The Hind Brain and its Functions

The posterior region of the brain is called hind brain. It consists of pons varolli, cerebellum and medulla oblongata.

i. Pons varolli:

a. It appears as a rounded bulge on the underside of the brain stem and contains a cross band of nerve fibres connecting cerebrum, cerebellar lobes, medulla oblongata and spinal cord.

b. It also contains several nuclei.

ii. Cerebellum:

a. It is the second largest part of the brain and consists of two lateral hemispheres and a central vermis.

b. It is composed of white matter with a thin layer of grey matter, the cortex.

c.The white matter intermixes with the grey matter and shows a tree-like pattern called arbor vitae.

d. The surface of cerebellum shows convolutions (gyri and sulci) a number of nuclei lie deep within each lateral or cerebellar hemisphere.

e.Over 30 million neurons lie in the cortex.

f. Three pairs of myelinated nerve bundles called cerebullar penduncles connect cerebellum to the other parts of CNS.

g. Functions:

1.It is an important centre which maintains equilibrium of body, posture, balancing orientation, moderation of voluntary movements, maintenance of muscle tone.

2. It is a regulatory centre for neuromuscular activities and controls the rapid activities like walking, running, speaking etc.

3. All activities of cerebellum are involuntary (though may involve learning in early stages).

iii. Medulla oblongata: 

a. It is the posterior conical part of the brain and continues as the spinal cord. 

b. It has inner grey matter and outer white matter.

c. Its roof has the posterior choroid plexes for secretion of CSF.

d. The posterior choroid plexes also shows three openings - a pair of lateral foramen of Luschka and a median foramen of Magendie.

e. Functions:

1. It controls involuntary vital functions like heart beat, respiration, vasomotor activities and peristalsis(Peristalsis is like a wave-like squeezing and relaxing motion in your digestive tract that helps push food and liquids through your body.).

2. It also controls non vital reflex activities like coughing, swallowing, sneezing, vomiting, yawning, etc.