CBSE Class 10 Science Control And Coordination

This CBSE Class 10 Science chapter 7 notes page on Control and Coordination covers stimulus, the nervous and hormonal systems, the structure of the neuron, the parts of the brain and spinal cord, reflex action, endocrine glands and their hormones, and coordination in plants through tropic movements and plant hormones, along with a question bank.

CHAPTER 7: CONTROL AND COORDINATION

Stimulus:
The change in the environment to which an organism responds and reacts is called stimulus.

Control and Coordination in Animals:
Control and coordination in animals takes place by:
(a) Nervous system
(b) Hormonal system (Endocrine glands)

Parts of Nervous System:
(a) Brain
(b) Spinal cord
(c) Nerves

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

Parts of Neuron:
(a) Dendrites
(b) Cell body
(c) Axon

Synapse:
A synapse is the junction between two adjacent nerves.

Reflex Action:
A reflex action is a spontaneous, involuntary and automatic response to a stimulus, which protects us from harmful situations. For example, on touching a hot object unknowingly, we instantly withdraw our hand.

[Figure: Figure 7.1 (a) Structure of neuron, showing dendrite, cell body, axon and nerve ending. (b) Neuromuscular junction, showing axon, neuromuscular junction, mitochondrion, muscle fibre, capillary]

NERVOUS SYSTEM

Division of Nervous System:
1. Central Nervous System (CNS)
2. Peripheral Nervous System (PNS)
(i) Autonomic Nervous System
(ii) Voluntary Nervous System

Brain:
(i) The brain is the centre of coordination of all activities.
(ii) Thinking is involved in its functions.
(iii) It is a complex process.

Parts of Brain:
Refer to Figure 7.3 on page 118 of the NCERT textbook.

Forebrain (Cerebrum):
(i) The cerebrum is the main thinking part and the largest part of the brain.
(ii) It has three main areas:
a. Sensory area: to receive impulses from sense organs through receptors
b. Motor area: controls voluntary movements
c. Association areas: reasoning, learning and intelligence

Thalamus:
The thalamus relays sensory information to the cerebrum.

Hypothalamus:
The hypothalamus forms the link between the nervous system and the endocrine system.

Mid Brain:
The mid brain connects the forebrain and the hindbrain.

Hindbrain:
The hindbrain consists of the cerebellum, pons and medulla oblongata.

Cerebellum:
The cerebellum controls and coordinates muscular movements, and maintains body posture and equilibrium.

Pons:
The pons acts as a bridge between the brain and the spinal cord.

Medulla Oblongata:
The medulla oblongata controls involuntary actions such as blood pressure, salivation and vomiting.

Spinal Cord:
The spinal cord is a cylindrical or tubular structure extending downwards from the medulla oblongata.

Protection of the Brain and the Spinal Cord:
(i) Bony outer covering: the skull for the brain and the vertebral column for the spinal cord.
(ii) Cerebrospinal fluid, present between the three membranes.

[Figure: Mind map titled Human Nervous System. Central Nervous System has Brain (Forebrain, Mid brain, Hindbrain) and Spinal Cord. Peripheral Nervous System has Cranial nerves and Spinal nerves, Somatic nervous system, and Autonomic nervous system, which is divided into Sympathetic and Parasympathetic. Visceral nervous system is also listed under Peripheral Nervous System]

Reflex Arc:
The path of a reflex action is called the reflex arc. Its components are the receptors (heat or pain receptors in the skin), the sensory neuron, the relay neuron in the spinal cord (CNS), the motor neuron, and the effector muscle. The message also reaches the brain.

[Figure: Reflex arc. Heat or pain receptors in the skin send the stimulus along the sensory neuron to the spinal cord (CNS). A relay neuron in the spinal cord passes the impulse to the motor neuron, which carries the response to the muscle. A message also goes to the brain. The example shows a hand withdrawing from a hot vessel]

HORMONES

Hormones:
(i) Hormones are chemical messengers secreted by endocrine glands.
(ii) They are secreted in small amounts and may act in nearby places or distant places.
(iii) They do not take part in the reaction and are destroyed immediately.

