Q.2
GFR is determined by the following
A. Bowman capsule pressure
B. Hydrostatic pressure
C. Plasma oncotic pressure
D. All of the above
Explanation :
Increase in glomerular hydrostatic pressure increases the filtration, whereas a decrease in glomerular osmotic pressure or increase in Bowman's capsule hydrostatic pressure decreases the filtration.
Similarly, when afferent arterioles constrict, there is less flow to the glomerulus and less glomerular hydrostatic pressure, consequently less filtration. Whereas, when efferent arterioles constrict, there is increased hydrostatic pressure in the glomerulus resulting in increased filtration.
Q.3
GFR increases if
a) Efferent arteriole constricts
b) Efferent arteriole dilates
c) Afferent arteriole constricts
d) Afferent arteriole dilates
A. AD
B. ABC
C. BC
D. CD
Explanation :
Increase in glomerular hydrostatic pressure increases the filtration, whereas decrease in glomerular osmotic pressure or increase in bowman’s capsule hydrostatic pressure decreases the filtration.
Similarly, when afferent arterioles constrict, there is less flow to the glomerulus and less glomerular hydrostatic pressure, consequently less filtration. Whereas, when efferent arterioles constrict, there is increased hydrostatic pressure in the glomerulus resulting in increased filtration.
Q.4
The best test for GFR is with
A. Inulin
B. Hippuric acid
C. Creatinine
D. PAH
Explanation :
Properties of Inulin
- Easily filtered by kidney
- Not absorbed by kidney
- Not secreted by kidney
- Not metabolized by kidney
- Not synthesized by kidney
- Non-toxic
- Easily measurable
Thus it is the best substance to use for measurement of GFR.
Q.7
Bicarbonate is absorbed
A. Actively in PCT
B. Actively in DCT
C. Indirectly in PCT
D. Actively in DCT
Explanation :
Filtered HCO3- reacts with the H+ which is secreted to the tubule to form H2CO3. This dissociates into CO2 and H2O. CO2can easily diffuse into the epithelial cells and regenerate HCO3-, which is then reabsorbed.
Substances reabsorbed at Proximal tubule
- Na+- 60-70%
- Cl-- 60-70%
- HCO3-- 80-90%
- K+- 60-70%
- Glucose- 100%
- Amino acids- 100%
- Urea- 40-50%
- Water- 60-70%
Q.8
100 % Filtration Coefficient is seen in?
A. Urea
B. Albumin
C. Creatinin
D. Inulin
Explanation :
FILTRATION COEFFICIENT:
Filtration coefficient is a measure of a membrane's permeability to water, taking into account both hydraulic and osmotic pressures.
(Note: Filtration coefficient 100= Filterability
1) Filterability of Solutes Is Inversely Related to Their Size. The glomerular capillary membrane is thicker than most other capillaries,
but it is also much more porous and therefore filters fluid at a high rate. Despite the high filtration rate,
the glomerular filtration barrier is selective in determining which molecules will filter, based on their size and electrical charge.
A filterability of 1.0 as in the case of inulin means that the substance is filtered as freely as water Inulin Clearance Can Be Used to Estimate GFR:
If a substance is freely filtered (filtered as freely as water) and is not reabsorbed or secreted by the renal tubules,
then the rate at which that substance is excreted in the urine is equal to the filtration rate of the substance by the kidneys.
Q.13
Erythropoietin level are increased by -
1) ↓PO2
2) ↓PCO2
3) ↓Hb
4) ↓pH
A. A
B. AB
C. ABC
D. BC
Explanation :
Hypoxia stimulates the release of Erythropoietin.
Q.16
The main site of bicarbonate reabsorption is
A. Proximal convoluted tubule
B. Distal convoluted tubule
C. Cortical collecting duct
D. Medullary collecting duct
Explanation :
Substances reabsorbed at Proximal tubule
- Na+- 60-70%
- Cl-- 60-70%
- HCO3-- 80-90%
- K+- 60-70%
- Glucose- 100%
- Amino acids- 100%
- Urea- 40-50%
- Water- 60-70%
Q.17
The Principal site of absorption of sodium is
A. Proximal convoluted tubule
B. Distal convoluted tubule
C. Loop of Henle (thick portion)
D. Collecting duct
Explanation :
Other than at thin descending limb of the loop of Henle, all other sites of tubule Na+ are reabsorbed by various mechanisms.
- Proximal tubule- 60-70%
o Na+-H+ exchange
o Na+- Glucose co-transport
o Na+- amino acid co-transport
o Na+ unitransport
- The thick ascending limb of the loop of Henle- 30%
o Na+-2Cl--K+ co-transport
- Early distal tubule- 7%
o Na+-Cl- co-transport
- Late distal tubule and collecting duct- 3%
o ENaC channels
Q.19
Relaxation of mesangial cells of the kidney is brought about by
A. cAMP
B. Endothelin
C. PGF2
D. Vasopressin
Explanation :
Substances causing relaxation of mesangial cells
- ANP
- Dopamine
- PGE2
- cAMP
Substances causing contraction of mesangial cells
- Endothelin
- Vasopressin
- PGF2
- Angiotensin II
- Norepinephrine
- PAF
- PDGF
- Thromboxane A2
- Leukotrienes C4, D4
- Histamine
Q.20
In proximal convoluted tubule H* is exchanged for?
A. Na +
B. K +
C. HCO3 --
D. Cl --
Explanation :
Sodium-hydrogen counter-transport occurs in several tissues. An especially important example is in the proximal tubules of the kidneys, where sodium ions move from the lumen of the tubule to the interior of the tubular cell, while hydrogen ions are counter transported into the tubule lumen
