Question

The brain stem comprises of :
A. Pons
B. cerebellum
C. mid brain
D. mamillary body
E. medulla oblongata
Choose the correct answer from the options given below :

• A. A, B and E only
• B. B, C and D only
• C. C, A and B only
• D. A, C and E only

Hint:

To remember the brainstem from top to bottom, think M.P.M.: Midbrain, Pons, Medulla. The cerebellum just "hangs on" to the back of the Pons for the ride!

Answer 1

The Correct Option is D

Step 1: Concept:
This question requires strict anatomical identification of the structures that structurally and functionally compose the human brainstem.

Step 2: Step-by-step Explanation:

• The brainstem is the stalk-like lower portion of the brain that physically connects the higher cerebral hemispheres to the spinal cord. It houses critical autonomic control centers (like breathing and heart rate).

• Anatomically, the brainstem is rigidly defined as consisting of exactly three structures, arranged from top to bottom:
1. Midbrain (Mesencephalon) (C) - The uppermost segment.
2. Pons (A) - The bulging middle segment.
3. Medulla oblongata (E) - The lowest segment that continuously merges into the spinal cord.

• Let's review the distractors:
- Cerebellum (B): While it sits right behind the brainstem and connects to the pons via peduncles, it is a separate structural organ responsible for motor coordination, not a part of the brainstem stalk itself.
- Mamillary bodies (D): These are small round structures on the undersurface of the brain involved in memory. They are anatomically part of the diencephalon (limbic system), sitting just above the midbrain.

• Therefore, only A, C, and E belong to the brainstem.

Step 3: Final Answer:
The correct option is (D) containing A, C, and E only.