NCERT exemplar Class 10 Science solutions chapter 7 analyses and observe the movement of an organism. An important question that has always attracted philosophers in history was: “What is the reason for movement by any being and how it is controlled?”
Scientists and philosophers interpreted after the close observation that any motion or movement is the response to the environment. Keeping in mind the best process flow, our subject matter experts have painstakingly developed the NCERT exemplar Class 10 Science chapter 7 solutions. It contains the answers of all NCERT Class 10 Science Book Questions.
This Story also Contains
- NCERT Exemplar Class 10 Science Solutions Chapter 7-MCQ
- NCERT Exemplar Class 10 Science Solutions Chapter 7-Short Answer
- NCERT Exemplar Class 10 Science Solutions Chapter 7-Long Answer
- NCERT Exemplar Solutions Class 10 Science Chapter 7 Important Topics:
- NCERT Class 10 Science Exemplar Solutions for Other Chapters:
- Features of NCERT Exemplar Class 10 Science Solutions Chapter 7:
NCERT Exemplar Class 10 Science Solutions Chapter 7-MCQ
Question:1
Which of the following statements is correct about receptors?
(a) Gustatory receptors detect taste while olfactory receptors detect smell
(b) Both gustatory and olfactory receptors detect smell
(c) Auditory receptors detect smell and olfactory receptors detect taste
(d) Olfactory receptors detect taste and gustatory receptors smell
Answer: A
Solution: A receptor is a cell or group of cells that help in detecting external stimuli.
Gustatory receptors are taste receptors present on the papillae of the tongue. Olfactory receptors help in detecting smell and are present on the roof of the nasal cavity. Both the receptors send the information to the brain to interpret the stimulus and generate an appropriate response. Auditory receptors in ears help in detecting voices.
Question:3
In a synapse, chemical signal is transmitted from
(a) dendritic end of one neuron to axonal end of another neuron
(b) axon to cell body of the same neuron
(c) cell body to axonal end of the same neuron
(d) axonal end of one neuron to dendritic end of another neuron
Answer: D
Solution: Neurons communicate with one another at junctions called synapse. In a synapse, the electrical signal is converted into the chemical substance called as neurotransmitter by the presynaptic neuron.
This chemical diffuses across the synaptic cleft and reaches the other neuron. The signal thus travels from axonal end of one neuron to dendritic end of another neuron.
Question:4
In a neuron, conversion of electrical signal to a chemical signal occurs at/in
(a) cell body
(b) axonal end
(c) dendritic end
(d) axon
Answer: B
Solution: The signals are transferred from one neuron to another with the help of synapse. The electrical signals are very fast as compared to that of chemical signals. At the axonal end, the electrical signal is converted into a chemical signal with the help of chemical messengers called neurotransmitters that are received by the receptors present on the dendrites of another neuron.
Question:6
Which of the following statements are true?
(i) Sudden action in response to something in the environment is called reflex action
(ii) Sensory neurons carry signals from spinal cord to muscles
(iii) Motor neurons carry signals from receptors to spinal cord
(iv) The path through which signals are transmitted from a receptor to a muscle or a gland is called reflex arc \
(a) (i) and (ii)
(b) (i) and (iii)
(c) (i) and (iv)
(d) (i) , (ii) and (iii)
Answer: C
Solution: The statements (ii) and (iii) are false because sensory neurons carry signals from receptors to spinal cord and motor neurons carry signals from spinal cord to the muscles.
The statement (i) and (iv) are true.
Question:7
Which of the following statements are true about the brain?
(i) The main thinking part of brain is hind brain
(ii) Centres of hearing, smell, memory, sight etc are located in fore brain.
(iii) Involuntary actions like salivation, vomiting, blood pressure are controlled by the medulla in the hind brain
(iv) Cerebellum does not control posture and balance of the body
(a) (i) and (ii)
(b) (i), (ii) and (iii)
(c) (ii) and (iii)
(d) (iii) and (iv)
Answer: C
Solution: Hindbrain forms the lower part of brain stem and it consists of medulla oblongata, pons, and cerebellum.
