Class 10 Control and Coordination Notes

Notes Previous Years Questions Important Questions

Control and Coordination Notes

Stimulus:-

The change in the environment to which an organism response and react is called stimulus.

Receptors:-

The group of cells present in sense organs which are sensitive to change in environment are called receptors.

There are five types of receptors:-

  • Gustatory receptor
  • Olfactory receptor
  • Photo receptor
  • Phono receptor
  • Thermo receptor

Gustatory receptor:-

  • Present in tongue.
  • Responsible for taste detection.

Olfactory receptor:-

  • Present in nose.
  • Responsible for smell detection.

Photo receptor:-

  • Present in eyes .
  • Responsible for light detection.

Phono receptor:-

  • Present in ears.
  • Responsible for hearing.

Thermo receptor:-

  • Present in skin.
  • Responsible for feeling the touch of external stimuli.

Neuron (nerve cell):-

The structural and functional unit of nervous system is called neuron.

Synapse:- The gap between nerve ending of a neuron and dendrites of other neuron is called synapse.

  • Information is passed through synapse in the form of chemical signal (not in the form of electrical impulse).

Types of neuron:-

  • Sensory neuron:- The neuron that transmits the information from body to central neurons system is called sensory neuron.
  • Motor neuron:- The neuron that transmits the information from central nervous system to different body parts is called motor neuron.
  • Relay neuron:- The neuron that transmits the signal within the central nervous system is called relay neuron.

Reflex action:-

A quick, sudden and immediate response of the body to a stimulus is called reflex action.

Reflex arc:- The pathway through which nerve impulses pass during reflex action is called reflex arc.

Nervous system:-

  • Peripheral nervous system (PNS)
  • Central nervous system (CNS)

Peripheral nervous system (PNS):-

  • Cranial nerves
  • Spinal nerves

Central nervous system (CNS):-

  • Brain
  • Spinal cord

Cranial nerves:- The nerves arising from the brain are called cranial nerves.

Spinal nerves:- The nerves arising from spinal cord are called spinal nerves.

Voluntary actions:- The actions which are controlled by our conscious will are called voluntary actions. Ex:- walking, talking etc.

Involuntary actions:- The actions which are not controlled by our conscious will are called involuntary actions. Ex:- digestion, sweating, blinking of eyes etc.

Brain:-

It is the main coordinating part of the body.

It has three major parts:-

  • Fore brain
  • Mid brain
  • Hind braiin

Fore brain:-

  • It is the main thinking part of the brain.
  • It controls voluntary actions like movement of legs, writing, walking etc.
  • It is responsible for memory.
  • Feeling associated with hunger is controlled by fore brain.
  • It receives sensory impulses from the body and interprets it.

Mid brain:-

  • It controls involuntary actions such as change in the size of pupil, blinking of eyes.

Hind brain:-

  • It controls involuntary actions such as salivation, BP, vomiting, sweating, heart beat etc.

Hind brain has three parts:-

  • Pons
  • Cerebellum
  • Medulla

Pons:-

  • It controls respiratory system.
  • It acts as a bridge between brain and spinal cord.

Cerebellum:-

  • It controls the activities like walking in a straight line, ridding a bicycle, piking up a pencil etc.
  • It is responsible for precision of voluntary action and maintaining the posture and balance of the body.

Medulla:-

  • It controls the involuntary actions like BP, salivation, vomiting etc.

➢ Brain is protected by skull and spinal cord is protected by vertebral column/ backbone.

Limitations of electrical impulses:-

  • Electrical impulse reaches only to those cells that are connected by nervous tissue.
  • Cells can’t continuously create and transmit electrical impulses.
  • Plants do not have any nervous system.

Coordination in plants:-

There are two types of movements in plants:-

  • Independent of growth
  • Dependent of growth

Independent of growth:-

  • It has immediate response to the stimulus.
  • Plants use electrical chemical means to convey the information.
  • In plants, cells change shape and show the movement by changing the amount of water.

In animals, cells change their shape and show movement with the help of specialized proteins found in them.

Dependent of growth:-

  • These movements are tropic i.e, directional in response to stimulus.

➢ The tropic or directional movement can be either towards the stimulus or away from it.

Some tropic movements are:-

  • Phototropism:- Movement towards light or away from it is called phototropism.
    Ex:- Shoots respond by bending towards light while roots respond by bending away from it.
  • Geotropism:- Movement towards or away from gravity is called geotropism.
    Ex:- Roots grow towards gravity i.e., in downward direction while shoots grow away from it i.e., in upward direction.
  • Chemotropism:- Movement towards chemicals or away from it. Ex:- Growth of pollen tube towards ovule.
  • Hydrotropism:- Movement towards water or away from it is called hydrotropism. Ex:- Roots respond by bending towards water while shoots respond by bending away from it.

Plant hormones:-

These are chemical compounds which help to coordinate growth, development and respond to the environment.

Some plant hormones are:-

  • Auxins
  • Gibberlins
  • Cytokinins
  • Abscisic acid

Auxins:-

  • These hormones are synthesized at shoot tip.
  • They help the cells to grow longer.
  • When light is coming from one side of plant auxin diffuses towards the shady side of the shoot and helps the plants to bend towards the light.

Gibberlins:-

  • They help in the growth of stem.

Cytokinins:-

  • They promote cell division.
  • They are present in greater concentration in fruits and seeds.

Abscisic acid:-

  • It inhibits growth.
  • It helps in wilting of leaves.
  • It is called stress hormone.

Animal hormones:-

  • Endocrine System helps in control and coordination through chemical compounds called hormones

Endocrine glands:-

These are ductless glands which secrete hormones directly into bloodstream.

Adrenal gland:-

  • Hormone:- Adrenaline
  • Functions:-
    • It works in stressful situations.
    • It makes heart beat faster to supply more oxygen.
    • It increases the breathing rate.
    • It diverts the blood to skeletal muscles from digestive system and skin.

Thyroid gland:-

  • Hormone:- Thyroxin
  • Function:- It regulates carbohydrates, proteins and fat metabolism to provide best balance for growth.

➢ Iodine is essential for the synthesis of thyroxin.
➢ Goitre is caused due to the deficiency of iodine whose symptom is swollen neck.

Pituitary gland:-

  • Hormone:- Growth hormone
  • Function:- It regulates growth development of the body.

Testis:-

  • Hormone:- Testosterone (Male sex hormone)
  • Functions:- It controls the changes at the time of puberty in males.

Ovary:-

  • Hormone:- Oestrogen (Female sex hormone)
  • Function:- It controls the changes at the time of puberty females.

Pancreas:-

  • Hormone:- Insulin
  • Function:- It regulates blood sugar level.

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