In life there are certain changes in the environment called 'stimuli' to which we respond appropriately. Touching a flame suddenly is a dangerous situation for us. One way is to think consciously about the possibility of burning and then moving the hand. But our body has been designed in such a way that we save ourself from such situations immediately.

(i) Name the action by which we protect ourself in the situation mentioned above and define it.

(ii) Write the role of (a) motor and (b) relay neuron.

(iii) (A) What are the two types of nervous system in human body? Name the components of each of them.

OR

(iii) (B) Which part of the human brain is responsible for:

(a) thinking

(b) picking up a pencil

(c) controlling blood pressure

(d) controlling hunger

(i) The action by which we protect ourself in the situation mentioned above is called a reflex action. A reflex action is an automatic response to a stimulus that involves the activation of a reflex arc, which is a neural pathway that connects the sensory receptor to the motor neuron.

(ii) (a) The role of a motor neuron is to transmit signals from the central nervous system to the muscles or glands, causing them to contract or relax.

(b) The role of a relay neuron is to transmit signals from one neuron to another, allowing the signal to be transmitted over long distances.

(iii) (A) The two types of nervous system in the human body are the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord, while the PNS consists of the nerves that connect the CNS to the rest of the body.

OR

(iii) (B) (a) The part of the human brain responsible for thinking is the forebrain.

(b) The part of the human brain responsible for picking up a pencil is the cerebellum.

(c) The part of the human brain responsible for controlling blood pressure is the medulla.

(d) The part of the human brain responsible for controlling hunger is the hypothalamus.