Medulla oblongata controls involuntary actions such as heartbeat, breathing etc. Cerebellum helps in maintaining posture, balance, and equilibrium. Cerebrum forms part of the forebrain and is the main thinking part of the brain. It coordinates the voluntary actions of the body. It has different areas for performing functions such as centres of hearing, smell , memory, etc.
Question:8
Posture and balance of the body is controlled by
(a) cerebrum
(b) cerebellum
(c) medulla
(d) pons
Answer: B
Solution: Cerebellum is the part of the hindbrain and plays a major role in coordinating voluntary motor movements of the body. It also helps in maintaining balance and equilibrium. Cerebellar damage causes disorder in coordination, speed, posture and motor learning.
Question:9
Spinal cord originates from
(a) cerebrum
(b) medulla
(c) pons
(d) cerebellum
Answer: B
Solution: The brain is subdivided into cerebrum, thalamus, hypothalamus, cerebellum and brain stem. Brain stem consists of midbrain, pons and medulla oblongata. The medulla oblongata is the lowest part of the brain stem from where the spinal cord originates. Spinal cord is a long cylindrical structure consisting of bundle of nerve fibres, running through the vertebral column of the backbone.
Question:10
The movement of shoot towards light is
(a) geotropism
(b) hydrotropism
(c) chemotropism
(d) phototropism
Answer: D
Solution: Tropism is the growth in response to external stimuli. Geotropism is the growth of roots towards the gravitational force of the earth. Hydrotropism is the growth of shoots towards water. Chemotropism is the growth of shoots towards the chemical stimulus. Phototropism is the growth of shoots towards the direction of the light.
Question:11
The main function of abscisic acid in plants is to
(a) increase the length of cells
(b) promote cell division
(c) inhibit growth
(d) promote growth of stem
Answer: C
Solution: Abscisic acid is the plant hormone. It is also called as stress hormone because it shows different responses in the stress conditions. It leads to the seed dormancy and ensures seed germination only when favourable conditions return. It also causes the closing of stomata when plant doesn’t get enough water.
Question:12
Which of the following is not associated with growth of plant?
(a) Auxin
(b) Gibberellins
(c) Cytokinins
(d) Abscisic acid
Answer:
Answer: D
Solution: Abscisic acid is the stress hormone that causes different plant responses acting against stress conditions. It is responsible for dormancy of seeds and inhibition of seeds. It stimulates the closure of stomata, inhibit shoot growth, stimulate the storage of proteins in seeds, and so on.
Question:13
Iodine is necessary for the synthesis of which hormone?
(a) Adrenaline
(b) Thyroxin
(c) Auxin
(d) Insulin
Answer: B
Solution: Thyroid gland secretes a hormone thyroxine or T4 into the bloodstream. The major function of the thyroid gland is to produce thyroid hormones required by the body for metabolism. Iodine is required to make thyroid hormone. If iodine is not available in the diet, the thyroid gland may produce an insufficient amount of hormone.
Question:14
Choose the incorrect statement about insulin
(a) It is produced from pancreas
(b) It regulates growth and development of the body
(c) It regulates blood sugar level
(d) Insufficient secretion of insulin will cause diabetes
Answer:
The answer is option (b)
AS insulin doesn't regulate the growth and development of the body.
Question:15
Select the mis-matched pair
(a) Adrenaline : Pituitary gland
(b) Testosterone: Testes
(c) Estrogen : Ovary
(d) Thyroxin : Thyroid gland
Answer: A
Explanation: Adrenaline is a hormone produced by the adrenal glands and triggers the body's fight-or-flight response while pituitary gland produces growth hormone.
Testosterone is a hormone produced by the testes in males and is responsible for the development of male sexual characteristics.
Estrogen is produced by ovaries in the females and is responsible for the development of female sexual characteristics.
Thyroxine is produced by thyroid gland whose function is to regulate the metabolism in the cells of the body.
Question:16
The shape of guard cells changes due to change in the
(a) protein composition of cells
(b) temperature of cells
(c) amount of water in cells
(d) position of nucleus in the cells
Answer: C
Solution: Stomata is a pore like structure present on the epidermis of the leaves. It is guarded by the guard cells that help to regulate the rate of transpiration by opening and closing the stomata. If the guard cells are turgid or swollen, the stomatal opening is large. This turgidity is caused by the accumulation of K+ ions in the guard cells.
