Brain is the central organ of the nervous system of human, and with the spinal cord makes up the central nervous system. It consists of the brainstem, the cerebrum, and the cerebellum. In human body, brain controls most of the activities of the body such as integrating, processing, and coordinating the information which receives from the sense organs, and making decisions and instructions sent to the rest of the body. The brain is protected by, the skull bones of the head.
The cerebrum is the main part of the human brain. The cerebrum is divided into two cerebral hemispheres. The cerebral cortex is an outer layer of grey matter which covering the core of white matter.
Brain is one of the largest and most complex organs in the body of human which is made up of more than 100 billion nerves which communicate in trillions of connections called synapses.
It is the central information processing organ of the body. The weighs of the brain of human is about 1.2 to 1.4kg. It lies in the Cranium of the skull. Brain and spinal cord are surrounded by connective tissue membrane called meninges. There are three meninges in the human’s body such as
- Duramater, an outer layer
- Arachnoid membranes, a middle layer
- Piamater, an inner thin layer.
Human brain is divided into three parts
Let us discuss in detail
- Forebrain – It is the largest part of the brain which monitors complex thoughts action and ideas, and controls intellectual ability. It takes information from environment and communicates to the rest of brain. It decodes and interoperates sound, smell, memory, emotions, visual information, shape and color.
- Midbrain – The midbrain is the region of the brain which connects the forebrain to the hindbrain. Both midbrain and hindbrain together compose the brainstem. The brainstem connects the spinal cord to the cerebrum. The midbrain controls the movement and aids in the processing of auditory and visual information. The oculomotor and trochlear cranial nerves are placed in the midbrain which control eye and eyelid movement. The cerebral aqueduct, a canal which connects the third and fourth cerebral ventricles, is also placed in the midbrain.
- Hindbrain – Hindbrain controls rapid muscular activities such as typing, running and even talking. It also controls respiration, cardiovascular reflexes and gastric secretions.
Spinal cord – It is about 42cm to 45cm long. It conducts impulses to and from the brain and controls most of the reflex activities which provides means of communication between spinal nerves and the brain.
Peripheral Neural System (PNS) – The nerves arising from brains and spinal cord constitute peripheral neural system. There are two types of nerves
- Cranial Nerves
- Spinal Nerves
Spinal cord perform two main functions
- The stimuli are passed from and to the brain through spinal cord.
- It is the centre of spinal reflex actions.