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Class 10th Chapter 7 Control and Coordination Notes for Exam

Class 10 Science Notes Chapter 7 Control and Coordination

 The human body is a complex machine performing tons of functions and processes to maintain and sustain life. Explore how the body controls its movements and coordinates its actions with other parts of the body and the environment by exploring notes for Class 10 Chapter 7 Control and Coordination.

The Nervous System

Movement in organisms

The ability of organisms to move certain body parts is movement.

When they move from one place to another, it is called locomotion.

Organisms show movements in response to stimuli.

Introduction to control & coordination

  • Organisms move in response to various kinds of stimuli like light, heat, nutrients/food, etc.
  • All the activities in animals are controlled and coordinated by the nervous and endocrine system.
  • Hormones are chemical messengers, which assist the nervous system in carrying out various functions. They are secreted by endocrine glands.
  • Hormones in plants coordinate the movements.

THE NERVOUS SYSTEM

Neuron

Neuron is the structural and functional unit of the nervous system.

  • Each neuron has three main parts: dendrites, cyton/soma/cell body and axon.
  • Dendrites receive impulses from other neurons.
  • Cyton/soma processes the impulse.
  • Axon transmits the impulse, either to another neuron or to muscles/glands, etc.
  • Axon may be myelinated or non-myelinated.
  • The impulse transmission is faster in myelinated neurons.
Chapter7 Control and Coordination

Central nervous system

The central nervous system (CNS) is made up of the brain and the spinal cord. Functions of different parts of the brain are:

  • Cerebrum is responsible for reasoning, logic, emotions, speech, memory, visual processing, recognition of auditory and taste stimuli, etc.
  • Cerebellum regulates and coordinates body movements, posture and balance.
  • Pons relays signals from hindbrain to forebrain.
  • Medulla Oblongata controls all involuntary movements like vomiting, sneezing, yawning, heartbeat, breathing, blood pressure, etc.
  • Medulla oblongata continues as the spinal cord which runs through the vertebral column and it controls reflex actions.
Chapter7 Control and Coordination

Peripheral nervous system

  • The nerves given out by the brain and the spinal cord form the peripheral nervous system (PNS).
  • There are 12 cranial nerves and 31 spinal nerves in humans.

Somatic nervous system

  • It forms a part of the PNS.
  • The nerves of PNS that control the voluntary actions of the body form the somatic nervous system.

Autonomic nervous system

  • All the nerves of the PNS that control the involuntary actions in the body form the autonomic nervous system.
  • Two divisions of autonomic nervous system are: sympathetic and parasympathetic nervous system.
  • The sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response, while the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.

Reflex action

Reflex action is a sudden, involuntary reaction of the body in response to stimuli.

Reflex arc

  • It is the path followed by electrical impulse during a reflex action.
  • The impulse travels from the receptor organ to the spinal cord/brain. It is processed there and the information is brought back to the concerned muscle to carry out the action.
  • Thus, receptor organ, sensory/afferent neuron, interneuron, motor/efferent neuron and effector organ are the components of a reflex arc.
Chapter7 Control and Coordination

Protection of CNS

The brain is protected by 3 main layers –

  • The bony skull (cranium)
  • The cerebrospinal fluid
  • The meninges (Dura mater, Arachnoid and Pia mater).

Plant Hormones and Movements

Plant hormones

Control and coordination in plants are carried out by hormones.

Plant Hormone  Function
AuxinHelps in Growth of Plant Tissue
CytokininPromotes Cell division, delays aging of cells
GibberilinsHelps in growth of stems, initiates seed germination, promotes flowering, cell division and seed growth after germination
Abscisic acidInhibits growth and causes wilting of leaves, promotes dormancy of buds and seeds
EthyleneThis is a gaseous hormone which causes ripening of fruits
Chapter7 Control and Coordination

Growth independent movements

The movements which are not growth related are called nastic movements. These movements occur in response to environmental stimuli but the direction of response is not dependent on the direction of the stimulus.

  • The movement in the touch-me-not plant is thigmonastic movement (movement in response to touch).

Growth-related movements in plants

The movements which are growth related are called tropic movements. These movements occur in response to environmental stimuli and the direction of the response is dependent on the direction of the stimulus.

Examples:

  • Phototropic movement (light dependent)
  • Geotropic movement (gravity dependent)
  • Chemotropic movement (chemical dependent)
  • Hydrotropic movement (water dependent)
  • Thigmotropic movement (touch dependent)

Geotropism

Movement of plant parts in response to earth’s gravitational force is known as geotropism/gravitropism.

  • Towards gravity – positive geotropism
  • Away from gravity – negative geotropism
  • Root grows towards gravity and shoot grows away from gravity

Phototropism

Movement of plant parts in response to light is known as phototropism.

  • Towards light – positive phototropism
  • Away from light – negative phototropism
  • Stems move towards light and roots move away from light

Hydrotropism

Movement of plant parts in response to water or moisture.

  • Towards water – positive hydrotropism
  • Away from water – negative hydrotropism
  • Again, root movement in search of water is positive hydrotropism

Chemotropism

Movement of plant parts in response to chemical stimuli is known as chemotropism.

  • Towards chemical – positive chemotropism
  • Away from chemical – negative chemotropism
  • The growth of pollen tube towards the ovule is positive chemotropism

Thigmotropism

Movement of plant parts in response to touch is called as thigmotropism.

