Welcome to the NCERT Solutions for Class X Science Chapter 7, Control and Coordination. This chapter explores the complex system of control and coordination in living organisms. The chapter discusses the different components of the nervous system, the various types of neurons, and the role of the brain in controlling and coordinating bodily functions.
In this chapter, you will learn about the different types of receptors in the body, such as sensory receptors, and their role in sensing external and internal stimuli. You will also study the different types of hormones and their functions in maintaining homeostasis, growth, and development.
The NCERT Solutions for Class X Science Chapter 7 provide detailed explanations and step-by-step solutions to all the questions in the textbook. With the help of these solutions, you can clear your doubts and understand the concepts thoroughly. So, let’s dive into the fascinating world of control and coordination and learn how living organisms maintain balance and respond to changes in their environment.
Download PDF of NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination
Answers of Science NCERT solutions for class 10 Chapter 7 Control and Coordination
Chapter 7
Control and Coordination
Intext Questions
Question 1:
What is the difference between a reflex action and walking?
Answer:
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.
Question 2:
What happens at the synapse between two neurons?
Answer:
A very small gap that occurs between the last portion of the axon of one neuron and the dendron of the other neuron is known as a synapse. It acts as a one way valve to transmit impulses in one direction only. This uni-direction transfer of impulses occurs as the chemicals are produced in only one side of the neuron i.e., the axon’s side. From the axon, the impulses travel across the synapse to the dendron of the other neuron.
A synapse or neuromuscular junction
Question 3:
Which part of the brain maintains posture and equilibrium of the body?
Answer:
Cerebellum, a part of the hindbrain is responsible for maintaining posture and equilibrium of the body.
Question 4:
How do we detect the smell of an agarbatti (incense stick)?
Answer:
The thinking part of our brain is the forebrain. It has separate areas that are specialized for hearing, smelling, sight, taste, touch, etc. The forebrain also has regions that collect information or impulses from the various receptors. When the smell of an incense stick reaches us, our forebrain detects it. Then, the forebrain interprets it by putting it together with the information received from other receptors and also with the information already stored in the brain.
Question 5:
What is the role of the brain in reflex action?
Answer:
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 arc
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
Question 1:
What are plant hormones?
Answer:
Plant hormones or phytohormones are naturally-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.
Question 2:
How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light?
Answer:
The movement of leaves of the sensitive plant, Mimosa pudica or “touch me not”, occurs in response to touch or contact stimuli. This movement is independent of growth. The movement of shoot towards light is known as phototropism. This type of movement is directional and is growth dependent.
Question 3:
Give an example of a plant hormone that promotes growth.
Answer:
Auxin is an example of growth-promoting plant hormone.
Question 4:
How do auxins promote the growth of a tendril around a support?
Answer:
Auxin is synthesized at the shoot tip. It helps the cell grow longer. When a tendril comes in contact with a support, auxin stimulates faster growth of the cells on the opposite side, so that the tendril forms a coil around the support. This makes the tendrils appear as a watch spring.
Question 5:
Design an experiment to demonstrate hydrotropism.
Answer:
Take two small beakers and label them as A and B. Fill beaker A with water. Now make a cylindrical-shaped roll from a filter paper and keep it as a bridge between beaker A and beaker B, as shown in the figure. Attach a few germinating seeds in the middle of the filter paper bridge. Now, cover the entire set-up with a transparent plastic container so that the moisture is retained.
Observation:
The roots of the germinating seeds will grow towards beaker A.
This experiment demonstrates the phenomenon of hydrotropism.
Question 1:
How does chemical coordination take place in animals?
Answer:
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.
Question 2:
Why is the use of iodised salt advisable?
Answer:
Iodine stimulates the thyroid gland to produce thyroxine hormone. It regulates carbohydrate, fat, and protein metabolism in our body. Deficiency of this hormone results in the enlargement of the thyroid gland. This can lead to goitre, a disease characterized by swollen neck. Therefore, iodised salt is advised for normal functioning of the thyroid gland.
