Question

discuss the brain and its parts (5 mark)

Answer 1

The human brain is the central organ of the human nervous system, and with the spinal cord makes up the central nervous system. The brain consists of the cerebrum, thebrainstem and the cerebellum. It controls most of the activities of the body, processing, integrating, and coordinating the information it receives from the sense organs, and making decisions as to the instructions sent to the rest of the body. The brain is contained in, and protected by, the skull bones of thehead. The cerebrum is the largest part of the human brain. It is divided into two cerebral hemispheres. The cerebral cortex is an outer layer of grey matter, covering the core ofwhite matter. The cortex is split into theneocortex and the much smaller allocortex. The neocortex is made up of six neuronal layers, while the allocortex has three or four. Each hemisphere is conventionally divided into four lobes – the frontal, temporal,parietal, and occipital lobes. The frontal lobe is associated with executive functionsincluding self-control, planning, reasoning, and abstract thought, while the occipital lobe is dedicated to vision. Within each lobe, cortical areas are associated with specific functions, such as the sensory, motor andassociation regions. Although the left and right hemispheres are broadly similar in shape and function, some functions areassociated with one side, such as language in the left and visual-spatial ability in the right. The hemispheres are connected bycommissural nerve tracts, the largest being the corpus callosum.

Answer 2

This is the cut section of a Human Brain. The parts and their functions are given below :

1. Cerebrum: It is the largest part of the brain and has two hemispheres. Cerebrum is a highly developed part of the Central Nervous System and controls various functions like Speech, Vision, the thought process, movement of limbs, creativity and emotions. Cerebrum itself has many different lobes for different functions.

2. Corpus Callosum: It serves as a bridge to coordinate the activities between the two Cerebral hemispheres.

3. Ventricles: These are open spaces in the brain for the production and circulation of the Cerebrospinal fluid(CSF) which maintains the Intracranial Pressure and Nutrition of the Brain and Spinal Cord. Actually, CSF is produced in the choroid plexus formed by small capillaries lining the ventricles. Ventricles are Four in number. The ventricle in the picture is one of the Lateral Ventricles.

4.Cerebellum: It is present below and behind the Cerebral hemispheres. Cerebellum controls the balance(equilibrium) of the body and prevents falls while running or walking. It also controls repetitive movements and muscle tone.

5. Thalamus: Thalamus serves the process of consciousness and sleeping.

6. Hypothalamus: It serves as a master endocrine gland the body releasing various chemicals to regulate the function of Pituitary gland. Also regulates body temperature.

7. Pons: It serves as a for the nerve fibres coming from the cerebrum and going down to the spinal cord. It also gives rise to a number of cranial nerves.

8.Medulla: It is responsible for the maintainence of breathing and heart rate. Certain cranial nerves also arise from medulla. Medulla joins the brain to spinal cord.