Control and Coordination Class 10 Notes Science Chapter 7

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control and coordination class 10 notes science chapter 7

Control and coordination class 10 notes along with questions and answers and solutions – 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 in plants coordinate the movements.

Receptors

Receptors: specialized tips of the nerve fibres that collect the information to be conducted by the nerves. They are in the sense organs of the animals. These are classified as follows :

  • Phono-receptors: These are present in inner ear.
    Functions: The main functions are hearing and balance of the body.
  • Photo-receptors: These are present in the eye.
    Function: These are responsible for visual stimulus.
  • Thermo-receptors: These are present in skin.
    Functions: These receptors are responsible for pain, touch and heat stimuli (thermoreceptors).
  • Olfactory-receptors: These are present in nose.
    Functions: These receptors receive smell.
  • Gustatory-receptors: These are present in the tongue.
    Functions: These helps in taste detection.

Nervous System

The nervous system is composed of specialized tissues, called nervous tissue. The nerve cell or neuron is the functional unit of the nervous system. It is the nervous system which is mainly responsible for control and coordination in complex animals.

Functions of the nervous system

  • Nervous system receives information from the environment.
  • To receive the information from the various body.
  • To act according to through muscles and glands.

A neuron is the structural and functional unit of the nervous system.

Neuron

Neuron is a highly specialized cell which is responsible for the transmission of nerve impulses. The neuron consists of the following parts
(i) Cyton or cell body: The cell body or cyton is somewhat star-shaped, with many hair like structures protruding out of the margin called dendrites. Dendrites receive the nerve impulses.
(ii) Axon: This is the tail of the neuron. It ends in several hair-like structures, called axon terminals. The axon terminals relay nerve impulses.
(iii) Myelin sheath: There is an insulator cover around the axon called myelin sheath. The myelin sheath insulates the axon against nerve impulse from the surroundings.

Types of neurons

Central nervous system – brain and 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.

Also Learn About : Life Processes

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.
  • The autonomous nervous system is divided into two parts:

Sympathetic Nervous System: This part of the autonomous nervous system heightens the activity of an organ as per the need. For example, during running, there is an increased demand for oxygen by the body. The sympathetic nervous system works to increase the breathing rate the heart rate, in this case.

Parasympathetic Nervous System: This part of the autonomous nervous system slows the down the activity of an organ and thus has a calming effect. During sleep, the breathing rate slows down and so does the heart rate. This is facilitated by the parasympathetic nervous system which helps in the conservation of energy.


Control and Coordination Class 10 Notes Science Chapter 7 3

Human Brain – control and coordination class 10 notes

The tissues are highly folded to accommodate a large surface area in less space. The brain is covered by a three-layered system of membranes, called meninges. The CSF providers cushion the brain against mechanical shocks. Furthermore, protection.

Control and Coordination Class 10 Notes Science Chapter 7 4

Cerebrum: 

The cerebrum is the largest part in the human brains which is divided into cerebral hemispheres.

Functions of cerebrum

  • The cerebrum controls voluntary motor actions.
  • It is the site of sensory perceptions, like tactile and auditory perceptions.
  • It is the seat of learning and memory.

Hypothalamus: 

The hypothalamus lies at the base of the cerebrum. It controls sleep and wake cycle (circadian rhythm) of the body. It also controls the urges for eating and drinking.

Cerebellum: 

Cerebellum lies below the cerebrum and at the back of the whole structure. It coordinates the motor functions. It controls posture and balance and the precision of voluntary action.

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 hear beat respiration, etc.
It controls involuntary actions.
Example: Blood pressure, salivation, vomiting.

Pons:

t relays impulses between the lower cerebellum and spinal cord, and higher parts of the brain like the cerebrum and midbrain, also regulates respiration.

Spinal cord – control and coordination class 10 notes

Spinal cord controls the reflex actions and conducts massages between different parts of the body and brain.

Reflex Action: 

Reflex action is a special case of involuntary movement involuntary organs. When a voluntary organ is in the vicinity of sudden danger, it is immediately pulled away from the danger to save itself. For example, when your hand touches a very hot electric iron, you move away your hand in a jerk. This is an example of reflex action.

