid and digestive enzymes which kill bacteria in the stomach.

They also secrete intrinsic factor, which is needed to absorb vitamin B12. Lack of B12 causes pernicious (megaloblastic) anemia.

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. 60

Finished!Congratulations!

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