Urine 3

ajv09c's version from 2015-04-13 14:54


Question Answer
Explain what is the driving force to glomerular filtration Glomerular filtration is governed by the balance between hydrostatic pressure and colloid osmotic pressure on either side of the capillary and an efferent arteriole with a smaller diameter than afferent arteriole
hydrostatic pressure fluid pressure
colloid osmotic pressure osmotic pressure resulting from suspended proteins
Explain how to calculate the net filtration pressure at the glomerulusdifference between the net hydrostatic pressure and the blood colloid osmotic pressure acting across the glomerular capillaries. nfp = nhp-bcop
Explain how the glomerular filtration rate (GFR) is regulatedThree interacting levels of control Autoregulation (local level) Hormonal regulation (initiated by kidneys) Autonomic regulation (by sympathetic division
creatinine clearance testis used to estimate gfr more accurate test inulin
Autoregulation of the GFR local level control Maintains GFR despite changes in local blood pressure and blood flow By changing diameters of afferent arterioles, efferent arterioles, and glomerular capillaries
Reduced blood flow or glomerular blood pressure triggersDilation of afferent arteriole Dilation of glomerular capillaries Constriction of efferent arterioles
Autoregulation of the GFR Rise in renal blood pressureStretches walls of afferent arterioles Causes smooth muscle cells to contract Constricts afferent arterioles Decreases glomerular blood flow and reduces GFR
Hormonal Regulation of the GFR By hormones of the: Natriuretic peptides (ANP and BNP) Renin–angiotensin-aldosterone system
If there is an increase in blood volume GFR automatically increases to promote fluid loss Hormonal factors further increase GFR, accelerating fluid loss in urine
Hormonal Regulation of the GFR Natriuretic Peptides Are released by the heart in response to stretching walls due to increased blood volume or pressure Atrial natriuretic peptide (ANP) is released by atria Brain natriuretic peptide (BNP) is released by ventricles Trigger dilation of afferent arterioles and constriction of efferent arterioles Elevate glomerular pressures and increase GFR