i am uploading the notes of control and coordination for my students of std 10th till the topic
"THE NERVOUS SYSTEM" and a small portion of magnetism.
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CONTROL AND COORDINATION  

           (By ABHISHEK SIR)

Q 1. What is control?

Ans. In biological sense, the word control means some restrain or regulation that can start, stop, slow

         down or speed up certain activities in the body.

Q2. What is coordination?

Ans. The orderly and harmonious activities of two or more cells, tissues, organs, etc. in the body for the

         Efficient activities for survival are known as coordination.

Q3. Differentiate between plant and animal control and coordination.

Ans. Since the internal structure of animals is much complex as compared to plants in having oxygen,

         Organ system, etc., they need a better control and coordination system than plants.

                                     Animals give quicker responses, while plants give slow response, which is largely

         because animals have two systems for control and coordination while plants have only one.

        A) Animals- i) Nervous system- nerve cells

                                  ii) Hormonal system- (endocrine glands - hormones)

       B) Plants- Hormonal System

NERVOUS SYSTEM

Nervous System - The system in the body that enables to give suitable responses to the internal and external changes for maintaining optimum condition in the body is called ‘’nervous system’’.

·         Nervous system is made up of a special tissue called nervous tissue.

·         The nervous tissue is made up of special cells called ‘’neurons’’.

·         Nervous tissue is specialized for receiving, conducting, analyzing and responding to various stimuli.

Grey matter -    cyton ; brain- outside & spinal cord-inside

White matter - axon which is made up of white myelin sheath.

Q4. Define control and coordination.

Ans. Control can be defined as regulatory mechanism which can start, stop, speed up and slow

         down different biological activities in an organism.

         The synchronization between the activities of different organ systems can be termed as

        coordination.  

Q5. How control and coordination is established in animals?

Ans. Control and coordination in animals is performed by-

a)      The nervous system

b)      The endocrine system (hormones)

·         One way of control may affect the other.

·         The communication in nervous system is via nerve impulse that travels through neurons in the body.

·         The Endocrine system consists of endocrine glands that secrets hormones which travel in  the body through blood.

·         A number of interactions between the environment and animals are a result of combined action of both nervous and endocrine system.

Q. Define:-

a) Sensitivity – The ability of an organism to detect changes and make appropriate response is called sensitivity.

b) Stimulus – Anything to which an organism reacts or responds is called stimulus.

c) Receptor – The part of the sense organ which receives a stimulus is called a receptor.

d) Response – The reaction of an organism towards a stimulus or stimuli is called response.

e) Effector – The organ of a living organism which responds towards a stimulus or stimuli is an effector organ.

Q. What are the different organs of nervous system?

Ans. The nervous system consists of:

     i)The central nervous system- Brain, Spinal cord

    ii) Peripheral nervous system- Cranial nerves (12 pairs), Spinal nerves (31 pairs)

   iii) Autonomic nervous system- Sympathetic N.S., Parasympathetic N.S.

Q. What is the fundamental unit of nervous system?

Ans.  Neurons  or nerve cells.

Q. Draw a neat and labeled diagram of neurons and explain its structure and function.

This impulse travels from dendrites to cell’s body and then along the axon to its end. At the end of the axon, the electrical impulses are released along with some chemicals messenger like ‘’acetylcholine’’. This chemical messenger crosses the synapse and start the similar electric impulse in the dendrites of next neurons. Because of this these chemicals are called ‘’neurotransmitter’’. A similar synapse between neuron and muscle cells (effector cells) called neuro-muscular junction which delivers the impulse into the muscles. This is the general scheme of how electrical impulse travels along the body.

Q. What is reflex action?

Ans. Reflex action is rapid, automatic response of the body towards stimulus without involving the brain. These actions are unconscious and involuntary.

 Q. Explain reflex arc.

Ans. The pathway of nerve involved in reflex action is called reflex arc. The impulse in a reflex move in a single direction only. A reflex arc is formed by a sensory nerve and a motor nerve joined by a connecting nerve present in the spinal cord. As the impulses do not have to travel all the way to the brain and back, detection of a stimuli and completion of response is faster.

Q. Explain the different components of brain.

Ans. Brain is divided into three main parts-

1)      Fore brain

2)      Mid brain

3)       Hind brain

1) Fore Brain – It is the main part of the brain. It is divided into 3 sub parts – cerebrum, thalamus & hypothalamus.

a)      Cerebrum

·         It is the most complex and largest part of the brain.

·         The outer region of the cerebrum is made up of nerve cells, called ‘’cerebral cortex’’.

·         It has no. of infoldings that increases its surface area.

·         Cerebrum is divided into two parts i.e. left and right cerebral hemisphere. These two hemispheres are joined together by a thick nerve fibre called ‘’corpus callosum’’.

·         Each cerebral hemisphere is divided into four lobes as given below-

a)      Frontal lobe – visual perception

b)      Parietal lobe – auditory perception

c)       Occipital lobe – perception of general sensation like touch

d)      Temporal lobe – muscular activities (both voluntary and involuntary)

b)      Thalamus-

·         It is located below the cerebral hemisphere.

·         It acts as a relay station for all sensory information going to the cerebrum. [Note- Relay station means that it passes the received signals to correct part of cerebrum].

c) Hypothalamus-

·         It is a small area present below the thalamus. Hence, it is called hypothalamus [hypo means below].

·         It regulates and controls the heartbeat, blood pressure, thirst, hunger and peristalsis. It acts as a connecting link between the endocrine and nervous system, because it is connected to the pituitary gland and controls it.

2) Mid Brain-

·         It is present in the middle of the forebrain. Hence, it is known as mid-brain.

·         It controls the reflexes of eyes [pupil’s eyes, ears and head].

·         It contains the optic lobes.

3) Hind Brain-

·         It is present behind the forebrain and midbrain. Hence, named as hind brain.

·         It has three parts- cerebellum, pons of verolli and medulla oblongata.

a)      Cerebellum-

·         It is a leaf-like structure and the largest part of the hind brain. It is situated behind the pons and medulla oblongata.

·         It maintains body balance and posture.

·         It controls and coordinates the voluntary muscular body movements.Alcohol affects the cerebellum adversely. So, the person who is drunk cannot stand properly.

b)      Pons-

·         It is present in front of the cerebellum and above medulla oblongata.

·         It acts as a bridge between brain and spinal cord.

·         Pons means bridge.

c)       Medulla Oblongata-

·         It is the lowermost portion of the brain.

·         It is roughly triangular and joins the spinal cord.

·         It is a reflex centre to control the activities like swallowing, vomiting, breathing, coughing, sneezing and heart beat.

·         It also controls sleep, consciousness, heartbeat and activities of cerebrum.

      Q. How are the brain and spinal cord protected?

·         The brain is present in a bony case called cranium or skull that protects it from external injury.

·         It is covered with three membranes called Meninges. These are-

a) Dura Matter- It is the toughest outermost membrane.

b) Arachnoid Matter- It is the middle membrane.

c) Pia Matter- It is the soft innermost membrane.

·         The space between the meninges and the brain is filled with a fluid called Cerebro-Spinal fluid [CSF]. It protects the brain from mechanical shock.

·         Spinal cord is present in the vertebral column called backbone.

·         This vertebral column protects the spinal cord.

·         Like brain, spinal cord is also protected with three meninges. CSF is also present between the three meninges to protect it from mechanical shock.

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