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Introduction to the Cardiovascular System - Part 8

Nếu áp lực thủy tĩnh mao mạch 15 mm Hg, áp lực mao mạch oncotic 28 mm Hg, áp lực mô kẽ 5 mm Hg, và áp lực oncotic mô 6 mm Hg (giả định là 1), các lực lượng Starling này sẽ cho kết quả | EXCHANGE FUNCTION OF THE MICROCIRCULATION 183 An increase in tissue fluid volume edema occurs when the rate of fluid filtration exceeds the sum of the rate of fluid reabsorption and lymphatic flow. Edema can occur when increased capillary hydrostatic pressure increased capillary permeability decreased plasma oncotic pressure or lymphatic blockage occurs. Review Questions Please refer to the appendix for the answers to the review questions. For each question choose the one best answer 1. Which of the following mechanisms is most important quantitatively for the exchange of electrolytes across capillaries a. Bulk flow b. Diffusion c. Osmosis d. Vesicular transport 2. Oxygen exchange between blood and tissues is enhanced by a. Decreased arteriolar flow. b. Decreased arteriolar pO2. c. Decreased tissue pO2. d. Decreased number of flowing capillaries. 3. Net capillary fluid filtration is enhanced by a. Decreased capillary plasma oncotic pressure. b. Decreased venous pressure. c. Increased precapillary resistance. d. Increased tissue hydrostatic pres- 4. If capillary hydrostatic pressure 15 mm Hg capillary oncotic pressure 28 mm Hg tissue interstitial pressure 5 mm Hg and tissue oncotic pressure 6 mm Hg assume that Ơ 1 these Starling forces will result in a. Net filtration. b. Net reabsorption. c. No net fluid movement. 5. If capillary filtration is enhanced by histamine during tissue inflammation a. Lymphatic flow will increase. b. Capillary filtration fraction will decrease. c. The capillary filtration constant will be lower than normal. d. Tissue interstitial pressure will decrease. 6. Edema can result from a. Increased arteriolar resistance. b. Increased plasma protein concentration. c. Reduced venous pressure. d. Obstructed lymphatic. SUGGESTED READINGS Duling BR Berne RM. Longitudinal gradients in periar-teriolar oxygen tension. A possible mechanism for the participation of oxygen in local regulation of blood flow. Circ Res 1970 27 669-678. Intaglietta M Johnson .