- Loss of a large quantity of blood in an individual due to haemorrhage provokes many physiological changes which are compensatory and decompensatory in nature. The following statements describe few compensatory or decompensatory mechanisms operating in this
condition.
A. The peripheral chemoreceptors are stimulated when arterial blood pressure is reduced below 60 mm Hg due to blood loss.
B. The cardiovascular centres in the brain stem become depressed in severe hypotension due to
blood loss.
C. The mononuclear phagocytic system becomes depressed during the course of haemorrhagic
hypotension.
D. Renin is secreted from juxtaglomerular apparatus in haemorrhagic hypotension.
E. Considerable quantity of interstitial fluid may be drawn into circulation due to lower
hydrostatic pressure in capillaries resulting from blood loss.
Choose the option describing only the decompensatory mechanisms:
(1) A and B (2) B and C
(3) C and D (4) D and E
Hemorrhagic shock, caused by acute blood loss, triggers a cascade of physiological responses aimed at restoring blood volume, pressure, and tissue perfusion. Understanding these responses is crucial for effective clinical management and patient recovery.
Assessment of Proposed Statements
A. Decrease in arterial pressure after hemorrhage causes inhibition of sympathetic-vasoconstrictor system
-
Incorrect. The fall in arterial pressure stimulates the sympathetic-vasoconstrictor system, increasing vascular tone and heart rate to maintain blood pressure.
B. After hemorrhage, angiotensin II level in blood increases causing increased Na+ reabsorption in renal tubules
-
Correct. Activation of the renin-angiotensin system leads to angiotensin II production, stimulating sodium retention and vasoconstriction.
C. Increased secretion of vasopressin after hemorrhage increases water retention by kidneys
-
Correct. Vasopressin promotes water reabsorption in collecting ducts, aiding volume restoration and blood pressure maintenance.
D. After hemorrhage, reduced secretion of epinephrine and norepinephrine from adrenal medulla induces decreased peripheral resistance
-
Incorrect. Catecholamine secretion increases after hemorrhage to enhance peripheral vasoconstriction and maintain blood pressure.
E. CNS ischemic response elicits sympathetic inhibition during hemorrhage
-
Incorrect. CNS ischemic response causes sympathetic excitation to preserve cerebral perfusion.
Correct Combination of Statements
Only statements B and C are correct, making option:
(2) B and C
-
