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11 Cards in this Set
- Front
- Back
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Describe the principal functions of the blood and its mechanisms to maintain homeostasis.
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• Blood is heavier, thicker and more viscous than water. It has a unique quality that contributes to its ability to form solid clots. The primary objective of the blood is to maintain a constant environment for the rest of the body’s tissues. It maintains this homeostasis via its viscosity (thickness), its ability to carry dissolved substances, and its ability to move to all body parts. Blood is responsible for the transportation of oxygen, carbon dioxide, nutrients, heat, waste products, and hormones to and from the cells. It also helps regulate pH, body temp, and cellular water content. It contributes to protection from blood loss and foreign body invasion. Blood is considered a connective tissue b/c almost all of it is made of cells that share many characteristics with other connective tissues in terms of origin and development.
• Blood is composed of both plasma and formed elements. It is carried thru a closed system of vessels pumped by the heart. The average adult body contains approx |
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Identify the four plasma proteins and their chief functions.
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• Albumin – (accounts for 60-80%) – provides thickness to the circulating blood volume; osmotic pressure. Loss of albumin can result in dramatic fluid shifts, edema, hypotension, and even death.
• Fibrinogen – blood clotting. • Prothrombin – blood clotting. • Globulin – (alpha & beta) – made in the liver, act as carriers for molecules, such as fats. Gamma globulins (Ig) are antibodies. |
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Outline the structure and function of the red blood cells, white blood cells, and platelets.
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• RBC – flattened, biconcave disks. At maturity, they have no nucleus and thus cannot reproduce. They are made from stem cells in red bone marrow. They are fragile and wear out quickly; while the liver and spleen destroy old, used RBCs. The lifespan of an individual RBC is about 120 days. Each RBC contains molecules of the compound hemoglobin (Hgb or Hb); which is composed of the iron-containing pigment heme and a protein, globin. As blood passes thru the lungs, the iron in hemoglobin picks up oxygen in a loose chemical combination. When hemoglobin is saturated with oxygen, the blood is bright red. As blood circulates thru the capillaries, the hemoglobin gives its oxygen to various cells of the body and picks up their carbon dioxide.
• WBC – defend the body against disease organisms, toxins, and irritants. WBCs contain nuclei and can move independently in an ameboid fashion. They also assist in repairing damaged tissue. Sometimes they die during this activity and collect with bacteria to |
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Discuss the importance of chemotaxis and phagocytosis in fighting invading organisms.
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Neutrophils push or squeeze thru the capillary wall and rush to the threatened site of infection. They find their way to foreign or damaged tissues by their attraction to certain chemical substances, known as chemotaxis.
The neutrophils ↑ in number and engulf and devour invaders; phagocytosis. |
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Describe the mechanism of blood clotting.
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• Blood clotting protects the body from losing vital plasma fluid and blood cells by sealing off broken blood vessels. Without this action, individuals would not survive even minor cuts and wounds. When a blood vessel is disrupted, platelets break down & cause the release of a chemical, thromboplastin, which interacts with certain protein factors and calcium ions to form prothrombin activator. This activator then reacts with additional calcium ions to convert the plasma protein prothrombin to thrombin. Thrombin then converts the soluble plasma protein fibrinogen into insoluble threads of fibrin. The threads of fibrin form a net to entrap RBCs and platelets to form a clot. This clot acts like a plug in a hole and tends to draw injured edges together.
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Identify the four blood groups and the Rh factors.
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BLOOD GROUPS
• A • B • AB • O Rh FACTORS • Rh + • Rh – |
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Describe the blood groups that are considered the universal donor and the universal recipient and state why this is so.
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• Universal Donor – is O- (O negative).
• Universal Recipient – AB+ (A-B positive) • Each of the four blood types can receive O typed blood. Type AB can receive from any of the four types. Blood types are inherited (genetic) combinations of antigens and antibodies found on the membranes of RBCs. The negative comes from the Rh factor; inherited antigens. A person with Rh + antigens can receive + or – blood of an acceptable type. A person with Rh – antigens cannot receive + blood due to he or she developing antibodies that could cause a severe reaction to subsequent blood transfusions. |
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Describe lymphatic circulation and the filtration role of the lymph nodes.
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The lymphatic system can be thought of as a secondary circulatory system. The lymph vessels contain a clear, colorless fluid called lymph, which is derived from a network of capillaries which collect this clear fluid as it filters through the capillaries of the blood. The lymphatic system provides our immune defenses, filters foreign substances and cell debris from the blood and destroys them; and produces a type of white blood cells known as lymphocytes, which circulate in the blood and lymph vessels. Lymph passes from tiny capillaries to lymph vessels and flows through lymph nodes that are located along the course of these vessels. Cells of the lymph nodes phagocytize, or ingest, such impurities as bacteria, old red blood cells, and toxic and cellular waste. Finally, the lymph flows into either the thoracic duct, a large vessel that runs parallel to the spinal column, or into the right lymphatic duct, both of which transport the lymph back into veins of the shoulder areas where is reenters the general cir
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Describe the circle of Willis and the blood–brain barrier, including the function of each.
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• The circle of Willis (cerebral arterial circle) is formed by the anterior communicating artery, posterior communicating artery, anterior cerebral artery, posterior cerebral artery and internal carotid artery. The circle of Willis is important b/c it allows blood to continue to flow in the brain if there is a blockage in one of the arteries that supplies the circle of Willis.
• Blood-brain barrier (BBB) is an “adaption of the circulation” that protects the brain. Specialized cells in brain capillaries allow only certain substances from the blood to enter the brain. |
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Explain the process of hepatic–portal circulation.
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• It is a subdivision of systemic circulation; an efficient detour in the pathway of venous return, directed at transporting raw materials in the form of carbohydrates, fats, and proteins from the digestive organs and the spleen to the liver. It is unique b/c it begins and ends with capillaries. The capillaries from the stomach, intestine, spleen, and pancreas empty into veins. These veins drain into a common vessel, the portal vein, which leads into the liver.
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Discuss at least three normal changes in the hematologic and lymphatic systems caused by aging.
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1) Stem cells and marrow reserves ↓, causing ↑ vulnerability to problems with clotting, oxygen transport, and fighting infection. Blood volume ↓ due to decreased muscle mass and metabolic rate.
2) Hemoglobin levels ↓; may be secondary to ↓ intake of iron-rich foods. Loss of active bone marrow causes ineffective RBC production. 3) Leukocyte production ↓ which lessens the response to fight infection. Even though, WBC production typically shows no real change, age-related changes in organs of the immune system can result in altered antigen-antibody responses and ↑ incidence of infection. |