As K+ levels increase in the guard cells the water potential of the guard cells drops and water enters the guard cells. In the second case, the guard cells have lost water, which causes the cells to become flaccid and the stomatal opening to close. This may occur when the plant has lost an excessive amount of water.
Question:17
The growth of tendril in pea plants is due to
(a) effect of light
(b) effect of gravity
(c) rapid cell divisions in tendrillar cells that are away from the support
(d) rapid cell divisions in tendrillar cells in contact with the suppor
Answer: C
Solution: Pea plants grow in winters when the days are shorter and the exposure to sunlight is less. Tendrils are hair-like structures that grow with the help of any support so, they are not seen to grow with the impact of gravity.
On the other hand, tendrils that come in contact with the side of the object grows slowly and the side opposite to it is seen to grow at a very fast rate which causes rapid division of cells on the opposite side. This causes tendril to bend to the side where it touches the object and helps in clinging and does not flow with the wind.
Question:18
The growth of pollen tubes towards ovules is due to
(a) hydrotropism
(b) chemotropism
(c) geotropism
(d) phototropism
Answer: B
Solution: Chemotropism is growth towards the chemical stimulus. For fertilization to take place, pollen grains follow chemotropic mechanism where the growth of the pollen tube is towards the ovules. During fertilization, ovary release chemicals that trigger the chemotropic response from developing pollen tube. Hydrotropism is growth towards water, phototropism is towards the light, and geotropism is towards force of gravity.
Question:19
The movement of sunflower in accordance with the path of sun is due to
(a) phototropism
(b) geotropism
(c) chemotropism
(d) hydrotropism
Answer: A
Solution: Tropism is growth towards an external stimulus. It is of different types. In phototropism, the growth of plant is towards the direction of light. Thus, the movement of sunflower in accordance with the path of sun is due to phototropism.
Question:20
The substance that triggers the fall of mature leaves and fruits from plants is due to
(a) auxin
(b) gibberellin
(c) abscisic acid
(d) cytokinin
Answer: C
Solution: Abscisic acid is a plant hormone that plays an important role under stress conditions. It promotes senescence of leaves and causes abscission of flowers and fruits by forming a layer of abscission. This layer disconnects the living tissue of leaf from the other parts.
Question:21
Which of the following statements about transmission of nerve impulse is incorrect?
(a) Nerve impulse travels from dendritic end towards axonal end
(b) At the dendritic end electrical impulses bring about the release of some chemicals which generate an electrical impulse at the axonal end of another neuron
(c) The chemicals released from the axonal end of one neuron cross the synapse and generate a similar electrical impulse in a dendrite of another neuron
(d) A neuron transmits electrical impulses not only to another neuron but also to muscle and gland cells
Answer: C
Solution: Sensory neurons carry the nerve impulses generated at the sensory receptor towards the CNS. The nerve impulse is transmitted through the axon of one neuron to the dendrite of another neuron. At the end of the axon, neurotransmitters are released which flow through the synapse to the dendrite of another neuron.
Question:22
Involuntary actions in the body are controlled by
(a) medulla in fore brain
(b) medulla in mid brain
(c) medulla in hind brain
(d) medulla in spinal cord
Answer: C
Solution: The medulla oblongata is located in the hindbrain. It is a cone-shaped structure that forms the lower part of the brain stem and connects the brain to the spinal cord. It performs various functions of the autonomous nervous system (ANS) like:
- heart rate,
- breathing,
- swallowing,
- sneezing and
- digestion
by the sympathetic and parasympathetic response.
Question:23
Which of the following is not an involuntary action?
(a) Vomiting
(b) Salivation
(c) Heart beat
(d) Chewing
Answer: D
Solution: Involuntary actions are not under the control of a person’s will. Vomiting, salivation and heart beat are controlled by the autonomous nervous system and are therefore involuntary in nature. While chewing is a voluntary action that a person performs according to his/ her will and involves skeletal muscles which are voluntary.
