Question

Describe the central nervous system in human beings under the following heads: (i) Regions included (ii) Three functions of any one region

Answer 1

 (i) Regions included in central nervous system are the brain and the spinal cord. The brain is further divided into three parts − forebrain, midbrain, and hindbrain. (ii) Three of the functions of the brain are: Forebrain controls intelligence, learning, memory, thinking, speech, etc. Midbrain is associated with the sense of sight and hearing. Hindbrain controls all involuntary actions such as breathing, peristalsis, etc.

Answer 2

The central nervous system in human beings consists of brain and spinal cord.

Brain: Brain is the highest coordinating centre in the body. It is covered by meninges, which is made up of three layers. It is protected by cranium. Brain is broadly divided into:

Forebrain: The forebrain includes cerebrum and olfactory lobes. Cerebrum is the largest part of the brain. It consists of two cerebral hemispheres. Sensory and motor receptors are present in the brain. There are various regions for reception of vision (occipital lobe), reception of sound (temporal lobe), touch, smell, temperature (parietal lobe) and muscular activities (frontal lobe). Olfactory lobes are one in pair and receives olfactory nerves.

Midbrain: It is the small portion of the brain that connects cerebrum with the other parts of the brain and spinal cord.

Hindbrain: It consists of cerebellum, pons and medulla oblongata. Cerebellum is responsible for coordination and adjustment of movement and posture. Pons regulate respiration. Medulla oblongata regulates swallowing, coughing, sneezing and vomiting.

Spinal cord: Medulla oblongata extends downwards, enclosed in vertebral column to form a cylindrical structure known as spinal cord. It is also covered by meninges. It is the reflex centre of the body.