Which part of the brain controls involuntary actions, including blood pressure, salivation, and vomiting?

Appeared in: RRB Nsg. Superintendent - 29 April 2025 (Shift-3rd)

Explanation

The medulla, part of the hindbrain, contains vital autonomic centers that regulate life-sustaining functions.
Specifically, it houses the vasomotor center, which controls blood pressure.
It also contains reflex centers for salivation (salivatory nuclei) and vomiting.
These functions are involuntary, meaning they occur without conscious thought, which aligns with the question's description.

Option A: The thalamus is primarily a relay station for sensory information going to the cerebrum. It is not involved in the autonomic control of blood pressure or vomiting.
Option B: The cerebrum is responsible for higher-order functions like voluntary movement, thought, and memory, not basic involuntary reflexes.
Option D: While the pons is part of the hindbrain and assists in regulating respiration, it is not the primary center for controlling blood pressure, salivation, and vomiting.

Visual 1: Diagram of the Human Brain - A side-view diagram clearly labeling the forebrain (cerebrum, thalamus) and hindbrain (pons, medulla, cerebellum) to help visualize the locations of the structures mentioned in the options.

Clinical Relevance

Nursing practice connection: Knowing Anatomy and Physiology of the Brain helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Damage to the medulla oblongata, for example from a brainstem stroke or head trauma, can be immediately life-threatening because it disrupts control over breathing, heart rate, and blood pressure.
Nurses closely monitor for signs of brainstem dysfunction in patients with neurological injuries, such as changes in respiratory pattern, unstable blood pressure, and loss of protective reflexes like gagging or coughing.
What if? - If a patient had a lesion specifically in the pons, the nurse might observe altered breathing patterns (like apneustic breathing) and problems with balance and coordination, rather than the immediate loss of vital functions controlled by the medulla.

How to Approach the Question

First, identify the keywords in the question: 'involuntary actions,' 'blood pressure,' 'salivation,' and 'vomiting.'
This is a factual recall question about neuroanatomy and physiology.
Mentally review the major functions of the different brain parts listed in the options.
Recall that the brainstem (hindbrain) controls basic survival functions.
Differentiate between the functions of the medulla, pons, thalamus, and cerebrum.
Match the specific involuntary actions (blood pressure, vomiting) to the correct brain structure, which is the medulla.

Concept Tested & Keywords

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Practise the full RRB Nsg. Superintendent - 29 April 2025 (Shift-3rd)

Attempt every question from this paper in a timed mock, then review the full solution for each one.