INTRODUCTION:

During development of an embryo of vertebrate, the formation of the brain begins as a swelling at the front end of the spinal cord. Later, this swelling develops thick nerve fibres which connect to receptors such as the eyes, the skin, the nose etc. generally, the brain functions in coordinating simple reflex behavior and is capable or remembering and also learning the human brain is made up of over billion neurones and many thousand synapses.

The brain contains a fluid which is called the cerebrospinal fluid which help is nourishing and protecting the brain. The brain is made up of three main region

• The fore brain
• The mid brain
• The hind brain

The fore brain is the largest part of the brain

1. The fore brain: the fore brain is made up of the cerebrum. Which is divided into two cerebral hemisphere, the left and the right hemisphere. The cerebrum is concern with intelligent speech, vision, memory, wind power etc. in man they are also concern with emotion
2. The hypothalamus:  provide reflex or involuntary control concerned with homeastatic mechanism such as water balance, carbondioxide level in blood and regulation of body temperature. It also control taste appetide and sleep. It also produce ADH responsible for osmoregulation and oxytocin that causes labour. NB: the fore brain is made up of the cerebrum and hypothalamus.
3. Mid brain: the mid brain contains relay nerve fibre it plays a part in sight.
4. The hind brain: the hind brain is made up of the cerebellum and the medulla oblongata
5. Cerebellum: it is responsible for body balance and posture. It also controls muscular coordination. It receive impulses from the semi circular canals of the ear
6. Medulla oblongata: it controls involuntary and reflex activity of the body such as heart beat, contraction and dilation of blood vessels, swallowing, peristalses, syneezing, coughing and vomiting. It also control wakefulness. When the wakefulness counter become inactive we fall asleep.