Question

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.

1. Name the action by which we protect ourself in the situation mentioned above and define it.    (1)
2. Write the role of (a) motor and (b) relay neuron.   (1)
3. 1. What are the two types of nervous systems in the human body? Name the components of each of them.    (2)
      OR
   2. Which part of the human brain is responsible for:   (2)
      1. thinking
      2. picking up a pencil
      3. controlling blood pressure
      4. controlling hunger

Answer 1

i. Reflex action: It is an involuntary and instantaneous movement in response to a stimulus that occurs without conscious thought.

ii.

1. Motor neurons transmit impulses from the CNS to the effector to produce movement.
2. Relay neurons are found in the inspinal cord. It transmits signals between sensory neurons and motor neurons, helping in reflex actions.

iii. A. There are two different kinds of neurological systems: the peripheral nervous system (PNS) and the central nervous system (CNS). The brain and spinal cord make up the CNS. All nerves, including spinal and cranial nerves, are part of the PNS.

OR

B.

1. Cerebrum
2. Cerebellum
3. Medulla oblongata
4. Hypothalamus