Mechanism triggered by increased salt intake – Physiology MCQ
Most important mechanism which gets triggered in the first few hours after large increase in salt and water intake is?
A. Small increase in arterial pressure
B. Suppression of angiotensin II formation
C. Activation of low pressure receptor reflexes
D. Stimulation of natriuretic systems
Correct answer: C. Activation of low pressure receptor reflexes
- As sodium intake is increased, sodium output initially lags slightly behind the intake.
- This time delay causes small increase in cumulative sodium balance.
- This leads to slight increase in extracellular fluid volume.
- This increase in extracellular fluid volume triggers various mechanisms in the body to increase sodium excretion.
- On intake of large quantities of salt and water, signals from the stretch receptors of the right atrium and the pulmonary blood vessels go to the brain stem.
- This will inhibit sympathetic nerve activity to the kidney.
- This in turn leads to decrease in tubular sodium reabsorption.
- This mechanism is most important in the first few hours after large increase in salt and water intake.
Ref: Textbook of Medical Physiology, Guyton and Hall, 11th edition, page 380.
