- A person recovered from a moderate degree of haemorrhagic shock. The participating physiological mechanisms in this recovery process are proposed in the following statements.
A. The decrease in arterial pressure after haemorrhage causes inhibition of sympathetic-vasoconstrictor system.
B. After haemorrhage, the angiotensin ll level in blood is increased which causes increased re-absorption of Na+ in renal tubules.
C. The increased secretion of vasopressin after haemorrhage increases water retention by the
kidneys.
D. After haemorrhage, the reduced secretion of epinephrine and nor-epinephrine from adrenal
medulla induces decreased peripheral resistance.
E. In haemorrhage, the central nervous system ischemic response elicits sympathetic inhibition.
Choose one of the following combinations with both the correct statements.
(1) A and B (2) B and C
(3) C and D (4) D and E
Hemorrhagic shock occurs due to substantial blood loss, causing reduced blood volume and decreased arterial pressure. Recovery from moderate hemorrhagic shock involves activation of multiple compensatory physiological mechanisms that work to restore blood volume, pressure, and tissue perfusion.
Evaluation of Proposed Statements
A. Decrease in arterial pressure after hemorrhage causes inhibition of sympathetic-vasoconstrictor system
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Incorrect: The opposite occurs; arterial pressure drop stimulates activation of the sympathetic vasoconstrictor system to increase heart rate and vasoconstriction, raising blood pressure.cvphysiology+1
B. After hemorrhage, angiotensin II levels increase, causing increased Na+ reabsorption in renal tubules
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Correct: Angiotensin II is generated through renin-angiotensin system activation and promotes sodium reabsorption to increase blood volume.ncbi.nlm.nih+1
C. Increased secretion of vasopressin after hemorrhage increases water retention by kidneys
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Correct: Vasopressin (antidiuretic hormone) promotes water reabsorption in collecting ducts, aiding volume restoration.onlinelibrary.wiley+1
D. After hemorrhage, reduced secretion of epinephrine and norepinephrine from adrenal medulla induces decreased peripheral resistance
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Incorrect: Secretion of epinephrine and norepinephrine increases during hemorrhage, increasing peripheral resistance and cardiac output.cvphysiology
E. CNS ischemic response elicits sympathetic inhibition after hemorrhage
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Incorrect: CNS ischemic response leads to intense sympathetic excitation to maintain perfusion of vital organs.cvphysiology
Correct Statements Combination
Among the choices, only option:
(2) B and C
includes both correct mechanisms: increased angiotensin II causing Na+ reabsorption and increased vasopressin secretion causing water retention.
Conclusion
Recovery from hemorrhagic shock is characterized by:
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Sympathetic vasoconstrictor system activation (not inhibition),
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Increased angiotensin II and vasopressin release,
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Elevated catecholamine release,
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Sympathetic excitation by CNS ischemic reflex.
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