Q1. [5] medium exam-ready
(i) Draw a neat labelled diagram of the human brain identifying its three major regions.
(ii) Describe the specific functions of the fore-brain, cerebellum, and medulla oblongata.
(iii) Why is damage to the medulla oblongata considered immediately life-threatening, whereas damage to the cerebellum, though serious, is not?
Generated by claude-sonnet-4-6 · 2026-06-26 01:01 · grounding rag
Model Answer
(i) Diagram of the Human Brain
(Draw and label: Fore-brain (cerebrum), Mid-brain, Hind-brain — showing Cerebellum and Medulla oblongata)
```
[FORE-BRAIN / Cerebrum]
/
[MID-BRAIN]
\
[HIND-BRAIN]
├── Cerebellum
└── Medulla Oblongata
|
Spinal Cord
```
(A neat diagram with the above three regions and parts labelled is expected.)
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(ii) Functions:
- Fore-brain: Main thinking part; receives sensory impulses (hearing, smell, sight); interprets and stores information; controls voluntary muscles; contains centres for hunger and other sensations.
- Cerebellum: Part of hind-brain; responsible for precision of voluntary actions and maintaining posture and balance of the body (e.g., walking straight, riding a bicycle).
- Medulla Oblongata: Controls involuntary actions — blood pressure, salivation, vomiting, heartbeat, and breathing.
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(iii) Medulla oblongata controls vital involuntary functions like heartbeat and breathing. Damage stops these immediately, making it life-threatening. Cerebellum controls balance and coordination of voluntary actions — serious but not immediately fatal, as these functions can partially be managed or compensated over time.
Source: Chapter 6, Section 6.1.2 — Human Brain
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Explanation
- For the diagram, even a simple schematic with correct labels of all three major regions (fore-brain, mid-brain, hind-brain) and key parts (cerebellum, medulla) fetches full marks. Neatness matters.
- Examiners look for specific key terms: "precision of voluntary actions," "posture and balance" for cerebellum; "involuntary actions," "blood pressure, salivation, vomiting" for medulla.
- For part (iii), the logic is simple: medulla = vital functions (heart, breathing) → immediate death if damaged; cerebellum = coordination only → serious but survivable. State this contrast clearly.