Question 3:
How does our body respond when adrenaline is secreted into the blood?
Answer:
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.
Question 4:
Why are some patients of diabetes treated by giving injections of insulin?
Answer:
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.
Exercises
Question 1:
Which of the following is a plant hormone?
- Insulin
- Thyroxin
- Oestrogen
- Cytokinin
Answer:
(d) Cytokinin is a plant hormone.
Question 2:
The gap between two neurons is called a
- dendrite.
- synapse.
- axon.
- impulse.
Answer:
(b) The gap between two neurons is called a synapse.
Question 3:
The brain is responsible for
- thinking.
- regulating the heartbeat.
- balancing the body.
- all of the above.
Answer:
(d) The brain is responsible for thinking, regulating the heartbeat and balancing the body.
*Question 4:
What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?
Answer:
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.
*Question 5:
Draw the structure of a neuron and explain its function.
Answer:
Neurons are the functional units of the nervous system. The three main parts of a neuron are axon, dendrite, and cell body.
Structure of a neuron
Functions of the three parts of a neuron:
Axon: It conducts messages away from the cell body.
Dendrite: It receives information from the axon of another cell and conducts the messages towards the cell body.
Cell body: It contains nucleus, mitochondria, and other organelles. It is mainly concerned with maintenance and growth.
Question 6:
What are the changes seen in girls at the time of puberty?
Answer:
Secondary sexual characteristics in girls:
- Increase in breast size and darkening of skin of the nipples present at the tips of the breasts.
- Appearance of hair in the genital area.
- Appearance of hair in other areas of skin like underarms, face, hands, and legs.
- Increase in the size of the uterus and ovary.
- Beginning of menstrual cycle.
- More secretion of oil from the skin, which results in the appearance of pimples.
*Question 7:
Which signals will get disrupted in case of a spinal cord injury?
Answer:
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.
*Question 8:
How does chemical coordination occur in plants?
Answer:
In animals, control and coordination occur with the help of the nervous system. However, plants do not have a nervous system.
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.
*Question 9:
What is the need for a system of control and coordination in an organism?
Answer:
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.
Question 10:
How are involuntary actions and reflex actions different from each other?
Answer:
Involuntary actions cannot be consciously controlled. For example, we cannot consciously control the movement of food in the alimentary canal. 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 the brain.
*Question 11:
Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
Answer:
| Nervous system mechanism | Hormonal system mechanism | ||
| 1. | The information is conveyed in the form of electric impulse. | 1. | The information is conveyed in the form of chemical messengers. |
| 2. | The axons and dendrites transmit the information through a coordinated effort. | 2. | The information is transmitted or transported through blood. |
| 3. | The flow of information is rapid and the response is quick. | 3. | The information travels slowly and the response is slow. |
| 4. | Its effects are short lived. | 4. | It has prolonged effects. |
Question 12:
What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?
Answer:
| Movement in sensitive plants | Movement in our legs | ||
| 1. | The movement that takes place in a sensitive plant such as Mimosa pudica occurs in response to touch (stimulus). | 1. | Movement in our legs is an example of voluntary actions. |
| 2. | For this movement, the information is transmitted from cell to cell by electro- chemical signals as plants do not have any specialised tissue for conduction of impulses. | 2. | The signal or messages for these actions are passed to the brain and hence are consciously controlled. |
| 3. | For this movement to occur, the plant cells change shape by changing the amount of water in them. | 3. | In animal muscle cells, some proteins are found which allow the movement to occur. |
Access Answers of Science NCERT Class 10 Chapter 7 Control and Coordination
Questions Page number 119
1. What is the difference between a reflex action and walking?
Solution:
Reflex action are the involuntary actions that occur in response to stimuli. They occur without involvement of conscious areas of brain. All the reflex actions are unconscious actions. Reflex action occurs brain and spinal cord of central nervous systems.
