Human Brain: Structure and Functions
Class 10 Science | Chapter 7 – Control and Coordination (NCERT/RBSE)
Table of Contents
Definition: The Brain is the central information processing organ of our body. It receives information, integrates it, and sends instructions to effectors (muscles and glands). It constitutes the Central Nervous System (CNS) along with the Spinal Cord.
1. Protection of the Brain
The brain is delicate and requires high-level protection:
- Cranium (Skull): A hard bony box that protects the brain from external mechanical injury.
- Meninges: Three layers of fluid-filled membranes inside the skull.
- Cerebrospinal Fluid (CSF): The fluid present between the meninges. It acts as a shock absorber.
2. Structure and Parts of the Brain
The human brain is broadly divided into three major regions: Forebrain, Midbrain, and Hindbrain.
Fig 1: Lateral View of Human Brain (Schematic).
A. Forebrain
It is the largest and main thinking part of the brain. It consists mainly of the Cerebrum.
- Function: It has specialized areas for hearing, smell, sight, and mental activities like thinking, learning, memory, and emotions.
- Voluntary Actions: It controls the movement of voluntary muscles (e.g., leg muscles).
- Sensation: It has areas associated with hunger (feeling full).
B. Midbrain and Hindbrain
Midbrain: It connects the forebrain to the hindbrain. It controls involuntary actions such as the change in pupil size and reflex movements of the head and neck.
Hindbrain: It consists of three parts:
| Part | Function |
|---|---|
| Pons | Regulates respiration. |
| Medulla oblongata | Controls involuntary actions like blood pressure, salivation, and vomiting. |
| Cerebellum | Controls posture and balance of the body and precision of voluntary movements (e.g., riding a bicycle, walking in a straight line). |
⚡ Previous Year Exam Focus:
- Cerebellum vs Cerebrum: Be clear that Cerebrum is for "Thinking" and Cerebellum is for "Balance".
- Medulla oblongata: Questions often ask which part controls vomiting and BP.
- Diagram: Practice labeling 'Cerebrum' and 'Medulla oblongata'.
Points to Remember
- Thinking Part: Forebrain (Cerebrum).
- Precision/Balance: Cerebellum (Hindbrain).
- Involuntary Actions: Medulla oblongata (Hindbrain).
- Protection: Cranium and CSF.
5. Chapter Assessment
A. Very Short Answer Type Questions (1 Mark)
- Q1. Which part of the brain is the main thinking part?
Ans: Forebrain (Cerebrum). - Q2. What protects the brain from mechanical shocks?
Ans: Cerebrospinal Fluid (CSF). - Q3. Which part of the brain maintains the posture and balance of the body?
Ans: Cerebellum. - Q4. Name the bony box in which the human brain is located.
Ans: Cranium (Skull). - Q5. Which part of the brain controls blood pressure and vomiting?
Ans: Medulla oblongata. - Q6. Which part of the brain controls involuntary actions like pupil size?
Ans: Midbrain. - Q7. Where is the Medulla oblongata located?
Ans: In the Hindbrain. - Q8. How is the brain protected?
Ans: By the Skull (Cranium) and Meninges filled with CSF.
B. Short Answer Type Questions (2-3 Marks)
Q9. Differentiate between Cerebrum and Cerebellum.
| Cerebrum | Cerebellum |
|---|---|
| Part of Forebrain. | Part of Hindbrain. |
| Controls thinking, memory, and voluntary actions. | Controls posture, balance, and precision of movements. |
Q10. A person is unable to walk in a straight line after consuming alcohol. Which part of the brain is affected?
The Cerebellum is affected. Alcohol affects the cerebellum's ability to coordinate muscle movements, leading to loss of balance and improper posture.
Q11. Explain the function of the Forebrain.
The forebrain is the main thinking part. It receives sensory impulses from various receptors. It has separate areas for association where sensory information is interpreted by putting it together with information from other receptors and stored memory. It also controls voluntary muscles.
C. High Order Thinking Skills (HOTS)
Q12. Why is the brain well-protected? Explain the mechanism.
The brain is the control center of the body and is very delicate. To prevent injury, it is housed inside a hard bony box called the Cranium. Inside the box, the brain is covered by membranes (meninges) with Cerebrospinal Fluid (CSF) which acts as a shock absorber.
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