unit 3 urinary system Flashcards
function of kidneys
regulation of extracellular fluid
what do the kidneys regulate?
- blood volume
- electrolytes and ions
- pH
- waste products
- hormones, EPO
- vitamin D
what is the urine flow?
- kidneys
- ureters
- bladder
- urethra
renal ptosis
kidneys drop in body
loss of fatty tissue that hold in place
nephron
responsible for forming urine
what are the tubular pats of the nephron?
1,glomerular capsule- filtration
- proximal convoluted tubule- cuboidal, microvilli; reabsorption
- descending loop of Henle
- ascending loop og henle
- distal convoluted tubule- secretion
- collecting duct
glomerulus
mass capillaries in capsule that give rise to filtrate
afferent arteriole
supplies blood to glomerulus
bid in diameter
efferent arteriole
delivers blood to capillaries
small diameter
glomerular capsule
cup shaped, hallow around glomerulus
- parietal layer- sse
- visceral layer- on glom.
- podocytes; feet
filtrate must pass through?
- capillary fenstrate
- glomerular basement membrane
- visceral layer with podocytes
what are the two types of nephrons?
- cortical nephrons- 85%, outer part
2. juxrameduallry nephrons- have long LH, concentrate urine
juxtaglomerular complex
regulating filtrate formation and blood pressure
- ascending limb
- afferent and efferent
what are the three cell populations in juxtaglomerular complex?
- macula densa- asc. limb, Na+
- granular cells- message from macula, afferent, renin
- extraglomerular mesagila cells- connect first 2
what is apart of urine formation and blood regulation?
- glomerular filtration
- tubular reabsorption
- tubular secretion
glomerular filtration rate
volume of filtrate produced by both kidneys each minute
glomerular filtration rate regulation
- vasocontriction/ dilation of afferent arteriole
1. intrinsic regulation- renal auto regulation
2. extrinsic regulation- SNS
intrinsic controls of glomerular filtration
- renal autoregulation
1. myogenic mechanism- smooth muscle, BP
2. tubuloglomerular feedback mechanism- ATP
extrinsic controls of glomerular filtration
- BP
1. neural- SNS
2. Hormonal- renin angiotensin aldosterone
net filtration pressure equation
(HP glom + OPcapsule) - (HPcapsule + OPglom)
glomerular filtration rate is directly proportional to?
- net filtration pressure
- total surface area
- membrane permeability
obligatory water loss
-min of 400 ml/ day is necessary to excrete waste
reabsorption
- return of filtered molecules
- water not actively transported
- active and passive tubular reabsorption
what are the substances that follow the two routes of reabsorption?
- transcellular- across membrane
2. paracellular- next to, around
where does 85% of the reabsorption occur?
- proximal tubules
- descending loop of Henle
sodium transport across the basolateral membrane
- Na+ is most abundant
- active transport
- Na is pumped into interstitial space
- Na is swept into peritubular capillaries
transport across apical membrane
- Na enters cell at apical surface
- secondary active transport
- Na pumped into basolateral membrane
transport maximum
- carriers for a solute are saturated, have glucose bound to is
- want more glucose for more water and urine
countercurrent multiplier
- filtrate flow in ascending and descending limbs of juztamedullary nephrons
- difference in concentration between asc. and dec.
countercurrent exchanger
- blood flow in limbs of vasa recta
- pressure by removing salt and water
osmolality of cortex and plasma
300 mOsm
descending limb
- permeable to H2O
- impermeable to NaCL
ascending limb
- impermeable to H2O
- permeable to salt
- interstitial
collecting duct
- water conservation
- ANP; inhibit Na
what are the different diuretics?
- ADH inhibitors- alc.
- caffeine
- loop diuretics
- osmotic diuretics
renin angiotensin aldosterone system
- decrease in BP and /or blood flow to kidneys
- leads to release of renin
- renin converts to angiotensinogen to angiotensin 1
- then converted to angiotensin 2 by ACE
what does angiotensin Ii stimulate?
- ADH release
- increase thirst
- vasoconstriction
- aldosterone
renal plasma clearance
- filtration in glomerular capsule begins
- secretion finishes process
- moved to peritubular capillaries
excretion rate
C(clearance rate) = U(concentrate) x V(flow) / P(plasma)
inulin
-great marker of glomerular filtration rate
creatinin
-urine creatinin vs blood creatinin