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