NCERT Solutions for Class 10 Science Chapter 7

NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination intext questions answers on Page 119 or Page 122 or Page 125 and Exercises answers in English as well as Hindi Medium free to download in PDF.

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NCERT Solutions for Class 10 Science Chapter 7

Class:	10
Subject:	Science – Biology
Chapter 7:	Control and Coordination

10th Science Chapter 7 Answers in English & Hindi Medium

All Subjects NCERT Solutions for class 10 are in PDF and Free to download. NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination Intext questions and chapter end exercises question answers are given below to free download. All the answers are updated for session 2020-21 based on latest NCERT Books 2020-21 following the current CBSE Syllabus 2020-2021.

10th Science Chapter 7 Answers in English Medium
10th Science Chapter 7 Answers in Hindi Medium
10th Science Chapter 7 Answers in PDF Form

How does over production of hormones controlled? Give one example.

Endocrine glands or ductless glands produce hormones and directly pour their secretion in the blood. These glands do not go on producing hormones. Their secretion is controlled by feedback information system. Thus their over production of hormones is controlled.
For example, a hormone called TSH is secreted by pituitary gland. TSH stimulates the production of thyroxine from the thyroid gland. But if there is over production of thyroxine hormone, this hormone acts on pituitary gland and controls the production of TSH. As a result, the production of thyroxine by the thyroid gland is controlled. Thus, TSH and thyroxine control the level of each other. This mechanism of opposing effect is called feedback mechanism.

Differentiate between sensory neurons and motor neurons.

Sensory neurons carry sensory impulse from receptors to the nerve cell body or to the region which receives sensory impulses. Whereas motor neurons carry information of action to be carried by the conserved voluntary muscles.

How is brain protected in our body?

Human brain is lodged in a bony case, the cranium which protects it from injuries. It is wrapped in three sheets of connective tissue, known as meninges. The space between the meninges is filled with cerebrospinal fluid which helps in absorption of shocks.

Name the part of the brain responsible for precision of voluntary action and maintaining body posture and balance of the body.

Fore-brain is responsible for precision of voluntary action.
Cerebellum is responsible for maintaining the posture and keeping balance of the body.

What is the role of the brain in reflex action?

Reflex actions are controlled by spinal cord, although the information input also goes on to reach the brain. However, conditioned reflexes (based on previous experiences), such as salivation after seeing good food are controlled by cerebral cortex of brain.

How does adrenaline help an athlete to prepare for running?

Adrenaline causes the heart beat faster, resulting in supply of more oxygen. It causes reduction in supply of blood to the digestive system and skin. This diverts the blood to our skeletal muscle. The breathing rate also increases. All these responses together help an athlete to prepare for running.

What is meant by Tropic movement? Why do tropic movements takes place in plants?

The directional (tropic) response of plants shown by the plants towards or away of the stimulus such as light, water, gravity, etc. is known as tropism.
Tropic movements in plants are growth related. Plants respond to stimuli slowly by growing in a particular direction, either towards stimulus or away from. This growth causing tropic movement is regulated by the plant hormone called auxin.

Questions for Practice

Question:
State the function of any three of the structural and functional unit of nervous system.
Answer:
Nervous system: Main parts of nervous system are: (i) Central nervous system, (ii) Peripheral nervous system, (iii) Autonomous System.
(i) Central Nervous System: It consist of
(a) Brain receives information carrying impulses from all the sensory organs (by sensory nerves) of the body and also from the spinal cord. The brain respond to the information by sending its own instructions (through motor nerves) to the muscles and glands to act accordingly. The brain also stores information and act as organ of thought and intelligence.
(b) Spinal cord: It is concerned with spinal reflex actions and the conduction of nerve impulses to and from the brain.
(ii) Peripheral Nervous system: it is composed of cranial nerves (nerves from the brain) and the spinal nerves. Both of these consist of sensory and motor neurons. So, they carry sensations to and messages from the brain and the spinal cord.
(iii) Autonomous Nervous System: It is that part of the peripheral nervous system which controls the activities of the internal organs such as stomach, heart-beat, etc. automatically even without our thinking about them. Its nerves are attached to the smooth muscles and control the activities of internal organs of the body involuntarily, many these nerves are connected with the mid- brain and hind-brain.

Questions from Board Papers

Question 1:
(a) If the cerebellum is not functioning properly, state the activities of our body that are affected.
(b) how do muscles move?
Answer 1:
(a) Cerebellum is not functioning properly may affect-
(i)Walking in straight line
(ii)Riding a cycle
(iii)Maintaining the posture and balance of the body
(iv)Movement is very coordinate, the patient sways in walking and tend to fall towards the affected side.
(v)It is responsible for precision of voluntary actions.
(b) When the decision to move is conveyed by a nerve to a muscle, it has to act. In response to nervous electrical impulses. The special proteins of the muscle change both their shape and their arrangement in the cell. This new arrangement of these proteins give the muscle cells a shorter form that causes movement of the muscle.

Question 2:
“Use of iodised salt is essential”. List three reasons to justify this statement.
Answer 2:
(i) Iodised salt supplies sufficient amount of iodine through our diet, even in the areas where iodine is not available naturally through water or otherwise in diet.
(ii) Iodine is necessary for the thyroid glands to make thyroxine hormone.
(iii) Proper supply of iodine maintains thyroxine level that regulates carbohydrate, protein, and fat metabolism to provide the best balance for growth.
(iv) Deficiency of iodine causes many diseases such as Goitre.

Important Questions on 10th Science Chapter 7

What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?

