Control and Coordination Class 10 Notes pdf
CBSE Science Notes biology Chapter 7 download

➣  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 Cerebrum-
(i) Main thinking and largest part of the brain.
(ii)  It has 3 main areas-
a)  Sensory area- to receive impulses from sense organs via Receptors
b ) Motor area- control voluntary movements.
c) 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.
(iii) Do not take part in the reaction & are destroyed immediately.

➣ Hormones are secreted by- Endocrine glands & Exocrine glands

➣   Some glands which act as both endocrine & exocrine

➣  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)

➣  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 brain
4.Endocrine glands .

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