KnowledgeBoat Logo
OPEN IN APP

Chapter 6

Nervous System

Class 7 - Concise Biology Selina


Multiple Choice Questions

Question 1

Medulla oblongata controls:

  1. Smelling
  2. Beating of heart and respiratory movement
  3. Intelligence and will power
  4. Balancing of the Body

Answer

Beating of heart and respiratory movement

Reason — Involuntary functions of internal organs are controlled by Medulla oblongata.

Question 2

Spinal cord is an extension of:

  1. Cerebellum
  2. Cerebrum
  3. Vertebral column
  4. Medulla oblongata

Answer

Medulla oblongata

Reason — Medulla oblongata extends to form spinal cord that runs down to whole length of backbone.

Question 3

Body posture is maintained by:

  1. Cerebrum
  2. Cerebellum
  3. Medulla oblongata
  4. Spinal cord

Answer

Cerebellum

Reason — The function of cerebellum includes coordination of muscular activities and balancing of the body.

Short Answer Questions

Question 1

Write one word in the space provided to complete the second pair of the related words pertaining to nervous system:

Memory : cerebrum :: breathing : ...............

Balance : cerebellum :: reasoning : ...............

Answer

Memory : cerebrum :: breathing : medulla oblongata

Balance : cerebellum :: reasoning : cerebrum

Question 2(a)

Name the two major divisions of the human nervous system.

Answer

The two major divisions of the human nervous system are:

  1. The central nervous system
  2. The peripheral nervous system

Question 2(b)

Name the three main parts of the human brain.

Answer

The three main parts of the human brain are:

  1. Cerebrum
  2. Cerebellum
  3. Medulla oblongata

Question 3

Given alongside is the diagram of a neuron. Name the parts numbered 1-5.

Draw a diagram of human excretory system and label the following parts: Kidney, ureter, urinary bladder and urethra. Excretion in Humans, Concise Biology Solutions ICSE Class 7.

Answer

  1. Dendrite
  2. Nucleus
  3. Cyton
  4. Axon
  5. Terminal Branches

Long Answer Questions

Question 1

With the help of a suitable diagram describe the structure of a neuron.

Answer

A neuron is made up of two main parts —

  1. A main cell body called cyton, which gives out a number of fine processes (dendrites)
  2. A long process called axon.

The cell body contains a nucleus. The dendrites are cytoplasmic extensions of the cell body. They receive messages from the organs and transmit them through the cell body into the axon, which transmits the message. The end of the axon terminates in a number of branches called terminal branches.

Below diagram shows the structure of a neuron:

With the help of a suitable diagram describe the structure of a neuron. Nervous System, Concise Biology Solutions ICSE Class 7.

Question 2

Briefly describe the structure of the cerebrum in human brain and mention its functions.

Answer

Cerebrum is the largest portion of the brain. It is divided into two halves called the right and left cerebral hemispheres. Each hemisphere is internally hollow. The outer surface of the hemispheres is folded with ridges and grooves which increase the surface of the brain so as to accommodate a large number of neurons.

The cerebrum has following functions:

  1. Intelligence
  2. Consciousness
  3. Will power
  4. Memory

Question 3

Mention the three functions of spinal cord.

Answer

The three functions of spinal cord are:

  1. To control reflexes below the neck.
  2. To conduct messages from the skin and muscles to the brain.
  3. To conduct commands from the brain to muscles of the trunk and limbs

Question 4

Describe three kinds of nerves, giving example of each.

Answer

Three kinds of nerves are:

  1. Sensory nerve — It contains only sensory neurons. Example - optic nerve.
  2. Motor nerve — It contains only motor neurons. Example - nerves of the muscles of eyeball.
  3. Mixed nerve — It is the one which carries both sensory and motor neurons. Example - The nerve which goes to the tongue.

Question 5

What are voluntary and involuntary actions? Which part of the nervous system controls them?

Answer

Voluntary actions — The actions or movements that are under the control of one's own will are called voluntary actions. For example, walking, jumping, lifting books, etc. Voluntary actions are controlled by Somatic nervous system.

Involuntary actions — The actions or movements that happen without consciousness or willingness of an individual are called the involuntary action. For example, beating of heart, breathing, digestion, etc. Involuntary actions are controlled by Autonomic nervous system.

PrevNext