week 7 lecture 4 Flashcards
what are the function of the kidney?
excretion-metabolic products and foreign substances urea, uric acid and creatinine or drugs
regulation- body fluids, electrolytes and acid-base substance
control- blood pressure
secretion- hormones-erythropoietin and renin
anatomical structure of kidney
slide 6
blood supply to the kidney
renal artery- segmental artery- interlobar artery- arcrutae artery- interlobular artery- afferent arteriole- glomerular capillaries- efferent arterioles- peri tubular capillaries- interlobular veins- actuate veins- interloper veins- renal veins
anatomical differences between the male and female bladder and urethra
detrusor, trigone, internal sphincters, external sphincters,
bulbousurethra gland
function of detrusor muscle
allows pressure build up to signals the brain to urinate
function of trigone
stretch to limit of expansion that signals the brain to urinate
function of internal sphincters
allows involuntary control to prevent urination
function of external sphincters
voluntary control that prevent urination
function of bulbourethral gland
secrete lubricating fluid to the sperm to promote survival
nephron structure
glomerulus-bowman capsule-PCT- descending and ascending loop of Henle- DCT and collecting duct
cell types and location in the kidney and which are rich in mitochondria
epithelial cells in PCT and Loop- rich in mitochondria
principal cell- low in mitochondria
intercalated cell- rich in mitochondria
types of nephron, their features and ratio of occurence
superficial nephron and juxtamedullary
occurrence is 10:1 ration
why cortex granular while medulla striated
close packing of the glomerulus in the superficial nephron makes it have a granular appearance
constituents of juxtaglomerular apparatus and function
juxtaglomerular cells- regulates the blood pressure by secreting renin
macula Densa-GFR regulation through tubulo-glomerular feedback mechanism
extraglomerular messangial cells
glomerular filtration features adaptations
presence of fenestration, basal membrane, slit and slit diaphragm
diameter of the slit diaphragm
70nm
mechanism of glomerular filtration pressures
hydrostatic pressure from the aorta forces the plasma fluid out against the oncotic pressure and the hydrostatic pressure of the Bowman’s Capsule fluid
how to calculate the net ultrafiltration pressure
net ultrafiltration pressure= pressure glomerulus- oncotic glomerulus - hydrostatic bowman
what is the GFR?
how to calculate GFR
Glomerulus filtration rate-meaning the amount of filtrate passing from the glomerulus to the bowman capsule per unit time
GFR= pressure net ultra-filtration x constant Kf
affected by surface area and membrane permeability
values of GFR for healthy male and female
90-140 mL/min in males and 80-125mL/min in females
causes of a fall in GFR
renal disease with build up of excretory products
how is the GFR regulated
myogenic mechanism- increase vessel resistance in response to increase BP in arteriole and tubule-glomerular feedback mechanism- decrease ATP and adenosine discharged in response to macula densa
what’s renal clearance? and how to calculate it
amount of plasma that is completely cleared of a particular substance per unit time
conc. in urine x urine flowrate over conc. in plasma
what does freely filtered means?
same concentration of substance passing through the blood and the bowman capsule as filtration process
how to calculate GFR for freely filtered molecule
measuring the renal clearance of the melecule
what molecule used for free filtration
which one is most commonly used
inulin and creatinine
creatinine is most commonly used as the inulin is not found in mammals and therefore should be infused, meaning it is short-lived
what assumption is made when using creatinine?
muscle mass is unchanged and therefore secretion is constant
the amount of creatinine secreted into the PCT is negligible
what is indicated by low renal clearance of creatinine or high plasma creatinine
renal failure
why is creatinine not a perfect molecule
small amount secreted into the nephron
what happens if total amount of a substance entering the kidney equals amount excreted
renal clearance is equal to the RPF
explain the secretion and reabsorption in the renal tubule
draw diagram
explain how creatinine works for GFR determination
amount renal clearance since the creatinine is freely filtered, having the same concentration as the plasma
how to determine renal plasma flow
amount of plasma going into the kidney
total amount entering kidney equals excretion, then renal clearance is equal to RPF, using PAH
how does PAH works?
PAH is completely removed from the plasma by filtration and secretion
what is filtration fraction? How to interpret the results and the formula
ratio of the GFR to the RPF, aka amount filtered from the plasma that ends up in the bowman capsule
transport mechanism in renal tubules for passive and active transport
passive- diffusion, osmoses and electrical gradient
active- primary and secondary
primary active-active transport through pumps or endocytosis
secondary active- solute movement along electrochemical gradient move other solute along
symport and antiport
transport pathways
transcellular and paracellular
what happens in the PCT
reabsorption of Na+ and HCO3- using carbonic anhydrase
angiotensin II effect on Na+-H+ antiport number
glucose symport reabsorption
NaCl and water-67%
glucose-100%
urea 50%
describe the reabsorption in the loop of Henle
15% in descending loop and 25% NaCl in ascending
describe the reabsorption in the DCT
NaCl reabsorption and active Ca2+ reabsorption
describe the reabsorption in the DCT and collecting duct
principal cells and intercalated cells functions
participating pressures in glomerular filtration
blood- hydrostatic and oncotic
interstitial fluid- hydrostatic and oncotic
principal cells control
Na+ and K+ reabsorption in response to aldosterone and ADH
aldosterone-regulation of Na+ reabsorption through apical Na+ channel and basolateral Na+-K+ ATPase pumps
ADH- increase apical aquaporins to control water reabsorption
intercalated cells
maintain acid base balance
alpha-intercalated cells-HCO3- reabsorption and H+ secretion
Beta intercalated cells- HCO- secretion and H+ reabsorption
