Exercise 20 the Autonomic Nervous System Review Sheet Answers

ICSE Selina Class viii Biological science Chapter 7 – The Nervous Organisation explains about the system that consists of the brain, the spinal cord, and an enormous network of nerves that are spread throughout the torso which is responsible for sending, receiving and processing the messages in the form of chemical signals, called impulses. ICSE Selina Class eight Biological science Chapter vii – The Nervous System Solutions covers all the questions given in the Selina Publication for class 8. The answers provided by ICSE Selina Class eight Biology Chapter vii – The Nervous Arrangement Solutions by BYJU'S is authentic and precise in the test point of view.

The affiliate explains about the nervous system, the different units of the nervous arrangement, neuron and its diverse parts. It also describes the different types of fretfulness.

• Sensory nerves: send messages from the sense organs to the brain or spinal cord.
• Motor fretfulness: comport letters dorsum from the brain or spinal cord to all the muscles and glands in the body.
• Mixed nerves: carry both sensory and motor nerves.

The chapter also explains about reflex activeness and reflex arcs. The detailed construction and function of a brain and the central nervous organization are also given in the chapter.

Download ICSE Class 8 Biology Selina Solutions PDF for Chapter 7 – The Nervous System

Multiple Choice Questions:

1. Put a tick mark against the correct culling in the post-obit statements:

(a) Medulla oblongata controls

1. Smelling

2. Beating of eye and respiratory movement

3. Intelligence and will power

4. Balancing the body

Answer: Beating of eye and respiratory motility

(b) Remainder of torso is controlled past:

ane. Spinal string

2. Cerebellum

iii. Cerebrum

4. Medulla

Reply: Cerebellum

(c) The smell of good nutrient causes watering of your mouth. It is a

1. Natural reflex

ii. Acquired reflex

3. Inborn reflex

four. Ordinary reflex

Reply: Acquired reflex

(d) The structural and functional unit of the nervous system is a

one. Axon

2. Nephron

three. Neuron

four. Texon

Answer: Nephron

Brusk Reply Questions:

Question 1.

Name the two types of coordination which accept identify in our body.

Solution:

(a) Nervous coordination: Past nerves and brain

(b) Chemical coordination: By hormones

Question ii.

You are driving your cycle at a fast speed. All of a sudden, a minor male child comes in front of your cycle and, without wasting any fourth dimension in thinking, you immediately apply the brakes and accident is avoided. What name is given to such an action?

Solution:

Reflex activity (acquired).

Question 3.

Given below is the diagram of a neuron. Proper name the parts numbered 1-five.

Solution:

1. Dendrite

ii. Nucleus

3. Cell Body (Nyton)

4. Axon (Nerve fibre)

v. Node of Ranvier

Question 4.

Write 1 word in the space provided to complete the 2nd pair of the related words pertaining to the nervous system.

Retentiveness: cerebrum:: breathing: ?

Balance: cerebellum:: reasoning: ?

Solution:

Retentiveness: cerebrum:: breathing: medulla oblongata

Balance: cerebellum:: reasoning: cerebrum

Question 5.

Differentiate between the post-obit pair of terms:

(a) Stimulus and impulse

Solution:

Stimulus: Any change in the surround that usually results in a alter in the activity of the trunk. Information technology is actually an influence.

Impulse: A wave of electric disturbance that runs through the fretfulness.

(b) Receptor and effector

Solution:

Receptor: The nerve cell on receiving the stimulus sets upwardly the waves of impulses towards the central nervous organisation.

Effector: Whatsoever muscle or gland volition contract or secrets when receiving an impulse from the brain.

(c) Motor nervus and sensory nervus

Solution:

Motor nerve: It contains merely motor neurons, Example: Fretfulness going to the muscles of the eyeball. Sensory nervus: It contains simply sensory neurons. Example: the optic nerve of the eye.

Question 6.

(a) Name the three major divisions of the human nervous system.

Solution:

1. The peripheral nervous system

2. The central nervous system

3. The autonomic nervous organization

(b) Proper noun the three chief parts of the human brain.

Solution:

i. Cerebrum

2. Cerebellum

3. Medulla oblongata

Question seven.

Give the role of each of the following:

(a) Olfactory nerve:

(b) Optic nerve:

(C) Facial nerve:

Solution:

(a) Olfactory nervus: The epithelial layers of the nasal chambers has a sense of smell. The sense of scent is carried to the brain by the olfactory nerve. They ascend from the anterior ends of the olfactory lobes and are distributed to the lining of nasal chambers.

(b) Optic nerve: optic nerves carries the reflection of the object from the retina to the brain. The paradigm formed on the retina is in a reverted position and the right picture is formed in the brain as the object is. The optic nerves arise from the side of the diencephalon. They innervate the retina of the eve and are sensory in nature.

(c) Facial nerve: Message and all expressions of the face, mastication work alone by the teeth, movement of the cervix and the activities of the salivary glands to the brain are carried by the facial nerve. It arises from the side of the medulla. On the whole facial nerves are mixed in nature.

Long Respond questions

Question 1.

With the aid of a suitable diagram depict the structures of a neuron.

Solution:

The nervous system consists of special cells called nerve cells or neurons. Cyton is the master cell body which gives out many processes called dendrites. From it, a very long procedure is given out. It is chosen axon or nerve fibre.

The jail cell body has a nucleus. The message from the organs and send this message to the axon through the cell trunk is organized by a jail cell body chosen dendrites. Then the axon sends the message to the musculus to contrast or to the gland for secretion.

The neurons make contact with one another through their processes. The axon at its end branches and meets the dendrites of some other neuron. The meeting point is chosen a synapse. The message is passed on from 1 axon to the dendrites of another neuron. How the bulletin goes?

It is like this:

Organ Message goes to dendrites Cell trunk Axon Muscles or glands

Question two.

Briefly draw the structure of the cerebrum in the homo brain and mention its functions.

Solution:

The brain consists of the chief 3 parts and lies in the cranial cavity of the skull.

1. The cerebrum

2. The cerebellum

3. The medulla oblongata

Cerebrum: It is very large and forms 2-thirds of the whole brain. A deep longitudinal groove separates the 2 hemispheres from each other is the median fissure. The outer surface is folded with ridges and grooves. The hemispheres are hollow from within and their walls accept outer and inner portions. The outer portion has prison cell bodies of the neurons and it is called grey affair. The wavery edges of the folded layer take numerous neurons to the extent of nine billion. The inner portion of the cerebrum has axons and information technology is called white affair.

Functions:

ane. Information technology controls all the voluntary activities.

2. It is the seat of intelligence, consciousness and will power.

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