CBSE Class 10 Science Control And Coordination Notes Set 03

Control and Coordination

Living organisms respond and react to various stimuli like heat, light, cold, touch, pressure etc. Plants and animals both respond to stimuli but in different manner. 

Example : withdrawl of hand on touching a hot object.

Control and Coordination in Animals

It is brought about in all animals with the help of two main systems

a) Nervous System b) Endocrine System

Nervous System :

Functions

i) To receive the information from environment

ii) To receive the information from various body parts. (Stimuli ® Response)

iii) To act accordingly through muscles and glands.

Stimulus : Any change in environment or within that bring about the reaction eg: touching a hot plate.

Response : The reaction of our body to these changes. eg. withdrawal of our hand How do we detect that we are touching a hot object?

Receptors : Are specialised tips of some nerve cells that detect the information from the environment.

Synapse : The point of contact between the terminal branches of axon of one neuron with the dendrite of another neuron is called synapse.

Reflex Action

A quick, sudden, immediate response of the body to the certain stimuli that involves Spinal cord. eg. (not brain) withdrawal of hand, knee jerk etc.

Reflex arc : The pathway through which impulses pass is called reflex arc.

Response
Responses are of three main types

Voluntary : Controlled by fore brain
eg. Talking, Writing

Involuntary : Controlled by mid and hind brain
eg. Heart beat, vomiting, regulation of heartbeat

Reflex action : controlled by spinal cord
eg. Withdrawl of hand on touching a hot object.

Human Brain

Human brain has three major parts or regions
a) Forebrain b) Mid Brain c) Hind Brain
FOREBRAIN
Most complex/specialized part of the brain is CEREBRUM

FUNCTIONS :
1. Thinking part of the brain
2. Control the voluntary actions.
3. Store information (Memory)
4. Centre associated with HUNGER
5. Receives sensory impulses from various body parts and integrates it

PROTECTION OF BRAIN AND SPINAL CORD 

Plant hormones :
Are chemical compounds which help to coordinate growth, development and responses to the environment.
Plant hormones : Main plant hormones are :
a) Auxin : [Synthesized at shoot tip]
Function : – Helps in growth
Phototropism : more growth of cells towards light.
b) Gibberellin : Helps in the growth of the stem
c) Cytokinins : Promotes cell division
d) Abscisic acid : Inhibits growth, cause witting of leaves.
(Stress hormone)

Hormones in Animals
Hormones : These are the chemical messengers secreted in very small amounts by specialised tissues called ductless glands. They act on target tissues/organs usually away from their source.
Endocrine System helps in control and coordination through chemical compounds called HORMONES 

IODISED SALT IS NECESSARY BECAUSE :
Iodine mineral is essential part of thyronine hormone so it is important that we must consume iodised salt as in turn it is essential for thyroid gland as it controls carbohydrate, proteins and fat metabolism for best balance of growth deficiency of iodine might cause disease called goitre.

Diabetes :
Cause : It is due to deficiency of Insulin hormone secreted by Pancreas that is responsible to lower/control the blood sugar levels.
Treatment : Patients have to internally administer injections of insulin hormone which helps in regulating blood-sugar level.

Feedback Mechanism
makes sure that hormones should be secreted in precise quantities and at right time, which is regulated by feedback mechanism. 

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