第八章 肾脏排泄功能EXCRETIVE FUNCTION OF KIDNEY 学习 ….pptVIP

Humoral Control of Renal Functions Atrial natriuretic peptides (心房钠尿肽，ANP) Synthesis in the cardiac atrial muscle cell Leading to increased excretion of salt water Its mechanism: Regulation of ANP Release Stretch of the atrium Extracellular fluid volume and blood volume Plasma sodium concentration Renal Clearance血浆清除率 Defined as the volume of plasma required to supply the amount of a substance X to be excreted in urine per unit time Use of Clearance Methods to Quantify Kidney Function UxV =GF – R + E G=GFR F=Filtration concentration Use of Clearance Methods to Quantify Kidney Function Inulin clearance as a measure of glomerular filtration Use of Clearance Methods to Quantify Kidney Function Clearance of para-aminohippuric acid as a measure of renal plasma flow Para-aminohippuric acid (PAH) freely through the glomerulus Almost all the remaining PAH in the plasma is secreted into the tubule Use of Clearance Methods to Quantify Kidney Function Renal clearance as a calculation of tubular reabsorption or secretion By comparison of inulin clearance with clearances of different solutes ? C125ml／minhas reabsorption ? C125ml／minhas secretion Micturition 排尿 Innervation of the bladder and urethra Micturition Micturition Innervation of the bladder and urethra 1) Parasympathetic pelvic nerves盆神经 To cause contraction of the detrusor muscle of the bladder and opening of the internal sphincter 2) Sympathetic hypogastric nerves腹下神经 To induce closure of the internal sphincter 3) Somatic pudendal nerves阴部神经 To induce contraction of the external sphincter Micturition Reflex Micturition occurs when the intravesicular pressure reaches 70 cmH2O via a reflex action 50 0 Pdet, cm H2O 0 volume 300 ml Higher Control of Micturition Inhibitory and facilitatory centers in the cerebral cortex and pons Pathways of Micturition Reflex Micturition reflex 膀胱内尿量达400~500ml→膀胱壁的牵张感受器(+)→盆神经→骶髓的排尿反射初