And All Correct Answers Graded A+.
Kidneys receive ___ cardiac output - Answer 15~30%
Blood flow to renal bed = ____ greater than to most other organs - Answer 10~50×
Renal Functions: - Answer 1. Urine formation
2. Elimination of waste products
3. Homeostatic regulation:
> ECF volume and osmolarity (ADH)
> Na+ retention and K+ excretion (aldosterone)
> Ca++ retention and phosphate wasting (PTH, Vitamin D)
> pH balance (excretion or reabsorption of H+ or HCO3- )
4. Regulating hormones and enzymes
Urine formation - Answer - Glomerular filtration
- Tubular reabsorption
- Tubular secretion
- Excretion
Elimination of waste products (nitrogenous + other end products of metabolism) produced
daily: - Answer - Urea - 25~30 g (BUN = 8~28 mg/ml)
- Creatinine - 1~2 g (normal value = 0.5~1.0 mg/ml)
- Uric acid - (normal value = 3.0~5.0 mg/ml)
- Others - (Sulfates, Nitrates, Phosphates, Magnesium)
Filtration: - Answer Blood to lumen
Reabsorption: - Answer Lumen to blood
,Amount filtered - Amount reabsorbed + Amount secreted = - Answer Amount of solute
excreted
Erythropoietin - Answer Endothelial cells of peritubular capillaries secrete erythropoietin in
response to hypoxia for RBC formation --- Anemia of Chronic Renal Failure
Erythropoietin is released from ___ and is stimulated by ___ - Answer Kidneys; stimulated by
low oxygen
Target cells of erythropoietin = - Answer Bone marrow
Response of erythropoietin = - Answer RBC formation
Vitamin D Metabolism - Answer - Conversion of 25-OH vitamin D (storage form) to 1,25-(OH)2
vitamin D (active form) by 1α;-hydroxylase, which is activated by PTH. **
- Controls our calcium
- In our GI tract
Renin - Answer - JG (juxtor glomerular) cells secrete renin in response to ↓ renal arterial
pressure and ↑ renal sympathetic discharge (b1 effect) --- Renin-Angiotensin-Aldosterone
System
- Can increase aldosterone and hypertension
- Uses ACE
Prostaglandins - Answer - Secretion of prostaglandins that vasodilates the afferent arterioles
to increase GFR.
- Should avoid aspirin/NSAID because they decrease prostaglandins and inhibits juxta (?)
5 components we need to know for every hormone: - Answer 1. Released from where
(location)
2. Stimulus (response to what)
3. Targets
4. What type of response(s)
5. Feedback (+ or -; usually is -)
,ADH is released by - Answer Posterior pituitary gland
Vasopressin (ADH) action on kidney - Answer ↑ H2O permeability of principle cells in
collecting duct
↑ urea absorption in collecting duct
↑ Na+/K+/2Cl- transporter in thick ascending limb
Aldosterone stimulus for secretion - Answer ↓ blood volume (via RAA system)
↑ plasma [K+]
↑ Ang II
Aldosterone is released by the - Answer Adrenal cortex
Aldosterone's action on kidney - Answer ↑ Na+ reabsorption
↑ K+ secretion
↑ H+ secretion in distal tubule
Ang II stimulus for secretion - Answer ↓ blood volume (via renin)
Ang II's action on kidney - Answer Contraction of efferent arteriole → ↑ GFR
↑ Na+ and HCO3- reabsorption in proximal tubule
ANP stimulus for secretion - Answer ↑ atrial pressure
ANP is released from the - Answer Cardiac muscle
ANP's action on kidney - Answer ↓ Na+ reabsorption
↑ GFR
, PTH's action on the kidney - Answer ↑ Ca2+ reabsorption
↓ (PO4)3- reabsorption
↑ 1,25-(OH)2 vitamin D (calcitriol) production
Atrial natriuretic peptide (ANP) secreted in response to - Answer ↑ atrial pressure
causes ↑ GFR
↑ Na+ excretion
Aldosterone secreted in response to - Answer ↓ blood volume (via AT II)
and ↑ plasma [K+]
causes ↑ Na+ reabsorption
↑ K+ secretion
↑ H+ secretion
Parathyroid hormone (PTH) secreted in response to - Answer ↓ plasma [Ca2+]
causes ↑ [Ca2+] reabsorption (DCT),
↓ PO43- reabsorption (PCT)
1,25(OH)2 vitamin D production →↑Ca2+ and PO43- reabsorption
Glomerular Filtration = - Answer ~ 180L/day (about 1% is excreted)
2 types of pressure from the capillary - Answer Hydrostatic and Colloidal (aka oncotic)
Capsule pressure seen in GFR - Answer Back pressure and net filtration pressure
GFR is the index of - Answer Renal function (measure this for good filter)
GFR assessed via: - Answer Inulin - fructose polysaccharide - freely filtered, not reabsorbed or
secreted; clinically, inulin clearance (Cin) is the gold standard measure of GFR
Creatinine - endogenous substance freely filtered, not reabsorbed, not secreted except at very
high plasma concentrations