There are two separate transport systems: Blood Lymph CIRCULATION A transport system which links the cells of an organism with its environment. Organisms which are small and have their cells in direct contact with their environment do not require a transport system. There are two separate transport systems: Blood Lymph

Blood Functions: (1) transport materials to and from the body cells (2) distribute heat in the body (3) provides defense against invading organisms (4) serves as a regulator in the body

There are two major forms of circulatory systems: Open circulatory system: Blood is contained in blood vessels for only part of the time. While outside the vessels it filters through the body tissue. The blood in such a system does not transport oxygen. It is slow and inefficient, and found only in smaller organisms. Closed circulatory system: Blood is always contained in the blood vessels. The blood in such a system transports oxygen. It is fast and efficient, and found in large complex organisms.

Major organs of the human circulatory system: (1) Blood (2) Blood Vessels (3) Heart

Blood An adult human has between 4 and 6 liters of blood in his or her body. Composition - the blood is made up of two major divisions: (i) Plasma (55%) - solvent (ii) Formed elements (45%) - solute

Plasma This is the liquid component of blood. It is a clear, straw-colored liquid composed of : (A) water (90%) (B) dissolved substances (10%) ---> includes salts, glucose, amino acids, fatty acids, vitamins, enzymes, hormones, cellular wastes, and proteins. Three major forms of protein: (1) fibrinogen - important in blood clotting (2) globulin - body defense (3) albumin - helps regulate water balance in the blood. (osmotic balance)

Formed Elements This is the solid component of blood. It consists of red blood cells (RBCs), white blood cells (WBCs), and platelets.

Red Blood Cells / Erythrocytes 5 million per cubic millimeter 30 trillion per adult produced in the bone marrow disc shaped, possessing no nuclei life span of 120 days 2 million destroyed per second. New ones are produced at the same rate. dead ones are removed from circulation by the liver and spleen

Contain the protein hemoglobin which combines with oxygen to form oxyhemoglobin. This occurs at the lungs. Transports carbon dioxide from body cells to the lungs. Does this in two ways: (A) CO2 combines with hemoglobin to form carboxyhemoglobin (B) CO2 combines with water found inside the cell one disease associated with the RBC is anemia. This is a condition caused by either a lack of hemoglobin, or too few RBCs.

Symptoms of anemia include: (1) dizziness (2) weakness (3) pale color * Sickle-cell anemia is a hereditary disorder caused by an abnormal form of hemoglobin. The cells are sickle-shaped, and therefore carry little O2. They tend to become clogged in the blood vessels.

White Blood Cells / Leukocytes 8000 per cubic millimeter 60 billion per adult produced in the bone marrow and lymphatic tissue larger than RBCs and contain a nucleus defend body against disease in 2 general ways: (i) engulf (eat) bacteria (ii) produce antibodies there are 5 different types can move out of blood vessels into body tissue

Increase in number at times of infection (up to 30,000 or more per cubic millimeter) One disease associated with the WBC is leukemia. This is cancer of the blood and is caused by abnormally high levels of WBCs.

Platelets 300,000 per cubic millimeter 1.5 trillion per adult produced from bone marrow when bits of cytoplasm pinch off from larger cells within the marrow. These are cell fragments. They contain no nucleus. Play a major role in blood clotting.

Blood Counts as a Diagnostic Tool low RBC count (below 5 million per cubic millimeter) indicates anemia high WBC count (30,000 per cubic millimeter) indicates infection in the body abnormally high WBC count with ever increasing numbers indicates leukemia