32-1 Circulation

- The circulatory system carries out four main functions:

1. ) Transportation of nutrients and waste
2. ) Transportation of oxygen and carbon dioxide
3. ) Transportation of hormones
4. ) Distribution of body heat

- Components of Blood:

-Plasma:

1. ) Plasma is the liquid component of the blood.
2. ) Plasma is about 60 % of a volume of blood.
3. ) It acts as a buffer, maintaining pH near 7.4.
4. ) Plasma contains nutrients, wastes, glucose, salts, hormones, and proteins.

- System

- Red Blood Cells:

1. ) Red blood cells, also known as erythrocytes, are flattened, doubly concave cells that carry an iron rich protein called hemoglobin.
2. ) Hemoglobin causes blood to turn red in the presence of oxygen; but more importantly hemoglobin molecules in blood cells transport oxygen.
3. ) Red blood cells are continuously manufactured in red marrow of bones.
4. ) Mature erythrocytes lack a nucleus.
5. ) Life-span of an erythrocyte is only 120 days.
6. ) Each second 2 million red blood cells are produced to replace those taken out of circulation.

White blood cells -:

1. ) White blood cells, also known as leukocytes, are larger than erythrocytes, have a nucleus, and lack hemoglobin. They function in the cellular immune response.
2. ) T-cells attack cells containing viruses.
3. ) B-cells produce antibodies.
4. ) White blood cells (leukocytes) are less than 1% of the blood's volume.

Platelets:

1. ) Platelets result from cell fragmentation and are involved with clotting.
2. ) Platelets are cell fragments that bud off megakaryocytes in bone marrow.
3. ) Platelets stick and adhere to tears in blood vessels; they also release clotting factors.

Blood vessels:

1. ) Arteries are blood vessels that carry blood away from heart.
2. ) Arterioles are small arteries that connect larger arteries with capillaries.
3. ) Capillaries are thin-walled blood vessels in which gas exchange occurs.
4. ) Venules are smaller veins that gather blood from capillary beds into veins.
5. ) Veins carry blood from capillaries to the heart.

A-B-O Blood typing:

1. ) Red blood cells have antigens A, B A&B, or nO antigens at all
2. ) The antigens on your reb blood cells determine your blood type
3. ) If blood with a different antigen on it's surface is transfused into your body than antibodies will attack the new red blood cells and clog your blood vessels.

- Rh factor is an additional antigen that is either present "+" or absent "-" from your red blood cells.

The Lymphatic System:

1. ) Water and plasma are forced from the capillaries into intracellular spaces.
2. ) A secondary circulatory system, the lymphatic circulation, collects fluid and cells and returns them to the cardiovascular system.