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Tuesday, 18 July 2017

Parts of the brain and their function

The brain is made up of three major regions: the forebrainmidbrain and hindbrain. When viewed in a longitudinal section, it is observed to be composed of several parts.

The root of the forebrain is enlarged and greatly folded to form the cerebrum: which has a large surface area to accommodate the millions of brain cells. It controls all voluntary activities of the body. It is also the part of the brain that is concerned with intelligence, memory, will power, imagination, reasoning, vision, speech and taste. The olfactory lobes of the forebrain are concerned with smell.

The hypothalamus is responsible for involuntary activities, e.g. water balance, carbon dioxide levels in the blood, regulation of body temperature, appetite, sleep and thirst. The hypothalamus controls the pituitary gland and thereby, serves as a link between the nervous and endocrine systems. The pituitary gland secretes a number of hormones which control various body activities including the activity of some other endocrine glands.

The cerebellum is separated from the brain stem by the fourth ventricle. The cerebellum has two portions that are joined by a narrow median portion. Each portion is primarily composed of a white matter, which in longitudinal section is shown to have a treelike pattern. Overlying the white matter is a thin layer of grey matter that forms a series of complex folds. The cerebellum or hindbrain receives sensory input from the eyes, ears, joints and muscles about the present position of the body parts, and it also receives motor output from cerebral cortex about where these parts should be located. After integrating the information, the cerebellum sends motor impulses by way of the brain stem to the skeletal muscles. In this way, the cerebellum maintains posture and balance. It also ensures that all of the muscles work together to produce smooth, coordinated voluntary movements. The cerebellum assists the learning of new motor skills such as, playing the piano or hitting a baseball.

The medulla oblonga contains a number of reflex centres for regulating heartbeat, breathing and vasoconstriction [blood pressure). It also contains the reflex centres for vomiting, coughing, sneezing, hiccupping and swallowing. The medulla oblonga lies just superior to the spinal cord and it contains tracts that ascend or descend between the spinal cord and higher brain centres.

1 comment:

  1. You write every blog post so well. Keep the hard work going and good luck.