Renal Physiology Flashcards
Normal pH of Kidneys
7.4 by regulating H+ and HCO3-
Positive Balance
Intake exceeds output
Negative Balance
Output exceeds input
Weight of both kidneys
300 grams of <0.5% body weight
How many nephrons in adult Kidney?
1.2 million… can life active life with only 25% of these
Superficial Nephrons
short loop of Henle
efferent arteriole gives rise to peritubular capillaries
no thin ascending limb
Juxtamedullary Nephrons
long loop of Henle
Thin ascending limb
Efferent arteriole gives rise to peritubular capillaries AND ascending vasa recta
Proximal Tubule
Brush border on apical side, highly invaginated basolateral membrane filled with mitochandria
Straight portion of Proximal Tubule (pars recta)
much less well endowed with basolateral infoldings and mitochandria
Thin descending and thin ascending loop of Henle
poorly developed apical and basolateral membranes and few mitochandria
Thick ascending Limb of Henle and Distal Tubule
Extensive basolateral infoldings with mitochondria
Collecting Duct
Principle cells and Intercalated cells
Principle cells
Moderately invaginated basolateral membrane with few mitochondria.
Important for Na and Cl reabsorption
Intercalated Cells
Have high density of mitochondria
One population secretes H+
The other secretes HCO3-
Renal Blood flow
25% of cardiac output
5L/min and 25%= 1250ml/min-1ml/min=1249ml/min
Urinary Flow Rate (V)
1 ml/min
Renal Plasma Flow
Renal Blood Flow (RBF) x (1-hematocrit)
Water
180L/day filtered
42L in human
Sodium
25,000 mEq/day filtered
3,000 mEq in human
3rd space
Part of ECW including peritonea, synovial, pleural, cerebral spinal fluids, saliva.
Increase in 3rd space with ascites
Plasma
92& water
7% protein
1% small solutes
ECW
ICW
Na, Cl, HCO3-
K, organic phosphate and protein
Volume (equation)
Volume= amount/concentration
Osmolality
The concentration of discrete osmotically active particles in solution
Function of # particles regardless of mass, charge, size
Which has higher osmolality, interstitium or plasma?
Plasma bc of higher protein concentration
Generalized Edema
Both ICFV and ECFV expand
Osmolality falls
Gain of isoosmotic/isotonic NaCl
Add Pure water
Decreased excretion by kidneys of Na and Cl
Severe Diarrhea
Only ECFV expands
No change in osmolality
Loss of isosmotic/isotonic NaCl
Add isotonic NaCl