On the other hand voluntary actions are those which occur under the control of cerebellum of the brain Walking is learnt as we grow. Walking is controlled by brain as is used when required.
2. What happens at the synapse between two neurons?
Solution:
Between the synapse between two neurons electric signals are converted into chemicals that can easily cross over the gap and pass on the chemical messenger to next neuron where it is converted back to electrical signal.
3. Which part of the brain maintains posture and equilibrium of the body?
Solution:
Cerebellum which is a part of the brain is responsible for Controls the motor functioning hence it is the part reengaged in the maintenance of posture and equilibrium of the body.
4. How do we detect the smell of an agarbatti (incense stick)?
Solution:
Smell of an agarbatti is detected by nose, olfactory receptors present in the nose sends electrical signal to the fore brain. Fore brain interprets this signal as the incense stick to be detected as smell.
5. What is the role of the brain in reflex action?
Solution:
Reflex actions are formed instantaneously in response to the stimulus that has no time to think. For instance 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 known as reflex arc.
Reflex action are generated in spinal cord and the information also reaches brain. This helps the brain to record this event and remember it for future use. Brain helps the person to get awareness of the stimulus and prevent himself from that situation again.
Questions Page number 119
1. What are plant hormones?
Solution:
Plant hormones are the organic substances produces at certain sites of the plant and are translocated to other parts based on the requirement. Plant hormones help to coordinate growth, development and responses to the environment. Ex: Auxin’s Gibberlin’s, cytokines, abscisic acid and ethylene.
2. How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light?
Solution:
| Sl. no | Movement of leaves of the sensitive plant | Movement of a shoot towards light |
| 1 | It does not depend on the direction of stimulus applied. | Depends on the direction of stimulus applied. |
| 2 | Called as Nastic movement | Called as tropic movement |
| 3 | Touch is the stimulus | Light is the stimulus |
| 4 | Caused by the sudden loss of water from the swellings at the base of leaves | Caused by the unequal growth on the two sides of the shoot. |
| 5 | Not a growth movement | Growth movement |
| 6 | Occurs very fast | Occurs slowly |
3. Give an example of a plant hormone that promotes growth
Solution:
Auxins and Gibberlins are the hormone responsible for the growth of plant.
Auxins are responsible for the cell elongation in shoot and also regulates growth.
Gibberlin is responsible for stem elongation and germination.
4. How do auxins promote the growth of a tendril around a support?
Solution:
Auxins are the plant hormones produces at the tip of a shoot and root. Auxins are present at the tip of tendrils. When tendrils are attached around any support their growth is slowed down as auxins are sensitive to touch. This make them move to the other side of the tip to get support this makes the other side grow faster than the side of tendril in contact with the support and the tendril bends towards the support.
5. Design an experiment to demonstrate hydrotropism.
Solution:
To demonstrate hydrotropism in plants.
Procedure :
i. Plant a seedling in a vessel containing soil.
ii. Adjacent to the seedling put a porous pot containing water.
iii. Leave the set up for few days.
Observation :
iv. On examining the roots it is observed that the roots bend towards the source of water and do not grow straight.
result :
It confirms that plant shows hydrotropism as the roots bend towards the porous pot of water. As hydrotropism is a plant growth response in which the direction of growth is determined by a stimulus of gradient in water concentration.
Questions Page number 125
1. How does chemical coordination take place in animals?
Solution:
Chemical coordination takes place in animals with the help of chemical messengers called as hormones. Hormones are the chemic fluids that are secreted by specific glands of the endocrine gland. Hormones regulate the growth, development and homeostasis of the animals.
2. Why is the use of iodized salt advisable?
Solution:
Usage of Iodized salt is advisable to avoid the deficiency of Iodine. If the intake of iodine is low, the release of thyroxine from the thyroid gland will be decreased. This affects fat, carbohydrate and protein metabolism. Thus a person may have goitre problem in case if the intake of iodine is lowered.
