Question

Cbse 10th biology control and coordination

Answer 1

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