Question:24
When a person is suffering from severe cold, he or she cannot
(a) differentiate the taste of an apple from that of an ice cream
(b) differentiate the smell of a perfume from that of an agarbatti
(c) differentiate red light from green light
(d) differentiate a hot object from a cold object
Answer: B
Solution: Common cold is a respiratory disease that involves the clogging of the nose with phlegm. It results in the blockage of the perception of smell. The olfactory receptors fail to send the olfactory signals to the nose as a result of which a person won't be able to differentiate between the smell of agarbatti and perfume.
Question:25
What is the correct direction of flow of electrical impulses?
Answer: C
Solution: For the generation of nerve impulses, nerve cells should be in contact with each other. The nerve impulse is transmitted in the following sequence:
Axon end- synapse- dendrites- dendron- cyton- axon body- axon end.
The nerve impulse travels in the form of electrical signals from one end of the axon to the synapse. At the synaptic cleft, the electrical impulse is converted to the chemical impulse. Further, this nerve impulse flows from the synaptic cleft to dendritic tips, converting the chemical impulse to electrical impulse. Thus, the flow of impulse is always from one axonal end of a neuron to dendronal end of another neuron.
Question:26
Which statement is not true about thyroxin?
(a) Iron is essential for the synthesis of thyroxin
(b) It regulates carbohydrates, protein and fat metabolism in the body
(c) Thyroid gland requires iodine to synthesise thyroxin
(d) Thyroxin is also called thyroid hormone
Answer: A
Solution: Thyroid gland produces a hormone called thyroxine into the bloodstream. It regulates the rate of metabolism in the body. Iodine is necessary for the production of thyroid hormones- T3 and T4.
Question:27
Dwarfism results due to
(a) Excess secretion of thyroxin
(b) Less secretion of growth hormone
(c) Less secretion of adrenaline
(d) Excess secretion of growth hormone
Answer: B
Solution: The pituitary gland releases growth hormone (GH) also called as somatostatin. The over-secretion of GH stimulates abnormal growth of the body leading to gigantism and low secretion of GH results in stunted growth resulting in dwarfism. The symptoms of dwarfism include shortened arms and legs, a short neck, broad, rounded chest, slightly flattened cheekbones, slow growth pattern and unusually small stature.
Question:28
Dramatic changes of body features associated with puberty are mainly because of secretion of
(a) oestrogen from testes and testosterone from ovary
(b) estrogen from adrenal gland and testosterone from pituitary gland
(c) testosterone from testes and estrogen from ovary
(d) testosterone from thyroid gland and estrogen from pituitary gland
Answer: C
Solution: Puberty leads to dramatic physical and mental changes in the body of a person. It is the transition stage towards attaining sexual maturity. Sex hormones play a key role here.
In humans, testosterone is the male hormone produced by testes that promotes the development of secondary sexual characteristics. While Oestrogen produced by the ovaries in the females is responsible for the development of secondary sexual characters in females.
Question:29
A doctor advised a person to take an injection of insulin because
(a) his blood pressure was low
(b) his heart was beating slowly
(c) he was suffering from goitre
(d) his sugar level in blood was high
Answer: D
Solution: The specialised cells called as beta cells in Islets of Langerhans in the pancreas produce insulin. It plays a key role in absorption of blood sugar by the cells. Thus, the patient who is advised to take insulin injections might be suffering from high blood sugar level in the body.
Question:30
The hormone which increases the fertility in males is called
(a) oestrogen
(b) testosterone
(c) insulin
(d) growth hormone
Answer: B
Solution: Testosterone is the male sex hormone produces in testes of males which promotes maleness. It helps in promoting spermatogenesis, the process of production of sperm. It also promotes secondary sexual characteristics in case of males.
Question:31
Which of the following endocrine glands is unpaired?
(a) Adrenal
(b) Testes
(c) Pituitary
(d) Ovary
Answer: C
Solution: Except pituitary, all endocrine glands given here are paired in nature.
Adrenal glands are paired present on the top of each kidney. Testes is a paired gland in males which produces male sex hormones. Ovary is a paired gland in females, which produces female sex hormones. Pituitary gland is unpaired and present below the brain. It is also called as master gland as it secretes number of hormones.
