What are the major components of the brain? what are the principal functions of each?

Human brain is divided into 3 major parts: fore brain, mid brain and hind brain.

Explanation:

Human brain is covered tough tissue called meninges which includes outer dura mater, middle arachnoid membrane and inner pia mater.

Human brain is divided into 3 major parts:

1. Fore brain: it consists of:

a) Olfactory bulb: It receives the impulses pertaining to smell from the olfactory epithelium.

b) Cerebrum: It forms the major part of brain. It is divided into right and left cerebral hemispheres by a longitudinal fissure. It has 3 major functional areas:

i) sensory areas: receive and interpret the sensory impulses

ii) motor areas: controls voluntary muscular movements

iii) association areas: deal with memory and communications

Each cerebral hemisphere is divided into frontal, parietal, temporal and occipital lobes.

c) Diencephalon: Roof of diencephalon is called epithalamus, it is non-nervous part. Lying superior to mid brain is thalamus, which is the coordinating center for the sensory and motor signalling. At the base of thalamus is hypothalamus, which serves as osmoregulatory, thermoregulatory, thirst, hunger and satiety centers.

2. Mid brain: It is located between thalamus of forebrain and pons Varolii of hind brain. It consists of 4 rounded lobes called corpora quadrigemina (4 optic lobes). The two superior colliculi are concerned with visual reflexes and the inferior colliculi are concerned with auditory reflexes.

3. Hind brain: Comprises of cerebellum, pons Varolii and medulla oblongata.

Cerebellum is the little brain, it controls and coordinates the locomotor movements. Pons act as the relay station between cerebellum, spinal cord and rest of the brain. Medulla includes the cardiovascular and respiratory centers, the centers for swallowing, vomiting, coughing, sneezing and hiccupping.  

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