ICSE Class 7 Biology Question 2 of 5

Nervous System in Humans — Question 3

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Question 3

Describe the central nervous system along with its parts and functions.

Answer

The central nervous system consists of the brain and the spinal cord. It is the control centre for all body functions. It is the site for all information processing in the body. It is responsible for processing every sensation and thought a human being experiences. It has two parts — Brain and Spinal Cord.

  1. Brain — The Brain is the main control centre of the nervous system situated in the cranium of the skull. It controls our thinking, feelings, movement and senses. It has three parts — Cerebrum, Cerebellum and Medulla oblongata.
    1. Cerebrum — The cerebrum is the uppermost, largest and the most prominent part of the brain. It is responsible for the sensation of pain, temperature, touch, sight, sound, taste and smell. It also controls mental activities such as memory, intelligence, thinking and reasoning.
    2. Cerebellum — The cerebellum is a small, egg-shaped lobe located at the base under the cerebrum. It helps in the muscle coordination and balance of the body.
    3. Medulla oblongata — The Medulla oblongata is the lowermost part of the brain located at the base of the skull. It controls breathing, heartbeat, coughing, sneezing and other involuntary functions.
  2. Spinal cord — The spinal cord is the continuation of the medulla oblongata of the brain. It is like a cord that emerges from a hole at the base of the skull and runs through the vertebral column. The spinal cord conducts reflexes below the neck. It conducts sensory impulses from the skin and muscles to the brain. It conducts motor responses from the brain to the muscles of the trunk and limbs.

Chapter 8: Human Body: Nervous System — ICSE Class VII Biology Notes

Comprehensive ICSE Class VII Biology notes on the Human Nervous System covering brain parts (cerebrum, cerebellum, medulla), spinal cord, neuron structure, reflex action, reflex arc, and voluntary vs involuntary actions.

Key Concepts and Topics

Topics covered: Brain, Spinal cord, Neurons, Reflex action, Reflex arc

Weightage: Approximately 8 marks in the exam

Important Points to Remember

  • CNS = brain + spinal cord; PNS = nerves
  • Brain parts: cerebrum (thinking), cerebellum (balance), medulla (involuntary)
  • Neuron: cell body + dendrites (receive) + axon (transmit)
  • Reflex action: automatic response controlled by spinal cord
  • Reflex arc: receptor to sensory nerve to spinal cord to motor nerve to effector
  • Brain protected by skull, meninges, and cerebrospinal fluid
  • Voluntary actions involve brain; reflex actions bypass brain

Frequently Asked Questions

Q: What is a reflex action?

A: A quick, automatic, involuntary response to a stimulus, controlled by the spinal cord without involving the brain.

Q: What are the three main parts of the brain?

A: Cerebrum (thinking), Cerebellum (balance), and Medulla oblongata (involuntary actions).

Q: What is a reflex arc?

A: The pathway of a reflex: Receptor → Sensory nerve → Spinal cord → Motor nerve → Effector.

Exam Preparation Tips

  • Focus on understanding concepts rather than rote memorization
  • Practice drawing and labelling diagrams regularly
  • Use comparison tables for topics that require differentiation
  • Solve previous year questions and practice papers
  • Review the chapter notes provided by Bright Tutorials for comprehensive coverage

For complete chapter notes, practice questions, and test papers, contact Bright Tutorials at 9403781999.