Question:32
Junction between two neurons is called
(a) cell junction
(b) neuro muscular junction
(c) neural joint
(d) synapse
Answer: D
Solution: In the nervous system, a synapse is a junction between two neurons where there is a small gap that allows a neuron to pass an electrical or chemical signal to another neuron.
Cell junction provides contact between neighbouring cells. The neuromuscular junction is a synapse between the axon terminals of a motor neuron and a muscle fibre while the neural joint is present in the nervous system.
Question:33
In humans, the life processes are controlled and regulated by
(a) reproductive and endocrine systems
(b) respiratory and nervous systems
(c) endocrine and digestive systems
(d) nervous and endocrine systems
Answer: D
Solution: Reproductive, respiratory and digestive systems have no role to play in control and regulation of the life processes. It is the nervous system and the endocrine system that control and regulates all the processes including reproductive, respiratory and digestive systems.
Nervous system consists of a network of neurons that allows signals to move between the brain and body. The endocrine system releases hormones into the body that regulates a variety of functions such as metabolism, digestion, blood pressure and growth. The endocrine system is not directly linked to the nervous system. They two interact in different ways.
NCERT Exemplar Class 10 Science Solutions Chapter 7-Short Answer
Question:34
Label the parts (a), (b), (c) and (d) and show the direction of flow of electrical signals in Figure 7.2.
Answer:
(a) Sensory neuron- It receives the signals (heat) from the stimulus (hot pan) and carries it directly to the spinal cord.
(b) Spinal cord (CNS)- It is a cylindrical structure that carries bundles of nerve fibres. It receives the signal from the sensory neurons and processes and sends them back through the motor neurons.
(c) Motor neuron- It transmits the signals to the effector muscle (muscle in arm) so that the muscle can take action immediately.
(d) Effector (Muscle in arm)- They act in response to the stimuli and shows contraction.
Question:35
Name the plant hormones responsible for the following
(a) elongation of cells
(b) growth of stem
(c) promotion of cell division
(d) falling of senescent leaves.
Answer:
(a) Auxin helps in the elongation of cells
(b) Gibberlin help in the growth of stem
(c) Cytokinin help in promotion of cell division
(d) Abscisic acid leads to falling of senescent leaves.
Question:36
Label the endocrine glands in Figure 7.3.
Answer:
a) Pineal Gland- It is located in the brain and produces a hormone called as melatonin.
b) Pituitary gland- It is called as the master gland because it controls the secretions of other glands and releases various hormones like growth hormone.
c) Thyroid gland- It secretes hormone thyroxine which helps in regulating the metabolism of the body.
d) Thymus- It produces a hormone thymosin which stimulates the development of T-cells.
Question:38
Label the parts of a neuron in Figure 7.5.
Answer:
a) Dendrite- These are the branch like structures that receives messages from other neurons and help in the transmission of impulses to the cell body.
b) Cellbody-It is also called as soma. It is a star shaped structure with a nucleus, golgi body, endoplasmic reticulum, mitochindria etc.
c) Axon- It is a tube-like structure that carries electrical impulse from the cell body to the axon terminals that passes the impulse to another neuron.
d) Axon terminal- It is the end of an axon that helps in the tranmission of electrical impulse to the dendrites of another neuron.
Question:39
Match the terms of Column (A) with those of Column (B)Column (A) Column (B)
(a) Olfactory receptors (i) Tongue
(b) Thermo receptors (temperature receptors) (ii) Eye
(c) Gustatoreceptors (iii) Nose
(d) Photoreceptors (iv) Skin
Answer: (a)- 3. (b)-4, (c)-1, (d)-2
Sensory receptors are nerve receptors present in different organs of a body and respond to stimulus. Olfactory receptors, thermoreceptors, gustatory receptors, photoreceptors are different sensory receptors. Olfactory receptors present in the nose helps to recognise different types of smell. Thermoreceptors are non-specialised sensory neurons which connect the skin to the hypothalamic region of the brain and detects temperature change. Gustatory receptors also called taste receptors are present in the tongue and detects taste. Photoreceptors are present in eyes. There are two types of photoreceptors, i.e, rods and cones. They contain coloured pigments which help to differentiate between colours.