Important Endocrine Glands, the Hormones They Secrete and Their Functions:
Refer to Figure 7.7 on page 124 of the NCERT textbook.

[Figure: Figure 7.7 Endocrine glands in human beings: (a) male, showing Pineal gland, Hypothalamus, Pituitary gland, Thyroid gland, Parathyroid glands, Thymus, Pancreas, Adrenal glands and Testis. (b) female, showing the same glands with Ovary in place of Testis]

COORDINATION IN PLANTS

Only chemical coordination is present in plants.

Tropic Movements:
The movements of plants in the direction of a stimulus (positive) or away from it (negative) are called tropic movements. Examples are phototropism, geotropism and chemotropism.
Refer to Figures 7.4 and 7.5 on page 121 of the NCERT textbook.

Plant Hormones (Phytohormones):
Plant hormones are chemical messengers that control growth and responses in plants.

QUESTION BANK

VERY SHORT ANSWER TYPE QUESTIONS

1. Name the hormone which helps in regulating sugar level in our blood? Name the gland which secretes this hormone?
2. State the main function of abscisic acid.
3. Write name of three hormones secreted by the pituitary gland.
4. Mention one example of chemotropism.

SHORT ANSWER TYPE QUESTIONS (2 MARKS)

1. Name the following:
(a) Necessary for thyroid glands
(b) Necessary to maintain sugar level of the body

2. Draw the diagram of a nerve cell and label the following on it: (a) Nucleus (b) Dendrites

3. How does our body maintain blood sugar level?

SHORT ANSWER QUESTIONS (3 MARKS)

1. A compound of iodine is compulsorily added to common salt in small quantity.
(a) Why is it important for us to have iodised salt in our diet?
(b) Name the disease caused by its deficiency.
(c) Write the symptoms of the disease.

2. What is reflex action? Describe the steps involved in reflex action.

3. Name the following:
Response of plants to light, chemical and water.

VALUE BASED QUESTION

Ritesh is fond of eating pickles. As he hears the name of pickles, watering starts in his mouth. His friends used to make fun of him. When the same process or event was executed to the dog of Ritesh, the result was different. Now answer the following questions:
(i) What is the biological term for the watering of Ritesh in his mouth?
(ii) Why did the dog of Ritesh not water from mouth in the same events?
(iii) What is the value shown by his friends?

LONG ANSWER QUESTIONS (5 MARKS)

1. Name the plant growth hormone which is synthesized at the shoot tip. Explain briefly why a plant bends towards light during its growth.
2. Draw the diagram of human brain and label the parts. Write the function of cerebellum and pons.
3. What is reflex action? Describe the steps involved in reflex action.
4. Name the following:
Response of plants to light, chemical and water.

Hypothalamus- It forms the link between Nervous system & Endocrine system

Mid brain- It connects fore brain and hind brain

Hind Brain- connects the fore brain and hind brain

Question. Which of the following is not a plant harmone?
(A) Auxin
(B) Gibberellins
(C) Cytokinin
(D) Adrenaline
Answer : D

Question. Choose the right option from the following.
i. In light, hormone auxin, helps the cells to grow longer in plants.
ii. Plant hormone gibberellins helps in growth of a stem.
iii. Cytokininis inhibits cell division.
iv. Abscisic acid promote growth in plants.
(A) i and iii are correct
(B) ii and iv are correct
(C) i and ii are correct
(D) i and iv are correct
Answer : C

Question. The two hormones secreted by adrenal glands which regulates the concentration of salts in blood and prepares the body to face the emergency are .................and ..................
(A) Insulin and Glucagon
(B) Testosterone and Estrogen
(C) Cortisone and Dopamine
(D) Cortitisone and Adrenaline
Answer : D

Question. The essential hormome for ripening of fruits is :
(A) Auxin
(B) Cytokinin
(C) Ethylene
(D) Gibberellin
Answer : C

Question. Cut leaves remain green for longer time if dipped in :
(A) Auxins
(B) Cytokinins
(C) Ethylene
(D) Gibberellins
Answer : B

Question. Neurons have a unique property that makes them to communicate with other cells via :
(A) Nerve cords
(B) Glial cells
(C) Synapses
(D) Schwann cells
Answer : C