Receptors are sensory structures (organs/tissues or cells) present all over the body. The receptors are either grouped in case of eye or ear, or scattered in case of skin. Functions of receptors:

They sense the external stimuli such as heat or pain.
They also trigger an impulse in the sensory neuron which sends message to the spinal cord. When the receptors are damaged, the external stimuli transferring signals to the brain are not felt. For example, in the case of damaged receptors, if we accidentally touch any hot object, then our hands might get burnt as damaged receptors cannot perceive the external stimuli of heat and pain.

How does phototropism occur in plants?

The movement of plant in response to light is called phototropism. Stem shows positive phototropism as follows: When growing plants detect light, a hormone called auxin, synthesised at the shoot tip, helps the cells to grow longer. When light is coming from one side of the plant, auxin diffuses towards the shady side of the shoot. This concentration of auxin stimulates the cells to grow longer on the side of the shoot which is away from light. Thus, the plant appears to bend towards light.

Which signals will get disrupted in case of a spinal cord injury?

The reflex arc connections between the input and output nerves meet in a bundle in the spinal cord. In fact, nerves from all over the body meet in a bundle in the spinal cord on their way to the brain. In case of any injury to the spinal cord, the signals coming from the nerves as well as the signals coming to the receptors will be disrupted.

How does chemical coordination occur in plants?

Plants respond to stimuli by showing movements. The growth, development, and responses to the environment in plants is controlled and coordinated by a special class of chemical substances known as hormones. These hormones are produced in one part of the plant body and are translocated to other needy parts. For example, a hormone produced in roots is translocated to other parts when required. The five major types of phytohormone are auxins, gibberellins, cytokinins, abscisic acid, and ethylene. These phytohormones are either growth promoters (such as auxins, gibberellins, cytokinins, and ethylene) or growth inhibitors such as abscisic acid.

What is the need for a system of control and coordination in an organism?

The maintenance of the body functions in response to changes in the body by working together of various integrated body systems is known as coordination. All the movements that occur in response to stimuli are carefully coordinated and controlled. In animals, the control and coordination movements are provided by nervous and muscular systems. The nervous system sends messages to and away from the brain. The spinal cord plays an important role in the relay of messages. In the absence of this system of control and coordination, our body will not be able to function properly. For example, when we accidentally touch a hot utensil, we immediately withdraw our hand. In the absence of nerve transmission, we will not withdraw our hand and may get burnt.

How are involuntary actions and reflex actions different from each other?

Involuntary actions cannot be consciously controlled. For example, we cannot consciously control the movement of food in the alimentary canal or pumping of blood through heart. These actions are however directly under the control of the brain. On the other hand, the reflex actions such as closing of eyes immediately when bright light is focused show sudden response and do not involve any thinking. This means that unlike involuntary actions, the reflex actions are not under the control of brain.

What is the difference between a reflex action and walking?

A reflex action is a rapid, automatic response to a stimulus. It does not involve any thinking. For example, we close our eyes immediately when the bright light is focused.

Walking, on the other hand, is a voluntary action. It is under our conscious control.

Which part of the brain maintains posture and equilibrium of the body?

Cerebellum, a part of hindbrain is responsible for maintaining posture and equilibrium of the body.

What is the role of the brain in reflex action?

Reflex actions are sudden responses, which do not involve any thinking. For example, when we touch a hot object, we withdraw our hand immediately without thinking as thinking may take time which would be enough to get us burnt. The sensory nerves that detect the heat are connected to the nerves that move the muscles of the hand. Such a connection of detecting the signal from the nerves (input) and responding to it quickly (output) is called a reflex arc. The reflex arcs –connections present between the input and output nerves − meet in a bundle in the spinal cord.
Reflex arcs are formed in the spinal cord and the information (input) reaches the brain. The brain is only aware of the signal and the response that has taken place. However, the brain has no role to play in the creation of the response.

What are plant hormones?

Plant hormones or phytohormones arenaturally-occurring organic substances. These are synthesized in one part of the plant body (in minute quantities) and are translocated to other parts when required. The five major types of phytohormones are auxins, gibberellins, cytokinins, abscisic acid and ethylene.
Gibberellins help in the growth of the stem.
Auxins help in the growth of the stem.
Cytokinins promote cell division.
Abscisic acid is one example of a hormone which inhibits growth.

How do auxins promote the growth of a tendril around a support?

These tendrils are sensitive to touch. When they come in contact with any support, auxin (a growth hormone) diffuses from the part of the tendril in contact with the object to other side, which is not in the contact. Therefore the part of the tendril in the contact with the object does not grow as rapidly as the part of the tendril away from the object. This causes the tendril to circle around the object and thus cling to it.

How does chemical coordination take place in animals?

Chemical coordination takes place in animals with the help of hormones. Hormone is the chemical messenger that regulates the physiological processes in living organisms. It is secreted by glands. The regulation of physiological processes and control and coordination by hormones comes under the endocrine system. The nervous system along with the endocrine system in our body controls and coordinates the physiological processes.

How does our body respond when adrenaline is secreted into the blood?

Adrenalin is a hormone secreted by the adrenal glands in case of any danger or emergency or any kinds of stress. It is secreted directly into the blood and is transported to different parts of the body.
When secreted in large amounts, it speeds up the heartbeat and hence supplies more oxygen to the muscles. The breathing rate also increases due to contractions of diaphragm and rib muscles. It also increases the blood pressure. All these responses enable the body to deal with any stress or emergency.

Why are some patients of diabetes treated by giving injections of insulin?

Diabetes is a disease in which the level of sugar in the blood is too high. Insulin, a hormone secreted by the pancreas, helps in regulating the blood sugar levels. This is the reason why diabetic patients are treated by giving injections of insulin.