Chemical Regulation Of Cvs

CHEMICAL REGULATION OF CVS

Q. 1

EDRF is

 A

NO2

 B

NO

 C

N2O

 D

SO2

Q. 1

EDRF is

 A

NO2

 B

NO

 C

N2O

 D

SO2

Ans. B

Explanation:

Nitric oxide, also called endothelium-derived-relaxing factor (EDRF).

Formed from amino acid arginine, by the action of the enzyme NO synthase, which is cytosolic.


Q. 2

NO is synthesized by

 A

Uracil

 B

Aspartate

 C

Guanosine

 D

Arginine

Q. 2

NO is synthesized by

 A

Uracil

 B

Aspartate

 C

Guanosine

 D

Arginine

Ans. D

Explanation:

Arginine

NO is formed from amino acid arginine.

Nitric oxide, also called endothelium-derived-relaxing factor (EDRF), is formed from amino acid arginine, by the action
of the enzyme NO synthase, which is cytosolic.


Q. 3

The primary action of Nitric oxide (No) in the gastrointestinal tract is

 A

Vasodilatation

 B

Vasoconstriction

 C

Gastrointestinal smooth muscle relaxation

 D

Gastrointestinal slow smooth muscle contraction

Q. 3

The primary action of Nitric oxide (No) in the gastrointestinal tract is

 A

Vasodilatation

 B

Vasoconstriction

 C

Gastrointestinal smooth muscle relaxation

 D

Gastrointestinal slow smooth muscle contraction

Ans. C

Explanation:

Gastrointestinal smooth muscle relaxation

“Nitric oxide (NO) seems to be involved as the neurotransmitter in nonadrenergic noncholinergic (NANC) smooth muscle relaxation throughout the gastrointestinal tract”.



Q. 4

True regarding endothelin-l are all except

 A

Bronchodilation

 B

Vasoconstriction

 C

Decreased GFR

 D

Has inotropic effect

Q. 4

True regarding endothelin-l are all except

 A

Bronchodilation

 B

Vasoconstriction

 C

Decreased GFR

 D

Has inotropic effect

Ans. A

Explanation:

Bronchodilatation 

  • ET, is primarily a paracrine regulator.
  • It causes vasoconstriction, Bronchoconstriction, cardiac stimulation (ionotropic action), a release of aldosterone and ANP, and a decrease in GFR due to contraction of mesangial cells of the kidney.
  • [Ref: Ganong 25th/e p. 595, 24th/e p. 597; Principles of medical physiology p. 265]

Q. 5

All are true about nitric oxide except

 A

Acts through cAMP

 B

Helps to regulate vascular tone

 C

Important role in penile erection

 D

Present in low concentration in cigarette smokers

Q. 5

All are true about nitric oxide except

 A

Acts through cAMP

 B

Helps to regulate vascular tone

 C

Important role in penile erection

 D

Present in low concentration in cigarette smokers

Ans. A

Explanation:

Acts through cAMP.

  • Nitric oxide, acts by stimulating the production of cyclic GMP.
  • In the vasculature, basal release of NO produced by endothelial cells is a primary determinant of resting vascular tone.
  • NO has an important role in producing the penile erection by causing vasodilation and hence engorgement of corpora cavernosa.
  • Cigarette smoking decreases endogenous NO formation and hence increases the risk of cardiovascular disease throughincreased hypertension and platelet aggregation.

Q. 6

Which of the following causes decrease in BP

 A

Thromboxane A2

 B

Vasopressin

 C

NO

 D

PGF2

Q. 6

Which of the following causes decrease in BP

 A

Thromboxane A2

 B

Vasopressin

 C

NO

 D

PGF2

Ans. C

Explanation:

NO

  • Substances which cause vasodilatation can cause fall in BP.
  • Substances which cause vasoconstriction can cause a rise in BP.
  • Among the given options only NO (nitric acid) is vasodilator (causes fall in BP). Other three options cause vasoconstriction (cause rise in BP).


Leave a Reply

%d bloggers like this:
Malcare WordPress Security