Page 37 - EM BIOLOGY NOTES 10TH CLASS PSR DIGITAL BOOKS

5. COORDINATION
(THE LINKING SYSTEM)

Lesson related
 All living organisms recognize changes in environment and Activities 1, 2, 4 marks
Question and
respond accordingly. videos Answers PDF
pl.scan QR
 The ability to react (Respond) to particular stimulus in a particular situa- pl.scan QR
tion is of great importance for the survival of the organism.
 Stimulus :- Any detectable change in the environment is called stimulus.
 Response :- Response is the reaction of a stimulus done by the organism.
 Ex : Stimulus - Response
Teacher enters into the classroom - Students wishing to teacher
Pinching - Crying/Scolding
Hungry - eating food
Thirsty - Drinking water
Watching snake - Run away from it
touch the hot object - Remove the hand on it
Hearing big sound - Close the ears
 Responses are classified as 1. Voluntary actions
2. Involuntary actions
3. Reflex actions
 1. Voluntary : Talking, walking, running, drinking, eating . . . . . controlled by cerebrum.
2. Involuntary : Heart beating, secretion of enzymes/hormones, forming of urine, digestion
. . . controlled by medulla oblongata and autonomous nervous system.
3. Reflex actions :
 When we touch a hot object, we withdraw our hands from it immediately.
 When something enters into our nose, we sneeze.
 When bright light is focused on our eyes we close our eyes immediately. . . . controlled by
spinal card
Coordination :-
 All functions/responses in the body are carried out by an effort of several systems which
are working together.
 The effort of several systems/organs in the body working together for giving responses is
called coordination.
 Ex :- 1. When we are writing, muscles, nerves, eyes, bones, blood are functioning together
in our body.
2. Our eyes, ears, legs, neck should co-ordinate with each other when we are crossing the
road.
 Nervous system and Endocrine system are the two systems that control and co-ordinate
various organs/systems for giving responses.
Ex : When we saw a snake, we afraid and ran away from that place.
In the above statement there are some sequential events occurs. They are ...
a) Our eye receives the information.
b) Eye sends information to brain through optical nerve.
c) Brain analyse and ordered to muscles of the legs to ran away from that place
immediately.
d) When we are afraid internally the rate of heartbeat increased, the breathing rate will
be faster, blood pressure increased, externally the hair on the body becomes erect.
In the above situation the action of nervous system is limited. All the changes in the
body are carried out under the influence of a chemical change called adrenalin hormone
released by adrenal gland.

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