2:Transport

Transport: the absorption and circulation of materials throughout an organism

HEART

septum: muscular central wall dividing the mammalian heart into two halves

atria : thin walled upper heart chambers which receive blood pump blood to the ventricles

ventricles: muscular thick walled chambers which pump blood from the heart -- the lower chambers

valves--prevent the backward flow of blood in the heart

** The heart functions as a double pump beating in unison.

Deoxygenated blood--relatively low in oxygen

Oxygenated blood--relatively high in oxygen

** Heartbeat is stimulated by an electrochemical impulse.

pacemaker--in the right atrium --initiates the heartbeat

(Pathway of a Red Corpuscle through the Heart)

1. Inferior & superior vena cava

2. Right atrium

3. valve

4. Right ventricle

5. valve

6. Pulmonary arteries

(BLOOD TO THE LUNGS--GAS EXCHANGE)

7. Pulmonary veins

8. Left Atrium

9. valve

10. Left ventricle

11. valve

12. Aorta

#'s (1-6) deoxygenated #'s (7-12) oxygenated

A = aorta

B = pulmonary arteries

C = pulmonary veins

D = left atrium

E = valve

F = left ventricle

G = right ventricle

H = valve

I = vena cavae

J = right atrium

(areas shaded red have oxygenated blood while those shaded blue have deoxygenated blood)

Some Blood Functions)

1. Transport of needed substances to body cells. (oxygen, amino acids, glucose, fatty acids, glycerol, salts, etc.)

2. Transport of wastes from cells. (urea, water, carbon dioxide in the form of the bicarbonate ion)

3. Helps to maintain a constant body temperature.

4. Aids the body in fighting disease.

** In general, the blood is a fluid tissue helping to maintain homeostasis for all cells in the body.

(Blood Composition)

Plasma 55% (liquid part of the blood)

Blood Cells 45%

(BLOOD CELL TYPES)

(a.) Red Blood Cells

-- most numerous

-- biconcave disc shaped

-- smaller than white blood cells, larger than platelets

-- no nucleus when mature

-- produced in the red marrow of long bones

-- destroyed in the liver and spleen

-- contain the iron protein compound HEMOGLOBIN whose chief function is to combine with oxygen and carry it to the cells

** Carbon monoxide has 40X the affinity of oxygen for hemoglobin--breathing it may lead to death

(b.) White Blood cells

--largest blood cells--several different types

--about 8,000 per drop of blood

--most are formed in the bone marrow or in the lymph tissue

--most protect the body against diseases by forming antibodies or engulfing bacteria

( 2 Main White Blood Cell Types)

1. Phagocytes-- engulf bacteria and viruses by phagocytosis

--able to leave the bloodstream and move between the cells of the body by squeezing through the capillary walls

2. Lymphocytes--produce antibodies which clump bacterial poisons or bacteria (antigens)

antigens--foreign substances in the body

(c.) Platelets

--smallest blood cells (fragments)

--150,000 to 300,000 per drop of blood

--needed for clotting

(Clotting Process)

Involves a series of enzyme controlled reactions resulting in the formation of protein fibers that trap blood cells and form a clot.

(Blood Vessels)

1. Arteries

--carry blood away from the heart

--usually spurt blood when cut

--all except the pulmonary artery carry oxygenated blood

--thick walled and elastic

pulse: expansion and contraction of the artery walls in response to the heartbeat

2. Veins

--carry blood toward the heart

--contain valves

--closer to the body surface than the arteries

--all except the pulmonary vein carry deoxygenated blood

--thinner, less muscular and elastic than arteries

--depend upon muscle and diaphragm movements for blood flow

3. Capillaries

--most numerous vessels

--connect arteries to veins

--microscopic, one cell thick walls

--site of much exchange between the blood and the intracellular fluid (lymph) by diffusion

4. Lymph vessels

--have walls one cell thick

--present around all body cells

--Lymph composition is similar to that of blood except for the absence of RBC and some plasma proteins.

--chief site of material exchange with the tissues

Major lymph vessels have lymph nodes which contain phagocytic white blood cells which filter bacteria and dead cells from the lymph.

X = lymph nodes

Valves are present in some lymph vessels--aiding in the movement of the lymph. Respiratory movements also aid lymph flow.

(Cardiovascular Diseases)--malfunctions and disorders of the heart and blood vessels

(Some Cardiovascular Disorders)

1. Hypertension (High Blood Pressure)

--caused by a narrowing of the arterioles resulting in an increased resistance to the flow of blood--increases the strain on the heart

Causes implicated:

1. excess sodium intake

2. stress

3. cigarettes (nicotine)

4. saturated fats

5. alcohol & caffeine

6. obesity

7. heredity & aging

No cure--may be treated by medication & diet.

"Silent killer"--millions don't know they have it

2. Angina pectoris

--pain in the chest which radiates into the left shoulder and arm

--occurs especially when physical exertion results in a lack of oxygen supply to the heart muscle

--caused by a reduction of blood supply due to partial blockage(s) of coronary arteries

3. Coronary thrombosis--heart attack

--caused by a blood clot in a coronary artery that stops circulation to part of the heart muscle

--attack is fatal if much heart muscle is involved