Which hormone increase the blood pressure by constricting arterioles during severe hemorrhage?

RRB Nsg. Superintendent 21 July 2019 (shift 1st)

Applied Physiology

Easy

Appeared in: RRB Nsg. Superintendent 21 July 2019 (shift 1st)

Explanation

Anti-diuretic hormone (ADH), also known as vasopressin, is released from the posterior pituitary gland in response to severe blood loss (hypovolemia) and hypotension.
In high concentrations, as seen during hemorrhage, ADH acts as a powerful vasoconstrictor.
It binds to V1a receptors on the smooth muscle of arterioles, causing them to constrict.
This widespread vasoconstriction increases total peripheral resistance, which in turn elevates blood pressure to help maintain perfusion to vital organs.

Option A: Follicular stimulating hormone (FSH) is a gonadotropin involved in the reproductive system. It stimulates the growth of ovarian follicles in females and spermatogenesis in males. It has no direct role in blood pressure regulation.
Option B: Oxytocin's primary roles are stimulating uterine contractions during childbirth and milk ejection during lactation. It does not cause vasoconstriction; it can cause vasodilation and a temporary decrease in blood pressure.
Option D: Luteinizing hormone (LH) is another gonadotropin. It triggers ovulation and corpus luteum development in females and stimulates testosterone production in males. It is not involved in the acute control of blood pressure.

Visual 1: Diagram: The Hypothalamic-Posterior Pituitary Axis. This visual would show the synthesis of ADH in the hypothalamus and its release from the posterior pituitary into the bloodstream.
Visual 2: Flowchart: Physiological Response to Hemorrhage. This would illustrate the sequence of events starting from blood loss, detection by baroreceptors, leading to ADH release, vasoconstriction, and the subsequent increase in blood pressure.

Clinical Relevance

Nursing practice connection: Knowing Hormonal regulation of blood pressure during hemorrhage helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
In clinical practice, synthetic vasopressin is used as a vasopressor agent in the management of refractory shock states, such as septic shock or postcardiac arrest, to increase blood pressure when other agents are insufficient.
Nurses must closely monitor vital signs (blood pressure, heart rate) and urine output in patients at risk for hemorrhage to detect signs of hypovolemic shock early.
Understanding this hormonal response is crucial for anticipating physiological changes and interpreting the rationale for administering vasopressor medications.

How to Approach the Question

First, break down the question: it asks for a hormone that specifically (1) increases blood pressure, (2) by constricting arterioles, (3) during a specific condition, severe hemorrhage.
Next, evaluate each option based on its primary physiological function.
Recall that Follicular Stimulating Hormone (FSH) and Luteinizing Hormone (LH) are gonadotropins, primarily involved in reproduction. This makes them unlikely candidates for acute blood pressure control. Eliminate these options.
Consider Oxytocin. Its main roles are in childbirth and lactation. It is not known for causing vasoconstriction. Eliminate this option.
Finally, analyze Anti-diuretic hormone (ADH). Recall its dual name, vasopressin ('vaso' for vessel, 'pressin' for pressure). This name itself suggests a role in blood pressure. Remember that while its main day-to-day function is water retention, its potent vasoconstrictor effect is activated during emergencies like severe hemorrhage. This perfectly matches all conditions in the question.

Concept Tested & Keywords

Concept Tested: Hormonal regulation of blood pressure during hemorrhage
Stem keywords: hormone, increase blood pressure, constricting arterioles, severe hemorrhage
Lead-in keywords: Which
Clinical cues: The phrase 'severe hemorrhage' is a critical cue, as it points to a state of hypovolemic shock where the body employs potent, emergency mechanisms to raise blood pressure. This context makes the vasoconstrictor role of ADH (vasopressin) the most relevant function.

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