Reflex Arc: 

The path through which nerves signals, involved in a reflex action, travel is called the reflex arc. The following flow chart shows the flow of signal in a reflex arc.
Receptor → Sensory neuron → Relay neuron → Motor neuron → Effector (muscle)
The receptor is the organ which comes in the danger zone. The sensory neurons pick signals from the receptor and send them to the relay neuron. The relay neuron is present in the spinal cord. The spinal cord sends signals to the effector via the motor neuron. The effector comes in action, moves the receptor away from the danger.


Control and Coordination Class 10 Notes Science Chapter 7 5

The Endocrine System – control and coordination class 10 notes

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 and 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.
  • 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.
Control and Coordination Class 10 Notes Science Chapter 7 7

Control and coordination class 10 notes – Plant Hormones and Movements

Plant 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

Control and Co-ordination in Plants

Control and Coordination Class 10 Notes Science Chapter 7 10

Unlike animals, plants do not have a nervous system. Plants use chemical means for control and co-ordination. Many plant hormones are responsible for various kinds of movements in plants. Movements in plants can be divided into two main types :

  1. Tropic movement
  2. Nastic movement

1. Tropic Movement – control and coordination class 10 notes

The movements which are in a particular direction in relation to the stimulus are called tropic movements. Tropic movements happen as a result of growth of a plant part in a particular direction. There are four types of tropic movements.


(i) Geotropic movement: 

The growth in a plant part in response to the gravity is called geotropic movement. Roots usually show positive geotropic movement, i.e. they grow in the direction of the gravity. Stems usually show negative geotropic movement.

(ii) Phototropic Movement: 

The growth in a plant part in response to light is called phototropic movement. Stems usually show positive phototropic movement, while roots usually show negative phototropic movement. If a plant is kept in a container in which no sunlight reaches and a hole in the container allows some sunlight; the stem finally grows in the direction of the sunlight. This happens because of a higher rate of cell division in the part of stem which is away from the sunlight. As a result, the stem bends towards the light. The heightened rate of cell division is attained by increased secretion of the plant hormone auxin in the which is away from sunlight.

(iii) Hydrotropic Movement: 

When roots grow in the soil, they usually grow towards the nearest source of water. This shows a positive hydrotropic movement.

(iv) Thigmotropism Movement: 

The growth in a plant part in response to touch is called thigmotropism movement. Such movements are seen in tendrils of climbers. The tendril grows in a way so as it can coil around a support. The differential rate of cell division in different parts of the tendril happens due to action of auxin.

2. Nastic Movement – control and coordination class 10 notes

The movement which do not depend on the direction from the stimulus acts are called nastic movement. For example, when someone touches the leaves of mimosa, the leaves droop. The drooping is independent of the direction from which the leaves are touched. Such movements usually happen because of changing water balance in the cells. When leaves of mimosa are touched, the cells in the leaves lose- water and become flaccid, resulting in drooping of leaves.

Conclusion – control and coordination class 10 notes

Control and coordination class 10 notes along with questions and answers and solutions – In this chapter we learnt about the nervous system and the endocrine system. We also understood the control and coordination in plants and how they are different from humans.

Questions and answers – control and coordination class 10 notes

Questions Page number 119 – control and coordination class 10 notes

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 and 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. Such a connection of detecting the signal from the nerves (input) and responding to it quickly (output) is known as reflex arc.

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 – control and coordination class 10 notes

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

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.

NCERT Solution for Class 10 Science Chapter 7 - image 1

Questions Page number 125 – control and coordination class 10 notes

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 – control and coordination class 10 notes

1. Which of the following is a plant hormone?

(a) Insulin

(b) Thyroxin

(c) Oestrogen

(d) Cytokinin

Solution:

Answer is d) cytokinin.

2. The gap between two neurons is called a

(a) Dendrite.

(b) Synapse.

(c) Axon.

(d) Impulse.

Solution:

Answer is (b) Synapse

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

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.

NCERT Solution for Class 10 Science Chapter 7 - image 2

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. 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. 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 other voluntary and involuntary action are controlled by central nervous system (CNS).

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

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.

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.

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