export_renal function Flashcards
1
Q
Tubuloglomerula feedback
A
- Macula densa detect inc GFR
- JGC in aff arteriole –> renin
- Mesangial cells help vaso con of aff to reduce GFR
2
Q
Secretion in PCT
A
- always ionised
- non-selective
- active
- basolat secreteion of drugs, must give penicillin with OAT-blocker to see effects longer
3
Q
Urea formation
A
Transamination of aa –> deamination –> free NH4+ –> NH3 in Urea
4
Q
High GFR needed for Urea excretion, why?
A
- Very small therefore l ittle bit lipid-sol
- w/o high GFR lots would diffuse into the blood
- synth in liver as job is to convert lipid sol –> water sol
5
Q
Bicarbonate balance, PCT
A
- lost as a buffer for CO2
- apical memb = imperm; basolat = perm
- intercalated cells w/ lost of c. annhydrase
- carbonic anhydrase –> HCO3- + H+ in epi cells
- HCO3- –> peritub cap.
6
Q
H+ balance
A
- secreted as bicarb ions reabs
* secreted as convert NH4+ –> NH3
7
Q
LoH creation of osmotic gradient
A
- water moves out of desc LoH
- no aquaporins in asc LoH
- Ions actively transported out
- more water out of desc LoH
- concentrating filtrate even more (if dehydrated = good)
- reabsorption only in CT by osmosis and ADH influence
8
Q
ADH control of urine concentration
A
- filtrate concentrated from LoH
- ADH released if dehyrated/low BP
- inserts aquaporins to DCT and Coll duct
- water moves from filtrate into peritubular cap
9
Q
Calcium reabsorption
A
- most in PCT
- facillitated diff by Vit D
- 50% is protein bound therefore NEVER filtered
- PTH stim active reab of Ca++
- Calcitonin inhibs this reabs
10
Q
Na+ Reabs
A
- 80% kidney energy
- most reabs in PCT (NaKPump, symp/antiporters)
- principle cells: NaKpump on basolat, leak on apical
- end of DCT and Col duct reabs finely tuned, sep from water reabs
- aldosterone stim activity and synth of more pumps
11
Q
K+ reabs
A
- ALL reabs,
- most in PCT, diffusion
- paracellular, after water
- secretion vital as more is excreted than filtered!
- aldosterone controlled
12
Q
What animal alters urine composition between the collecting duct and bladder?
A
Horse, glands in renal pelvis and upper ureter secrete mucus
13
Q
Control of urination
A
Internal sphincter = smooth m (invol)
- symp n, lumbar
- contracts, symp a1 receptors
Ext sphincter = skel (vol) - delay dilation by lumbar somatic motor nerves
- continuous stim by nACh to remain closed
Detrusor relaxes - B2 N.A receptors
14
Q
Bladder emptying
A
When full, stretch receptors
Myogenic reflex = either pee or hold
- p-symp
- Ach on muscarinic R
- Detrusor contract; int sphincter relax
- inhibit somatic stim of ext sphincter
15
Q
When would protein in urine not indicate kidney impairment?
A
- Inflam of repro tract or urinary tract
* Sediment analysis would ID
