各论II 13、泌尿系统生理学 梁华为.pdfVIP

Urinary Concentrating Mechanism 尿液浓缩的机制 A B C The Countercurrent Theory Countercurrent Multiplication 逆流倍增 The Countercurrent Theory Countercurrent Exchange 逆流交换 Permeability of the Tubular System H O NaCl Urea 2 Thick ascending limb _ Actively transport _ Thin ascending limb _ + + Thin descending limb ++ _ _ Distal tubule + ADH Actively transport _ Cortical collecting duct + ADH Actively transport _ Inner medullary + ADH Actively transport ++ collecting duct Countercurrent Multiplier in the Kidney 肾脏中的逆流倍增器 Loop of Henle Establishing of Osmotic Gradient of the Renal Medulla 肾髓质渗透梯度的建立 Maintenance of the Osmotic Gradient in the Medulla 髓质渗透梯度的维持 The vasa recta (直小血管): Countercurrent Exchanger Formation of Concentrated or Dilute Urine 浓缩尿和稀释尿的形成 In the presence of ADH Collecting duct permeable to water → excretion of a concentrated urine In the absence of ADH Collecting duct impermeable to water →excretion of a diluted urine Factors that affect the concentration and dilution of the urine 影响尿液浓缩和稀释的因素 1) Damage of renal medulla Resulting in an impairment of the concentrating ability 2) Loop diuretics + + - such as frusemide, inhibiting the Na / K / 2Cl cotransport system in the t