3. How does our body respond when adrenaline is secreted into the blood?
Solution:
Adrenaline is a hormone secreted when a person is frightened or mentally disturbed. When Adrenaline reaches heart, heartbeat will increase to increase blood supply to our muscles. Adrenaline also increases the breathing rate because of contraction of diaphragm and the rib muscles. Adrenaline rush also increases blood pressure and allows entry of more glucose into blood. These altogether occurs when our body respond to secretion of adrenaline into our blood.
4. Why are some patients of diabetes treated by giving injections of insulin?
Solution:
Diabetes is a condition where insulin hormone is produced less or stopped by pancreatic cells of a person. Insulin regulates blood glucose by converting extra glucose to glycogen. When insulin is not produced adequately person blood glucose level which leads to adverse effects. In order to maintain the insulin and blood glucose level diabetes patients are treated with injections of insulin.
Exercise Questions Page number 126
1. Which of the following is a plant hormone?
(a) Insulin
(b) Thyroxin
(c) Oestrogen
(d) Cytokinin
Solution:
Answer is d) cytokinin.
Cytokinin is a plant hormone whereas Insulin, Thyroxin, Oestrogen are the hormones produced by animals.
2. The gap between two neurons is called a
(a) Dendrite.
(b) Synapse.
(c) Axon.
(d) Impulse.
Solution:
Answer is (b) Synapse
Dendrite is a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body.
An axon or nerve fiber is a long, slender projection of a nerve cell or neuron in vertebrates that typically conducts electrical impulses known as action potentials away from the nerve cell body. The function of the axon is to transmit information to different neurons, muscles, and glands.
Impulse an electrical signal that travels along axon.
3. The brain is responsible for
(a) Thinking.
(b) Regulating the heartbeat.
(c) Balancing the body.
(d) all of the above.
Solution:
Answer is (d) all the above
Brain is responsible for thinking, brain regulates the heartbeat, and it balance the body.
4. What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?
Solution:
Receptors are present throughout our body mainly sense organs. Receptors collect the information about changes that happen around us and send the signal to information to brain which render effector mechanism against the change. When receptors do not work properly, the environmental stimuli are not able to create nerve impulses and body does not respond.
5. Draw the structure of a neuron and explain its function.
Solution:
Neurons are nerve cells which are functional units of the nervous system. Three main parts of neurons are Dendrites, Axons and cell body.
Dendrite: Detects information and sends it to cell body
Cell Body: Maintains growth of the cell
Axon: Conducts messages away from cell body and signal to next neuron.
6. How does phototropism occur in plants?
Solution:
Directional movement and growth of plant in response to light is called as phototropism. Phototropism occurs due to increased auxin on the dark side and decreased auxin on the illuminated side. Because of presence of more auxin, leaf in the darker side grows faster causing it to bend towards the source of light.
7. Which signals will get disrupted in case of a spinal cord injury?
Solution:
In case of a spinal cord injury, signals coming from the nerves as well as the signals coming to the receptors will be disrupted. Both these signals meet in a bundle in the spinal cord. Hence, both these signals get disrupted.
8. How does chemical coordination occur in plants?
Solution:
Plant growth, development and responses to the environment is controlled and coordinated by a special class of chemical substances known as hormones. Hormones are produced in one part of the plant and are transported to all the needy parts of the plant. 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.
9. What is the need for a system of control and coordination in an organism?
Solution:
There are various organs in an organism. These organs must be carefully controlled and coordinated for the survival of an organisms. In the body of an organism various fluids are secreted from the glands of the endocrine system. These hormones are responsible for the overall growth and development of an organism. All others daily decision that includes voluntary and involuntary action are controlled by central nervous system (CNS).
Coordination is needed for all human activities we perform. Our nervous system receives information from surroundings which is processed and response is ilicited. The endocrine system (hormonal system) helps in integrating various metabolic activities like reproduction, development, and all reflex actions (cope up with various give up situations).
