AP 4.28 Lecture

kylerigonan's version from 2015-05-10 22:55


Question Answer
what are the 4 parts of the nephronDCT, PCT, Renal Corpuscle and Loop of Henle
what is the role of DCTChange water reabsorption based on hormones
What is the role of PCTReabsorption
what is the role of loop of Henlesalty medulla and diluted filtrate
what is the role of renal corupuscle filtration
what are the 2 capillary beds at nephronglomerulus and peritubular capillaries (located around PCT and DCT)
what hormones stimulate the DCT permeability ADH and Aldosterone
what hormones inhibits the DCT permeabiltyANP
what is inside filtrate? everything in plasma except proteins due to size, metabolic wastes and unneeded materials
what is the 3 mechanisms of urine formation? (1) glomerular filtration (2) tubular reabsorption (3) secretion
mechanism of urine formation by glomerular filtrationfrom glomerular capillary with the use of pressure to move material out to capsular space.
mechanism of urine formation by tubular reabsorptionselectively move material from filtrate into blood
mechanism of urine formation by secretionblood into filtrate. secretion in order for pH balance. intercalated cells in collecting duct either absorbed/secreted
what are the favorable and opposing pressure of filtration?F:Hydrostatic pressure in the glomerulus 55mmHg... O: Osmotic pressure in the colloid 30mmHg and Hydrostatic pressure in the capsule ~15mmHg
NFPNet filtration pressure
GFR Glomerular Filtration Rate.. Hpw much filtrate formed per min (vol/time)
what are the 3 factors that effect filtration rate at the capillary bed?1) total surface area available for filtration 2) filtration membrane permeability 3) net filtration pressure
what are the 3 layers that separate blood from filtrate 1) fenestrated endothelium 2) basement membrane 3) podocytes/visceral layer of glomerular capsule
what are the dangers of too high or too low GFRToo high will not allow enough time to reabsorb necessary materials and too low GFR will cause body to reabsorb EVERYTHING (like wastes) because filtrate sits too long (less selective)
What are the 3 mechanisms to regulate glomerular filtration1) renal autoregulation 2) neural control 3) hormonal mechanism
what is renal autoregulation?during resting conditions the kidneys will regulate GFR by 2 mechanisms (myogenic mechanism and tubuloglomerular feedback)
what is the myogenic mechanismtargets smooth muscle in the afferent arteriole
what is the effect of a stimuli of high systemic BP vs low systemic BPHigh systemic BP means high for the whole CV system so the effect will be constrict afferent arteriole to slow down BP going into glomerulus=slow down blood flow and less volume of fluid into glomerulus.
what is the tubuloglomerular feedback?2nd renal auto regulator that uses macula densa cells. Macula densa monitors amount of NaCl in the filtrate. When high GFR then filtrate is going through too fast through nephron allowing no time for reabsorption so high NaCl in the filtrate. Macula densa will release chemicals that target afferent arterioles to constrict.. If low NaCl then low GFR and macula densa does not respond and its already dilated
what are the neural controls that regulate glomerular filtrationAre extrinsic controls that are OUTSIDE kidneys and not in resting.
what hormones are released in the neural control of glomerular filtrationNorepinephrine release by symp. Ns and epinephrine from the adrenal medulla. will target afferent arterioles to constrict and filtration is inhibited resulting in a lower GFR.. **sympathetic NS will also activate renin-antiontensin = increase GFR
Hormonal mechanism to regulate glomerular filtrationJuxtaglomerular cells are smooth muscle cells in afferent arteriole and produces renin which causes angiotensin II to be made.
what is the result of Angiotensin II in kidneysAngiotensin II is a systemic vasoconstritor and will also cause adrenal cortex to release aldosterone that brings in more salt into blood resulting in higher BP = higher hydrostatic pressure in glomerulus = higher NFP = Higher GFR
what is the countercurrent exchanger?descending vaso recta allows for Na to be absorbed into the blood and water out to medulla. Ascending vasa recta allows for Na out to medulla and water back into blood.
what is the importance of countercurrent exchangerwithout it then Na would leave, we need Na in medulla for a Na gradient