renal phys Flashcards
fxns of the kidneys
- Regulation of extracellular fluid volume and blood pressure
- Regulation of osmolarity
- Maintenance of ion balance
- Homeostatic regulation of pH
- Excretion of wastes
- Production of hormones
retroperitoneal cavity
- behind peritoneal cavity
three sections of the kidneys
- renal pelvis (pyramids aligned w/ the nephron), medulla (deep), and cortex (superficial)
what supplies blood to the kidneys?
- the renal artery
- 25% of cardiac output goes to the kidneys
nephron
- filtration unit, contains glomerulus and renal tubules
– Blood filtered by glomerulus –> removal of waste (urea and nitrogen-containing compounds ) and regulation of extracellular electrolytes and intravascular volume
– Produces urine
majority of reabsorption happens where?
- proximal convoluted tubule
bowman’s capsule
- site of plasma filtration with the glomerulus
glomerulus
- first capillary bed, a ball-like network
- goes from afferent arteriole to this
proximal convoluted tubule
- filtered fluid flows from bowman’s capsule to this
loop of henle
- fluid goes from the PCT to this structure
- descending limb: osmolarity decreases
- ascending limb: osmolarity increases
distal convoluted tubule
- fluid goes from the loop of henle to this
collecting ducts
- receives fluid from the DCT
- converge and drain into the renal pelvis
Collecting ducts pass from the ___ through the ____ and drain into the _____
- cortex
- medulla
- renal pelvis
what kind of ions do we want to pass thru
- small ions w/ a pos charge
- ex: Na+ – also most common
what do kidneys do?
- filter
- reabsorb
- secrete
filtration
- getting stuff in the kidneys
– Fluid from blood into the lumen of the nephron (Bowman’s capsule)
– Filtered plasma is called filtrate
reabsorption
- mostly happens in proximal convoluted tubule
– Materials in the filtrate are passed back into the blood
– Peritubular capillaries
secretion
– Active transport from peritubular capillaries
- removes molecules from the blood and adds them to the filtrate in the tubule lumen n
increase in BP and BV increases what? What about decrease in BP and BV
- filtration
filtrate is protein-free plasma
– Endothelial cells of glomerular capillaries –> Bowman’s capsule
▪ Filtration slits in glomerular capillaries
▪ Hydrostatic pressure (capillary blood pressure)
how much water and ions is reabsorbed in the PCT
- about 70%
filtrate in the loop of henle
– More ions (Na+, K+, Mg2+, Ca2+) reabsorbed than water, dilute filtrate in lumen
distal tubule
– Resorption of ions and water, secretion of some substances
– Depending on hydration status
where things go in the nephron
- In bowman’s capsule water, sodium, potassium, glucose, and urea go out of blood into capsule
- PCT - some water, sodium, potassium, all glucose gets reabsorbed
- Loop of henle - descending loop = the rest of the water exits the tubule. Ascending loop = salt exits
- No water in DCT but we reabsorb sodium and chloride
- Collecting duct = receives filtrate from the DCT and delivers urine
what happens in the loop of henle?
- Na+, Cl- enters the artery from the ascending limb of the loop of Henle, so the blood becomes more concentrated, which is bad because then we cannot maintain homeostasis
- So, water from the descending limb of the loop of Henle leaves and enters the artery to maintain the normal blood concentration
- the result is blood that maintains good concentration and urine that adjusts to make sure blood maintains that good concentration
ppl who can’t absorb all their glucose excrete it out. this is a sign of what
- diabetes
aquaporin 1 and 2 are found where?
- 1 = loop of henle
- 2 = found in collecting duct
what needs to be present in order to reabsorb water?
- ADH
what 4 things determine filtration?
- BP
- BV
- Size
- Charge of ion
what do we not want in the kidneys?
- calcium
- kidney stones
- also proteins like albumin
sodium going into the blood is what transport?
- active
what two things hitch a ride with Na+ in the PCT?
- glucose and H2O
aldosterone in the kidneys
- takes out sodium back into the blood (water will follow)
- brings K+ and acid into the kidney
