* Coordination-The working together of various organs of the body of an organism in a proper manner to produce appropriate reaction to a stimulus is called coordination.

*  Stimulus- The changes in the environment to which an organism responds and reacts is called Stimulus

*  Control & coordination in animals- takes place by (i) Nervous system & (ii) Endocrine system

*  Nervous system

Stimulus →  Receptor organ →  Sensory nerve  → Brain/Spinal cord

Response  ← Effector organ   ←    Motor nerve

*   Endocrine system

Stimulus →  Endocrine organ →  Secrete hormone  → Hormone in blood

Response  ←    Target organ

*  Parts of the Nervous system – (i)  Brain  (ii) Spinal cord  (iii) Nerves (Neurons)

*  A Neuron is the structural & functional unit of Nervous system

*  Parts of a neuron- (i)  Dendrites  (ii)  Cell body  (iii) Axon

*  Synapse- Space/junction between two adjacent nerves is called Synapse.

*  Passing of information takes place –(i) By Electric impulse (inside the neuron) and                                   (ii) In the form of chemicals (At synapse)

* Reflex action- Spontaneous, involuntary and automatic response to a stimulus to protect us from harmful situations. Eg. On touching a hot object unknowingly we instantly withdraw our hand.

*  Reflex arc- The pathway of the reflex action is called Reflex arc.

Stimulus → Receptor organ →  Sensory nerve  → Spinal cord →→Effector organ→  Response Refer to figure 7.2 page no. 117 of N.C.E.R.T  Text book)

*  Nervous system- (1)  Central Nervous system (CNS)           (2) Peripheral Nervous system (PNS)

(i)  Brain                            (i)  Autonomic Nervous system

(ii)  Spinal cord              (ii)  Voluntary Nervous system

*  Brain  (i)  Centre of coordination of all activities (ii)  Thinking is involved (iii) Complex process

*  Parts of brain-       Refer to figure 7.3 page no. 118 of N.C.E.R.T  Text book

    Fore brain                  Mid brain Hind brain
                                       (i) Cerebrum(ii)  Thalamus                                                                                                     (iii)  Hypothallamus ———-                                                                                                          (i) Cerebellum                                                                                                          (ii) Pons                                                       (iii)  Medulla oblongata


*  Fore brain Cerebrum- (i)  Main thinking and largest part of the brain.

(ii)  It has 3 main areas-

  1. Sensory area- to receive impulses from sense organs via Receptors
  2. Motor area- control voluntary movements.
  3. Association areas- Reasoning, learning & intelligence.

Thalamus – It relays sensory information to the Cerebrum Hypothallamus- It forms the link between Nervous system & Endocrine system

*  Mid brain- It connects Fore brain and Hind brain. Controls reflex of eyes & ears

*  Hind brain- Connects the Fore brain & Hind brain  Cerebellum – Controls & coordinates muscular movements, maintaining body posture and equilibrium.

Pons- Acts as a bridge between brain & spinal cord Medulla oblongata- Controls involuntary actions like blood pressure, salivation, vomiting, etc.

*  Spinal cord- Cylindrical or tubular structure extending downwards from the Medulla oblongata.

*  Protection of the brain & the spinal cord-  (i) Bony outer covering: skull for the brain & vertebral column for the spinal cord.

(ii)  Cerebrospinal fluid present in between the three membranes.

*  Action caused by  Nervous tissue  Information  → Nervous tissue →  Brain Muscles → Causes action

*  Path or action-   Nerve impulse  →  Muscle cell  →  Changes shape  due to special proteins

Action caused   ← Shorter form of muscles ← Change shape & arrangement of cell

*  Chemical communication by hormones- (advantages)

(i)      Electrical impulses have their limitations because they reach only those cells connected to the nervous tissue.

(ii)   Also the nerve cells cannot generate & transmit impulses continuously.

(iii) Electrical communication is slower.

*  Hormones- (i)  are chemical messengers secreted by endocrine glands

(ii) Are secreted in small amounts & may act in nearby places or distant places.

(i)Do not take part in the reaction & are destroyed immediately.

*  Hormones are secreted by-     Endocrine glands & Exocrine glands

S. No. Endocrine glands Exocrine glands
1. Ducts absent Ducts present
2. Secrete hormones Secrete enzymes
3. Secreted in blood Secreted in ducts of glands
4. Situated away from the site of action Situated near the site of action

*  Some glands which act as both endocrine & exocrine

Gland Endocrine function Exocrine function
Pancreas Produces insulin & Glucagon hormone. Produces digestive enzyme. (pancreatic amylase)
Testes Produces hormone Testosterone Produces male gametes (reproductive cells)
Ovaries Produces hormone Oestrogen Produces female gametes (reproductive cells)


* Important Endocrine glands, the hormone they secrete & their function Refer to figure 7.7 page no. 124 of N.C.E.R.T  Text book)

Endocrine gland         Hormone       Function
Pituitary gland Growth hormone Body growth, development of bones & muscles(If excess- Gigantism)(If less- Dwarfism)
Thyroid gland Thyroxine Regulates carbohydrate, protein &  fat metabolism( If less- Goitre_
Pancreas Produces insulin & Glucagon hormone Regulates blood sugar levels (if less diabetes is caused)
Testes in males Produces hormone Testosterone Development of secondary male characters like deep voice, beard, etc.
Ovaries in females Produces hormone Oestrogen Development of secondary female characters like mammary glands, menstrual cycle, maintenance of pregnancy.

