Question

Based on your knowledge of sympathetic modulation of heart function explain why beta blockers may be effective in combating hypertension (4 pts):

Answer 1

Sympathetic system have a positive response on the function of heart.

sympathetic system increases the Heart rate , force of contraction ,electrical conduction of the heart.

Sympathetic system supply the heart through the sympathetic plexus coming from the sympathetic trunk.

These nerve endings releases epinephrine neurotransmitter into the heart muscle .

Beta receptors present on the surface of the heart muscle get activated by this neurotransmitter. it result in the conversion of ATP to cyclic AMP with the help of the adenylyl cyclase enzyme. This cAMP will increases the release of calcium from the sarcoplasmic reticulum . THis calcium ion increases the contraction of the heart.thereby the Heart rate is increased.

When we use beta blockers(beta receptor antagonist) it blocks the beta receptor present on the Heart.So, that the sympatheticsupply cannot increase the heart rate and cardiac output.

So, that the Heart rate and cardiac out put are reduced , it will reduce the blood pressure.

So, the beta blockers are effective drug for the treatment of hypertension

Eg of beta blockers are metaprolol, atenolol, carvidolol etc...