Chapter 18 - The Circulatory System : Blood Flashcards
- Identify at least two each of the transport, protective, and regulatory functions of the circulatory system.
Transport:
- The blood carries oxygen from the lungs to all of the body’s tissues, while it picks up carbon dioxide from those tissues and carries it to the lungs to be removed from the body.
- it picks up nutrients from the digestive tract and delivers the, to all the bodies tissues.
- it carries metabolic wastes to the kidneys for removal.
- it carries hormones from endocrine cells to their target organs.
- it transports a variety of stem cells from the bone marrow and other origins to the tissues where they lodge and mature.
Protection:
- The blood plays several roles in inflammation, a mechanism for limiting the spread of infection.
- white blood cells destroy microorganisms and cancer cells.
- Antibodies and other blood proteins neutralize toxins and help to destroy pathogens.
- Platelets secrete factors that initiate blood clotting and other processes for minimizing blood loss.
Regulation:
- By absorbing or giving off fluid under different conditions, the blood capillaries help to stabilize fluid distribution in the body.
- By buffering acids and bases, blood proteins help to stabilize the pH of the extracellular fluids.
- Shifts in blood flow help to regulate body temperature by routing blood to the skin for heat loss or retaining it deeper in the body to conserve heat.
- What are the two principle components of the blood?
Two major components of the blood are plasma and formed elements which consists of cells and cell fragments including the red blood cells, white blood cells, and platelets.
3.List the three major classes of plasma proteins. which one is absent from the blood serum?
Albumin, Globulins, and Fibrinogen. Fibrinogen is absent from the serum.
- Define the viscosity and osmolarity of the blood. Explain why each of these is important for human survival.
Viscosity is the resistance of a fluid to flow, resulting from the cohesion of its particles. It’s the thickness or stickiness of the fluid. It is important in circulatory function because it partially governs the flow of blood through the blood vessels. An RBC or protein deficiency reduces viscosity and causes blood to flow too easily, whereas as excess causes blood to flow too sluggishly.
Osmolarity is the total molarity of dissolved particles that cannot pass through the blood vessel wall. In order to nourish surrounding cells and remove their wastes, substances must pass between the bloodstream and tissue fluid through the capillary walls. If blood osmolarity is too high, the bloodstream absorbs too much water. This raises the blood volume, resulting in high blood pressure and a potentially dangerous strain on the heart and arteries. If its osmolarity drops too low, too much water remains in the tissues. They become edematous (swollen) and the blood pressure may drop to dangerously low levels because of the water lost from the bloodstream.
- What does hemopoiesis mean? After birth, what one cell is the starting point for all hemopoesis?
Hemopoiesis is the production of blood, especially its formed elements. The first hempoietic tissues of the human embryo form in the yolk sac.
- What are the two principle components of the blood?
Two major components of the blood are plasma and formed elements which consists of cells and cell fragments including the red blood cells, white blood cells, and platelets.
3.List the three major classes of plasma proteins. which one is absent from the blood serum?
Albumin, Globulins, and Fibrinogen. Fibrinogen is absent from the serum.
- Define the viscosity and osmolarity of the blood. Explain why each of these is important for human survival.
Viscosity is the resistance of a fluid to flow, resulting from the cohesion of its particles. It’s the thickness or stickiness of the fluid. It is important in circulatory function because it partially governs the flow of blood through the blood vessels. An RBC or protein deficiency reduces viscosity and causes blood to flow too easily, whereas as excess causes blood to flow too sluggishly.
Osmolarity is the total molarity of dissolved particles that cannot pass through the blood vessel wall. In order to nourish surrounding cells and remove their wastes, substances must pass between the bloodstream and tissue fluid through the capillary walls. If blood osmolarity is too high, the bloodstream absorbs too much water. This raises the blood volume, resulting in high blood pressure and a potentially dangerous strain on the heart and arteries. If its osmolarity drops too low, too much water remains in the tissues. They become edematous (swollen) and the blood pressure may drop to dangerously low levels because of the water lost from the bloodstream.
What does hemopoiesis mean? After birth, what one cell is the starting point for all hemopoesis?
Hemopoiesis is the production of blood, especially its formed elements. The first hempoietic tissues of the human embryo form in the yolk sac.
- Describe the size, shape, and contents of an erythrocytes, and explain how it acquires its unusual shape.
An erythrocyte is a discoidal cell with a bio concave shape. A thick rim and a thin sunken center. It is about 7.5 um in diameter and 2.0 um thick at the rim. RBcs lose their nucleus and other organelles during maturation and are divoid of internal structure. It relies exclusively on anaerobic fermentation to produce ATP.
- WHat is the function of hemoglobin? What are its protein and nonprotein moieties called?
Hemoglobin is the red pigment that gives RBCs its color and name. It plays a role in oxygen and carbon dioxide transport and the buffering of blood pH. Hemoglobin consists of four protein chains called globins. Two are alpha chains and are 141 amino acids long. And the other two are beta chains and are 146 amino acids long. Each chain is conjugated with a nonprotein moiety called the heme group, which binds oxygen to a ferrous ion (Fe2+)
- Define hematocrit, hemoglobin concentration, and RBC count, and give the units of measurement in which each is expressed.
The hematocrit (packed cell volume, PCV) is the percentage of whole blood volume composed of RBCs. In men, it normally ranges between 42% and 52%; in women between 37% and 48%. The hemoglobin concentration of whole blood is normally is 13 to 18 g/dL in men and 12 to 16 g/dL in women. The RBC count is normally 4.6 to 6.2 million RBCs/uL in men and 4.2 to 5.4 million/uL in women. This is often expressed as cells per cubic millimeter (mm3); 1 uL = 1 mm3.
- List the stages in the production of an RBC and describe how each stage differs from the previous one.
Erythropoiesis is the production of erythrocytes.
- process takes 3-5 days.
- involves four major developments:
~ a reduction in cell size
~ an increase in cell number
~ the synthesis of hemoglobin
~ the loss of the nucleus and other organelles
- stages of development of RBC:
~ Hemopoietic stem cell (HSC): here it becomes an erythrocyte
Colony forming unit ( ECFU)which has receptors for the hormone erythropoietin (EPO). EPO stimulates the ECFU to transform into an erythroblast (normoblast).
~ erythroblasts multiply and synthesize hemoglobin. When this task is completed, the nucleus shrivels and is discharged from the cell.
~ the cell is now called a reticulocyte, named for a temporary network (reticulum) composed of ribosome clusters (polyribosomes).
~ reticulocyte sleeve the bone marrow and enter the circulating blood.
~ In a day or two, the last polyribosomes disintegrate and disappear, and the cell is a mature erythrocyte.
- What is the role of erythropoietin in the regulation of RBC count? What is the role of gastroferritin?
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- What happens to each component of an RBC and its hemoglobin
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