Functions of Major Parts of the Brain

Structurally the brain is divided into three major regions i.e. forebrain, mid-brain and hindbrain.

The Forebrain

Made of;

(a) Cerebral hemispheres

(b) Thalamus

(c) Hypothalamus

(d) Pituitary gland

Cerebrum

It is the largest part of the brain.

It is divided into the right and left cerebral hemispheres.

The outer part is highly folded increasing surface area for densely packed nerve cells.

Functions of cerebrum

• Integration of sensory impulses such as vision, hearing and taste.
• Controls voluntary body movements e.g. walking, lips and neck.
• Controls learning, memory and human individuality.

Thalamus

It is an important relay centre.

It contains receptors for pain and pleasure.

Hypothalamus

Located below the thalamus hence the name.

Functions

• Involved in homeostatic processes e.g. thermoregulation and osmoregulation.
• Controls appetite and sleep.

Pituitary gland

It is attached to the hypothalamus and projects downwards from it.

It is the master endocrine gland controlling the rest of the endocrine glands.

Mid brain (corpora quadrigemia)

Made of a small stalk that connects the forebrain and hindbrain.

It relays impulses between nerves from the spinal cord and the forebrain.

Hindbrain

Made of;

• Cerebellum
• Pons
• Medulla oblongata

Cerebellum

Located under the cerebral hemispheres.

It is highly folded to increase surface area so as to carry a large number of nerve cells.

Function: Maintenance of body balance and posture. This is achieved by controlling and coordinating muscular movements.

Medulla oblongata

Found below the cerebellum and is connected to the spinal cord.

Functions

• Control involuntary activities such as;
• Breathing
• Sneezing, coughing, swallowing, vomiting and Salivation.
• Blood circulation, vasoconstriction and vasodilation.
• Heart rate and force of heart beat.

Pons

Acts as a relay centre between cerebellum, spinal cord and the rest of the brain.

Cranial Nerves

These nerves arise from the brain and form part of the peripheral nerve system associated with receptors and effectors in the head.

In human beings there are 12 pairs of cranial nerves confined to the head and neck.

This may be purely sensory, motor or mixed.

Examples of cranial nerves are optic, auditory, olfactory and facial nerves.

In addition, there are sensory and motor nerves which innervate the face and jaws.

The tenth cranial nerve – the vagus nerve – innervates the heart, lungs, diaphragm and the gut.

Structure and Function of the Brain