  • Towards touch – Positive thigmotropism
  • Away from touch – negative thigmotropism
  • Movement of tendrils around the support is positive thigmotropism

The Endocrine System

Exocrine glands

Exocrine glands are glands that discharge secretions by means of  ducts, which open onto an epithelial surface.

Endocrine glands

Endocrine glands are the ductless glands which secrete hormones into the bloodstream in humans.

Pituitary gland

  • It is a pea-sized gland located at the base of the brain.
  • It is the master gland as it controls the secretions of all the other endocrine glands.
  • It also secretes Growth Hormone (GH). Under-secretion of GH causes ‘Dwarfism’ and over-secretion causes ‘Gigantism’ in children and ‘Acromegaly’ in adults.

Thyroid gland

  • It is a butterfly-shaped gland located in the throat.
  • It secretes the hormone ‘Thyroxine’ which regulates the metabolism of the body.
  • Iodine is required to synthesize thyroxine in the body.
  • In case of iodine deficiency, under-secretion of thyroxine leads to goitre.

Pancreas

  • It is a leaf-like gland present behind the stomach in the abdomen.
  • It is an endocrine as well an exocrine gland.
  • As an endocrine gland, it manufactures two hormones – Insulin and glucagon. Both these hormones act antagonistically and regulate the sugar level in the blood.
  • As an exocrine gland, it secretes enzymes to break down the proteins, lipids, carbohydrates and nucleic acids in food.
  • Insufficient amount of insulin from pancreas leads to diabetes.

Adrenal gland

  • Occurs in pair above each kidney.
  • It decreases in size with age.
  • Secrets the hormone adrenaline which helps in flight and fight response.
  • Also secretes nor adrenaline

Gonads

  • Gonads are the gamete-producing organs – testes in males and ovaries in females.
  • The testes produce the male hormone testosterone and ovaries produce the female hormones oestrogen and progesterone.
  • Testosterone and oestrogen help in producing gametes and are responsible for the sexual characteristics in males and females respectively.
  • Progesterone is the pregnancy hormone.

Other endocrine organs

  • The other endocrine organs include the hypothalamus, parathyroid, pineal and thymus glands.

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 Hind 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 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. noMovement of leaves of the sensitive plantMovement of a shoot towards light
1It does not depend on the direction of stimulus applied.Depends on the direction of stimulus applied.
2Called as Nastic movementCalled as tropic movement
3Touch is the stimulusLight is the stimulus
4Caused by the sudden loss of water from the swellings at the base of leavesCaused by the unequal growth on the two sides of the shoot.
5Not a growth movementGrowth movement
6Occurs very fastOccurs slowly
Chapter7 Control and Coordination

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.

Chapter7 Control and Coordination

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 hormone is secreted in large amounts when a person is frightened, or mentally disturbed. When it reaches the heart, it beats faster to supply more oxygen to our muscles. The breathing rate also increases because of the contractions of diaphragm and the rib muscles. It also raises the blood pressure, and allows more glucose to enter into the blood. All these responses together enable our body to deal with the emergency situations.

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.

Chapter7 Control and Coordination

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 Reflex action – Impulses from various body parts will not be conducted to brain. Message from brain will not be conducted to various organs of the body.

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 have need of control and coordination system in an organisms.

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

Solution:

Reflex actionsInvoluntary actions
1. Rapid automatic responses to a stimulus without the conscious involvement of the brain1. Occurs without the consciousness of an organism
2. Controlled by spinal cord2. Controlled by mid brain or medulla oblongata
3. Very quick and instantaneous3. Relatively slower
4. May involve any muscle or a gland4. Involves only smooth muscles
5. Can be conditioned5. Cannot be influenced by external conditioning
Examples: Blinking of eyes, salivationExamples: Beating of heart, blood circulation
Chapter7 Control and Coordination

11. Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.

Solution:

Nervous controlHormonal Control
1It is consist of nerve impulses between PNS, CNS and Brain.1It consists of endocrine system which secretes hormones directly into blood.
2Here response time is very short.2Here response time is very long.
3Nerve impulses are not specific in their action.3Each hormone has specific actions.
4The flow of information is rapid.4The flow of information is very slow.
Chapter7 Control and Coordination

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. noMovement in sensitive plantsMovement in our legs
1The movement in a sensitive plant is a response to stimulus (touch) which is an involuntary action.1Movement in our legs is a voluntary action.
2No special tissue is there for the transfer of information2A complete system CNS and PNS is there for the information exchange.
3Plant cells do not have specialized protein for movements.3Animal cells have specialized protein which help muscles to contract.
Chapter7 Control and Coordination

Frequently Asked Questions on Control and Coordination

What happens at the synapse between two neurons?

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 an electrical signal.

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

Cerebellum which is a part of Hind brain is responsible for Controls the motor functioning hence it is the part reengaged in the maintenance of posture and equilibrium of the body.

How do we detect the smell of an agarbatti (incense stick)?

The smell of an agarbatti is detected by Nose, olfactory receptors present in the nose sends an electrical signal to the fore brain. Fore brain interprets this signal as the incense stick to be detected as smell.

What are plant hormones?

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.

How does chemical coordination take place in animals?

Chemical coordination takes place in animals with the help of chemical messengers called 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.

Why is the use of iodised salt advisable?

Usage of Iodised 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.

Download Notes & NCERT Solutions(click here)

chapter7-control-coordination

Category: Class 10th

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