This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glomerular Filtration, Renal Blood Flow, and Their Control, Subject name: Physiology
[{'content': 'Most prominent action of angiotensin II- \nSelect and explain. \nA. Vasoconstriction, B. Induction of thirst, C. Increased secretion of aldosterone, D. Increased Na+ reabsorption', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Vasoconstriction o All the given options are caused by angiotensin II. But vasoconstriction is the most prominent action.Actions of angiotensin 11 (A-II)o The most prominent action of A-II is vasoconstriction.o Angiotensin II is one of the most potent vasoconstrictors known, being four to eight times as active as epinephrine.o Vasoconstriction involves arterioles and venules and occurs in all vascular beds. However, it is less marked in cerebral, skeletal muscle, pulmonary and coronary vessels.o A-II increases the force of myocardial contraction by promoting Ca+2 influx.o A-II and A-II I are tropic to zona glomerulosa of adrenal cortex -| aldosterone secretion - Na+ & water retention.o A-II also has a direct action on kidney - promotes Na+, C1- and HCO2- reabsorption.o In brain, A II induces drinking behavior and ADH release. It also increases central sympathetic outflow.o A-II enhances sympethetic activity by peripheral action as well - It releases Adr from adrenal medulla, stimulates autonomic ganglia and increases the output of NA from adrenergic nerve endings.", 'role': 'assistant'}]