*  Coordination in plants– Only chemical coordination is present in plants.

* Tropic movements- The movements of plants in the direction of stimulus (positive) or away from it (negative) are called tropic movements. E.g. Phototropism, Geotropism. Chemotropism.

Refer to figure 7.4 & 7.5 page no. 121 of N.C.E.R.T  Text book)

*  Nastic movements -The movements of plants independent of stimuli are called nastic movements. E.g.- Touch me not plant leaves close when touched.

*  Plant hormones (Phytohormones)

Examples- 1. Auxins- Help in growth of root & shoot tips.

2.  Gibberellins- Help in vegetative growth

3.  Cytokinins- Promote cell division

4.  Abscissic acid – Inhibits growth & causes wilting (falling) of leaves

*  Important diagrams-

    1. Structure of neuron (nerve cell)2.Reflex arc 3.Human brain4.Endocrine glands .

*  Important activities-

  1. To compare taste of sugar and food with open & blocked nostrils.
  2. To demonstrate the response of a plant to the direction of light.
  3. To demonstrate hydrotropism.

CBSE Class X Science - Control and Coordination




MARKS-30                                                                          TIME- 70 MINUTES 


  • Questions : 1 to 5 – 1 Mark each
  • Questions : 6 to 9 – 2 Marks each
  • Questions : 10 to 13 – 3 Marks each
  • Question 14 – 5 Marks
  1. Which endocrine gland is unpaired?
  2. Which part of the brain controlled posture and balance of the body?
  3. Where in a neuron, conversions of electrical signal to a chemical signal occur?
  4. Which gland secretes digestive enzyme as well as hormones?
  5. We suddenly withdraw our hand when a pin pricks. Name the type of response involved in this action.
  6. What is a tropic movement? Explain with an example.
  7. What will happen if intake of iodine in our diet is low?
  8. Draw the structure of neuron and label the following on it:
    1. Nucleus
    2. Dendrite
    3. Cell body
    4. Axon
  9. Why are some patients of diabetes treated by giving injections of insulin?
  10. Why is the flow of signals in a synapse from axonal end of one neuron but not the reverse?
  11. What are reflex actions? Explain reflex arc.
  12. What are the major parts of the brains? Mention the functions of each.
  13. How does chemical co – ordination take place in animals?
    1. Name the various plant hormones.
    2. Give physiological effects of hormones on plant growth and development. 


Q1. Which hormone:1. prepares the body for action?2. controls the amount of sugar (glucose) in blood?3. brings about changes in boys at puberty?4. brings about changes in girls at puberty?

Ans. a) Adrenaline                      b) Insulin

c) Testosterone                   d) Oestrogen

Q2. i) Name the hormone produced by thyroid gland.

ii Which mineral is necessary for the synthesis of the above hormone?

iii Name the disease suffer from the deficiency of this mineral.

iv Write the function of the above hormones?

Q3. What is chemotropism? Give one example of chemotropism.



 1 What is the basic unit of nervous system?
 2 How do neuron conduct message from brain to other parts?
 3 What do you mean by CNS?
 4 What are its main parts?
 5 Which part controls reflex action?
 6 What are endocrine glands?
 7 What is the secretion of endocrine gland called?
 8 Name a gland of human body which secretes both enzymes and hormone.
 9 Which plant hormone helps in cell division?
 10 Which hormones help on stem elongation?


 1 Which system of our body is made of organised network for conducting information in the body?
 2 Which part of the neuron receives information?
 3 What is the name of the neuron which remains between the sensory neuron and the motor neuron? Where is it located?
 4 Which part of the brain helps us to do activities like riding a cycle and walking in a straight line?
 5 What are two major types of muscles we have?
 6 What causes change in leave of ‘touch me not’ plant?
 7 Which hormone helps us to prepare to combat adverse condition?
 8 Name a female sex organ which produces gametes as well as female hormone.


1.  Composed of the brain and spinal cord (3 words).
8.  Contains photoreceptors; on the inner posterior portion of eye.
9.  "Inside the mouth"
11. Electrical brain activity recorded with scalp or brain electrodes.(abbreviation).
13. Necessary for hearin
17. Neurotransmitter in brain, spinal cord and peripheral nervous system(abbreviation).
18. Outermost layer of meninges.
19. Neurotransmitter lacking in patients with Parkinson's disease.
21. Supportive cells of the nervous system; "glue".
22. Nerve cell.
23. Photoreceptor that is not used for color vision.
24. Photoreceptor that is used for color vision.
26. The sense of hearing.
29. Opposite of "Yes"
30. Junction between two neurons.
1.  In the brain, it is the outermost layer of the gray matter.
2.  The fifth cranial nerve.
3.  The middle layer of the meninges.
4.  The part of the cell containing chromosomes.
5.  Period of sleep when dreams occur (abbreviation).
6.  The second cranial nerve.
7.  Fat-like substance that surrounds some axons.
10. The first cranial nerve.
12. Fluid that fills the ventricles (abbreviation).
14. Part of neuron that takes information TO the cell body.
16. Short for "mother".
18. Electrical brain activity between 2 and 4 Hz.
20. Part of neuron that takes information AWAY from the cell body.
22. A short written letter.
24. Abbreviation for 1 across.
25. Organ for vision.
27. Opposite of "off".
28. Opposite of "yes".

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