Question:40
What is a tropic movement? Explain with an example.
Answer:
Tropic movement is the directional growth of the plant in response to the external stimulus present in the environment, this movement is in response to root and shoot growth. Movement can be either toward the stimulus or away from the stimulus. They are mainly of five types:
Phototropism,
- Geotropism,
- Chemotropism,
- Hydrotropism and
- Thigmotropism
Ex: Roots shows positive geotropic movement as they grow downwards the gravity whereas shoots show negative geotropic movement.
Question:41
What will happen if intake of iodine in our diet is low?
Answer:
Iodine is essential for the synthesis of hormone thyroxin. The thyroid gland secretes a hormone thyroxin which controls the rate of metabolism of carbohydrates, fats and proteins in the body. If there is a deficiency of iodine then there will be a deficiency of thyroxine hormone in the body and will cause goitre. The neck appears to be swollen due to enlargement of the thyroid gland which is also called a goitre.
Question:42
What happens at the synapse between two neurons?
Answer:
The transmission of nerve impulses between two neurons takes place through the synapse. The axon terminal of a neuron releases chemical substances called neurotransmitters e.g. acetylcholine. These chemicals travel through the synapse and reach the dendrites of the next neuron. The nerve impulses travel along with the neurotransmitters.
Question:43
Answer the following :
(a) Which hormone is responsible for the changes noticed in females at puberty?
(b) Dwarfism results due to deficiency of which hormone?
(c) Blood sugar level rises due to deficiency of which hormone?
(d) Iodine is necessary for the synthesis of which hormone?
Answer:
(a) Oestrogen hormone is responsible for the changes noticed in females at puberty.
(b) Dwarfism results due to deficiency of growth hormone.
(c) Blood sugar level rises due to deficiency of Insulin hormone.
(d) lodine is necessary for the synthesis of Thyroxine hormone.
Question:44
Answer the following :
(a) Name the endocrine gland associated with brain?
(b) Which gland secretes digestive enzymes as well as hormones?
(c) Name the endocrine gland associated with kidneys?
(d) Which endocrine gland is present in males but not in females?
Answer:
a) Pitutary gland is associated with brain.
b) Pancreas secretes digestive enzymes as well as hormones.
c) Adrenal gland is associated with kidneys.
d) Testis is present in males but not in females.
NCERT Exemplar Class 10 Science Solutions Chapter 7-Long Answer
Question:45
Draw the structure of a neuron and explain its function.
Answer:
Solution:
Neurons are the building blocks of the nervous system. They receive and transmit signals to different parts of the body. There are different types of neurons that help in the transmission of information. Following are the different parts of a neuron:
Dendrites
These are branch-like structures that receive messages from other neurons and allow the transmission of messages to the cell body.
Cell Body
Each neuron has a cell body with a nucleus, Golgi body, endoplasmic reticulum, mitochondria and other components.
Axon
Axon is a tube-like structure that carries electrical impulse from the cell body to the axon terminals that passes the impulse to another neuron.
Mylein sheath acts as an insulator around the axon. It insulates axons from the electrical impulses from the surroundings.
Question:46
What are the major parts of the brain? Mention the functions of different parts.
Answer:
The major parts of the human brain are-
Cerebrum: The cerebrum is the largest part of the human brain. It is divided into two hemispheres; called cerebral hemispheres. The cerebrum controls voluntary motor actions. It is the site of sensory perceptions and the seat of learning and memory.
Hypothalamus: The hypothalamus lies at the base of the cerebrum. It controls sleep and wake cycle of the body. It also controls the urge for eating and drinking.
Cerebellum: Cerebellum lies below the cerebrum and at the back of the whole structure. It is responsible for the voluntary actions of the body and helps in maintaining the equilibrium of the body
Medulla: Medulla forms the brain stem; along with the pons. It lies at the base of the brain and continues into the spinal cord. The medulla controls various involuntary functions: like a heartbeat, respiration, etc.
