renal Flashcards
functions:
make urine, filters waste out of the body, fluid balance, Ph balance, secondary endocrine: erythropoitein, renin, vit d, reabsorbtion/secretion/excretion
nephron
functional units of the kidneys
filtration begins at the …..
bowmans capsule
descending loop of henle is permeable to ….
h20
the ascending limb of henle is permeable to _____
solutes
ADH
stimulation: osmoreceptors, low Bf/decreased bp/ANG2/atrial stretch receptors/barrorecptors(-stretch)–>+ADH
actions: +expression of aquaporions on the apical side of tubular cells of the DCT
vasa recta
BV that picks up materials reabsorbed at the capillaries, surrounding the medullary loop
DCT
short nephron segment between macula densa/collecting ducts
(absorbs ions and h20)
Loop of henle
site of 20% solute reabsorption, makes the concentration gradient to pull H2O out( descending), and reabsorb solutes (ascending)
what is the toop of the loops concentration?
300mosm/L
concentration of the bottom of the loop?
1200 mosm/L
What is the concentration after the DCT?
-100 mosm/L
PCT?
segment of of renal tubule that absorb/secretes h2o& solutes ( in the renal cortex)
reabsorption mechanisms
transcellular:Na+ gradients/supporting transport proteins
secondary active transport: atp used to transport molecule against gradient and another molecule piggy backs.
paracellular: passive, H2o follows osmotically charged particles
Distal convoluted tubules & collecting ducts:
winds around the bowmans capsule
- dilute, -100mosm/L
ANP
stim: stretch receptors in the atrial myocytes detect the vol of BF, actions= dilates the afferent arterioles do +GFR–>+Na+ filtered= surpresses the release of ALDO -ANG2 & ALDO(decreases H2O reabsorption by DCT promotes more urine, stims vaso D)
RAAS
afferent arteriole sense low p–> renin released, Juxtaglomerular cells in kidneys–>angiotensinogen released from the liver—>converts to ANG1–> ACE–> ANG2–> decreases bv diameter, ec proliferation, +bp
GFR=
vol filtered/unit of total blood
125ml/min=180L/day
myogenic model:
High pressure—> higher BF through the afferent arteriole→ + GFR
+BP= smooth muscle stretch→ opening the VG Ca2+ channels→ Ca2+ allows for the cross bridge to form—> + Smooth muscle contraction of cells
When Pressure decreases, smooth muscles relax, + BF & GFR
Tubuloglomular feedback
+ bf through the afferent arteriole→ + GFRs & + Flow of filtrate through the nephron
+ bf = sensed by the macula densa cells of the JGA
Macula densa cells secrete paracrine factors of adenosine & ATP —> smooth muscle cells of the afferent arteriole to contract —> decreases the GFR→ secrete less NO ( Nitric oxide)
When BF= decreased through the afferent arterioles, macula densa cells secrete less adenosine & ATP and more NO
Permeability of glomerulus= altered by angiotensin 2 (decreases GFR)