The hormonal system in plants helps in process of photosynthesis; they need carbon dioxide, water and sunlight. The stomatal opening in leaves opens up to allow in carbon dioxide gas, the roots bend towards water and the stem grows towards sunlight, the tendrils in climbing pants are supported by the hormonal system of the plant body.
Thus, we need of control and coordination system in an organisms.
10. How are involuntary actions and reflex actions different from each other?
Solution:
| Reflex actions | Involuntary actions |
| 1. Rapid automatic responses to a stimulus without the conscious involvement of the brain | 1. Occurs without the consciousness of an organism |
| 2. Controlled by spinal cord | 2. Controlled by mid brain or medulla oblongata |
| 3. Very quick and instantaneous | 3. Relatively slower |
| 4. May involve any muscle or a gland | 4. Involves only smooth muscles |
| 5. Can be conditioned | 5. Cannot be influenced by external conditioning |
| Examples: Blinking of eyes, salivation | Examples: Beating of heart, blood circulation |
11. Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
Solution:
| Nervous control | Hormonal Control | ||
| 1 | It is consist of nerve impulses between PNS, CNS and Brain. | 1 | It consists of endocrine system which secretes hormones directly into blood. |
| 2 | Here response time is very short. | 2 | Here response time is very long. |
| 3 | Nerve impulses are not specific in their action. | 3 | Each hormone has specific actions. |
| 4 | The flow of information is rapid. | 4 | The flow of information is very slow. |
12. What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?
Solution:
| Sl. no | Movement in sensitive plants | Movement in our legs | |
| 1 | The movement in a sensitive plant is a response to stimulus (touch) which is an involuntary action. | 1 | Movement in our legs is a voluntary action. |
| 2 | No special tissue is there for the transfer of information | 2 | A complete system CNS and PNS is there for the information exchange. |
| 3 | Plant cells do not have specialized protein for movements. | 3 | Animal cells have specialized protein which help muscles to contract. |
NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination
NCERT Solutions for Class 10 Science Chapter 7 explains the nervous system-muscular tissue correlation. This topic also explains the human brain anatomy, tissue protection and nervous tissue action. It briefs animals and plants chemical coordination. NCERT Solution for Class 10 Science Chapter 7 control and coordination explains some of the important hormones and their functions. Concepts were explained with a clear diagram showing the location of different glands in the human body and a table on the functions of different glands.
Conclusion
NCERT Solutions for Class X Science Chapter 7, Control and Coordination, is an essential chapter that provides a comprehensive understanding of the complex system of control and coordination in living organisms. The chapter explains the different components of the nervous system, including the brain, spinal cord, and peripheral nerves, and their role in controlling and coordinating bodily functions.
The chapter also delves into the different types of receptors in the body, including sensory receptors, and their role in sensing external and internal stimuli. It also discusses the different types of hormones and their functions in maintaining homeostasis, growth, and development.
Furthermore, the chapter highlights the importance of maintaining balance and responding to changes in the environment for survival. It emphasizes the significance of scientific research in the study of the nervous system and hormonal control in living organisms.
Overall, NCERT Solutions for Class X Science Chapter 7, Control and Coordination, is an essential resource for students who want to gain a comprehensive understanding of the control and coordination mechanisms in living organisms. The solutions provided in this chapter help students to clear their doubts and understand the concepts thoroughly. It also provides a strong foundation for further studies in biology and related fields.
- For Class 10 Science chapter 7 explains the various nervous action like
- Reflux action
- Voluntary action
- Involuntary action
- It explains the control and coordination of the nervous system.
- The action of hormones is regulated by the feedback mechanism.
- Use of electrical impulses to transmit messages.
Key Features of NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination:
- Students can easily understand the language used in NCERT solutions.
- For CBSE board exams, Science Olympiads, and other competitive exams, these solutions will be useful.
- Provides fully resolved solutions to all the issues in the respective NCERT textbooks.
- After extensive research on each topic, these solutions are prepared by our subject experts to provide the students with adequate and genuine information.
- To assist students in their preparations, detailed answers to all questions are provided.