Question:47
What constitutes the central and peripheral nervous systems? How are the components of central nervous system protected?
Answer:
The central nervous system consists of brain and the spinal cord. The peripheral nervous system consists of all the nerves in the body that lies outside of the spinal cord and brain.
The central nervous system has a well-developed system for its protection. Brain is enclosed in a hard shell know as skull. Spinal cord is enclosed in vertebral column for its protection. Along with these there is cerebrospinal fluid which protects the brain from mechanical shocks.
Question:48
Mention one function for each of these hormones :
(a) Thyroxin
(b) Insulin
(c) Adrenaline
(d) Growth hormone
(e) Testosterone.
Answer:
(a) Thyroxin regulates carbohydrate, protein and fat matabolism in the body so as to provide the best balance for growth.
(b) Insulin regulates blood sugar levels in the body.
(c) Adrenaline increases heart rate and supply of blood to various organs.
(d) Growth hormone regulates growth and development in the body.
(e) Testosterone controls the changes of body features associated with puberty in male.
Question:50
What are reflex actions? Give two examples. Explain a reflex arc.
Answer:
The sudden involuntary movement in a voluntary organ; in response to a stimulus; is called reflex action.
Examples of reflex action:
- (a) Moving your hand away from a hot pan.
- (b) Blinking of eyes
Reflex Arc: Reflex arc is a path of electrical impulse during a reflex action. It is composed of sensory neuron, spinal cord, motor neuron and
muscle.
Steps of reflex arc
• The sensory neuron picks signals from the stimulus and carries the signals to the spinal cord.
• Spinal cord process the signals and sends the message through the motor neuron.
• Motor neuron transmits the signals to the effector's muscle so that the muscle can take immediate action
Question:51
“Nervous and hormonal systems together perform the function of control and coordination in human beings.” Justify the statement.
Answer:
The control and coordination in human beings is because of nervous and endocrine system. These two systems work in different ways. Brain controls all the functions of the body with the help of network of neurons which carry signals through neurotransmitters in the form of electric impulses to the brain and from the brain. The hormonal system consists of hormones secreted by various glands in our body.
Hormonal system coordinates the function of nervous system. Hormones indirectly control the life processes by feedback mechanism. They can produce hormones when required and can stop production when not required.
Question:52
How does chemical coordination take place in animals?
Answer:
The chemical coordination in animals take place through hormones produced by the ductless glands i.e. endocrine glands of the body. Hormones are directly released into blood stream to reach the target site. Hormones control the behavior of the target tissue.
Example: Adrenaline hormone is secreted by the adrenal gland which reaches the heart, lungs and gastro intestinal tract. Heart speeds up its pumping action so that more blood could be supplied to the limbs and facial muscles. But activity of the GI tract is slowed down to ensure better blood supply in limbs. Thus, adrenalin prepares the body for a fight or flight situation
These NCERT exemplar Class 10 Science chapter 7 solutions form a more solid understanding of control and coordination because of their comprehensive nature. The CBSE Syllabus for Class 10 chapter 7 is incorporated in the NCERT exemplar Class 10 Science chapter 7 solutions.
NCERT Exemplar Solutions Class 10 Science Chapter 7 Important Topics:
NCERT exemplar Class 10 Science solutions chapter 7 explores the key topics mentioned below:
- How the coordination and control work.
- NCERT exemplar Class 10 Science solutions chapter 7 discusses the nervous system and how an electric impulse travels in neurons.
- In this chapter, we will learn about receptor cells which gives a sense of taste or smell
- Different behaviors of movement of different kinds of plants such as the growth of sunflower towards the sun.
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Features of NCERT Exemplar Class 10 Science Solutions Chapter 7:
These Class 10 Science NCERT exemplar chapter 7 solutions discuss the control and coordination in living organisms such as animals and plants.
In order to hone the knowledge required to practice the problems based on Control and Coordination, students are suggested to refer to these solutions.
Class 10 Science NCERT exemplar solutions chapter 7 Control and Coordination will help develop a clear understanding of the concept leading to an effortless sailing through other books such as Biology question bank, S Chand Lakhmir Singh Biology Class 10 and NCERT Class 10 Science.
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