4.Kidneys Flashcards
Anatomy of the kidney
Afferent arteriole, glomerulus, Efferent arteriole,
Glomerulus Loop of Henle, Peritubular Capillaries, Collecting Duct
4 Steps of GFR?
- Filtration
- Reabsorption
- Secretion
- Excretion
Normal GFR =
• Osmolarity ~
125 ml/ min / 1.73 m2
- Male ~ 7.5 L/h = 180 L/day!
- Female ~ 6 L/H = 144 L/day
300 mosmol/L = ECF
Intrinsic mechanisms which control GFR include?
Tubulo Glomerular Feedback
Extrinsic mechanisms which control GFR include the?
sympathetic nervous system
Step 2: Reabsorption… lots of electrolytes + water
name the 2 steps in this
- The filtrate passes along a tube equipped with aquaporins that are relatively impermeable to urea.
- Salt and water are absorbed from the tube, leaving most of the urea behind with
a small amount of remaining water
Basolateral ATPase
3 Na+ to 2 K+
• Cell: Low Na, high K,
__ mV potential
-70
• Apical facilitated diffusion
– Gradient of Na ?
– Negative potential ______cell
– Gradient Na+ 140 mM vs 12 mM
– Negative potential inside cell
The Na gradient is maintained by
the Na/K ATPase pump
Na+ coupled glucose
symporter:
co-transport
Secondary active reabsorption. How much
- Glucose?
- Na ?
- Glucose~ 5mmol/L
* Na ~ 140 mmol/L
The end of the Proximal Tubule
_____fluid is ↓ from 6 L/h to approximately ~ 1.2 L/h.
i.e. best guess, 80% of ____is reabsorbed
Tubular
GFR
The Na-K ATPase maintains a sodium gradient to enable ?
Na+ reabsorption
what happens to [Na] concentration at the end of the Proximal Tubule?
No change in [Na] concentration