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Janessa's Questions

2. Name any two factors which regulate blood pressure and describe how they function to accomplish this.

1)Arteries and Veins - Since the arteries are closer to the heart, blood pressure is higher in the arteries than in the veins. The elastic structure of the arteries and the subsequent expansion and contraction contribute to increased blood pressure.

2)Angiotensin - The juxtaglomerular apparatus senses a drop in blood pressure and releases rennin. Rennin catalyzes the conversion of Angiotensinogen to Angiotensin. Angiotensin stimulates the release of Aldosterone from the Adrenal Cortex which causes the kidney to reabsorb sodium into the blood. The reabsorption of sodium increases the osmotic pressure of the blood (make the blood more concentrated) and cause water to move by osmosis back into the blood from the body tissues. ADH is also secreted which causes further reabsorption of water. Reabsorption of water increases the blood volume, which increases blood pressure.

7. Starting at the vena cava and ending at the aorta, name all the structures, vessels and heart chambers, in order, that deoxygenated blood would contact as it travels through the heart on its way to be reoxygenated, and once it has been oxygenated, the path through the heart again on its way back into the body.

Vena Cava Lungs ➔ Right Ventricle ➔ Atrioventricular Valve ➔ Lungs ➔ Semilunar Valve ➔ Left Atrium ➔ Pulmonary Vein ➔ A-V Valve ➔ Left Ventricle ➔ Heart ➔ Semilunar Valve ➔ Aorta

1. Relate the components of blood to their functions

1. Major components of blood -made up of the following things:

a. Plasma - Blood cells are suspended in the plasma. Plasma makes up 55% of the blood. Made up mostly of water (90%) it carries a number of important things like:

i. Fibrinogen - plasma proteins made in the liver involved in blood clotting

ii. Gammaglobulins - plasma proteins made in the liver involved in fighting infections (immunoglobulins = antibodies)

iii. Albumin -plasma proteins that maintain the high osmotic potential of the plasma preventing loss of fluid from the bloodstream to the tissues

iv. Angiotensinogen - Involved in reabsorption of sodium and control of blood volume and blood pressure

v. Nutrients -(glucose, fats and amino acids)

vi. Gases - oxygen and carbon dioxide

vii. Miscellaneous substances - various ions, hormones, and waste materials (eg. urea and ammonia.)

b.) Blood cells - make up 45% of the blood and consists of the following:

i. Red blood cells - Red blood cells, also called erythrocytes, transport oxygen. They are biconcave, , live for 120 days and are produced in the red bone marrow of adults at the rate of about 1.5 million per second. As the blood cells mature they extrude their entire cell contents. (all the cell organelles) and use the increased area to carry hemoglobin. (hemoglobin carries oxygen in red blood cells).

ii. White blood cells - white blood cells defend the body against viruses, bacteria, and other foreign invaders. They do this by engulfing invaders or by producing antibodies. There are 6000 to 9000 white blood cells per cc. of blood. Notice that the white blood cells in the diagram have nuclei

There are two different kinds of white cells: Neutrophils - make up 60-70% of the white cells, produced in the red bone marrow, arrive at the site of an injury, first, are very active in phagocytosis and play a role in wound healing.

Lymphocytes - two kinds of lymphocytes. B cells are produced in the lymph nodes and are involve in antibody synthesis. T cells originate in the thymus and are involved in rejection of foreign tissue (organ transplants) and other immune responses.

iii. Platelets - look like plates, are colorless, round or biconcave, are smaller than red blood cells, play important roles in blood clotting and are produced in the bone marrow.

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