Question. Which one is anti transpirant hormones ?
(A) Auxin
(B) Cytokinin
(C) Abscisic Acid
(D) Gibberellin
Answer : C

Question. Which one of the following is secreted by pituitary gland?
(A) Insulin
(B) Estrogen
(C) Adrenaline
(D) Growth hormone
Answer : D

Question. One of the basic characteristics of living organisms which is well developed in nervous system is :
(A) Movement
(B) Growth
(C) Irritability
(D) Nutrition
Answer : C

Question. If a person cannot walk in a straight line or cannot balance a ride on bicycle, probably which part of his brain is not working properly ?
(A) Cerebrum
(B) Cranium
(C) Cerebellum
(D) Hypothalamus
Answer : C

Question. Lack of melanin synthesis may cause the genetic disorder.
(A) Colour blindness
(B) Haemophilia
(C) Albinism
(D) Hypertrichosis
Answer : C

Question. Hormone which stimulate initiation of flowering process is :
(A) Gibberellin
(B) Ethylene
(C) Vernalin
(D) Florigen
Answer : D

Question. Choose the corret alternate in which the type of tropism exhibited by plants is correctly matched with the stimulus to which they respond
    Tropism                      Stimulus
1) Hydrotropsin           i) Earth
2) Geotropism             ii) Light
3) Chemotropism       iii) Water
4) Phototropism         iv) Chemical
(A) 1 – ii, 2 – i, 3 – iv, 4 – iii
(B) 1 – iii, 2 – i, 3 – iv, 4 – ii
(C) 1 – iv, 2 – iii, 3 – i , 4 – ii
(D) 1 – iii, 2 – i , 3 – ii, 4 – iv
Answer : B

Question. Which two of the following are growth promoting hormones in plant ?
(A) Auxin and Cytokinin
(B) Gibberelin and Ethylene
(C) Abscisic acid and Auxin
(D) Cytokinin and Ethylene
Answer : A

Question. Which part of the brain controls co-ordinated movements of our body, such as riding a bicycle ?
(A) Cerebrum
(B) Cerebellum
(C) Medulla
(D) Pons
Answer : B

Question. The functional junction between two neurons is called
(A) synapse
(B) axon
(C) dendrites
(D) none of these
Answer : A

Question. The correct order of the parts of a nerve cell through which a nerve impulse is transmitted is.
(A) Nerve endings-dendrites-axon-cell body
(B) Cell body-axon-dendrites -nerve endings
(C) Dendrites-nerve endings-cell body axon
(D) Dendrites - cell body-axon-nerve endings
Answer : D

Question. Which is the largest endocrine gland in human beings.
(A) Pituitary
(B) Adrenal
(C) Thyroid
(D) Parathyroid
Answer : C

Question. Which of the following ion is needed for nerve conduction?
(A) Ca
(B) Zn
(C) Mg
(D) Na
Answer : D

Question. When we smell a flower, which one of the following first receives the scent?
(A) Dendrite of motor neur on
(B) Dendrite of sensory neuron
(C) Axon of motor neuron
(D) Axon of sensory neuron
Answer : B

Question. Show the pathway of electric impulse :
(A) Dendrite → Cell body → Axon → to its end
(B) Cell body → Dendrite → Axon → to its end
(C) Axon → Cell body → Dendrite → to. its end
(D) Dendrite → Axon → Cell body → to its end
Answer : A

Question. The systematic regulation of various activities means :
(A) Control
(B) Co-ordiantion
(C) Taming
(D) Randomness
Answer : B

Question. Which is the hormone that brings about changes in girls during puberty?
(A) Estrogen
(B) Progesterone
(C) Testosterone
(D) Thyroxine
Answer : A

Question. If the apical parts of the negative geotropic roots of mangrove plant are pasted with wax, which function of these roots will be affected ?
(A) Exchange of O₂ and CO₂
(B) Water absorption
(C) Fixation of plant
(D) Photosynthesis
Answer : A

Question. In plants abscisic acid controls
(A) growth in shoot
(B) flower formation
(C) cell division
(D) fall of leaf
Answer : D