- Human brain is a highly complex organ; which is mainly composed of the nervous tissue.
- The tissues are highly folded to accommodate a larger surface area in less space.
- The brain is covered by a three-layered system of membranes; called meninges.
- Cerebrospinal fluid is filled between the meninges.
- The CSF provides cushion to the brain against mechanical shocks.
- Furthermore, the brain is housed inside the skull for optimum protection.
The human brain can be divided into three regions, viz. forebrain, midbrain and hindbrain.
PARTS OF HUMAN BRAIN
Forebrain: It is composed of the cerebrum.
Midbrain: It is composed of the hypothalamus.
Hindbrain: It is composed of the cerebellum, pons and medulla oblongata.
Some main structures of the human brain are explained below.
Cerebrum: The cerebrum is the largest part in the human brain. It is divided into two hemispheres; called cerebral hemispheres.
FUNCTIONS OF CEREBRUM:
- The cerebrum controls the voluntary motor actions.
- It is the site of sensory perceptions; like tactile and auditory perceptions.
- It is the seat of learning and memory
- The hypothalamus lies at the base of the cerebrum.
- It controls sleep and wake cycle (circadian rhythm) of the body.
- It also controls the urges for eating and drinking.
- Cerebellum lies below the cerebrum and at the back of the whole structure.
- It coordinates the motor functions.
- When you are riding your bicycle; the perfect coordination between your pedaling and steering control is achieved by the cerebellum.
- Medulla forms the brain stem; along with the pons. It lies at the base of the brain and continues into the spinal cord.
- Medulla controls various involuntary functions; like heartbeat, respiration, etc.
FUNCTIONS OF DIFFERENT PART OF THE BRAIN
- Seat of mental abilities, controls thinking, memory, reasoning, perception, emotions and speech.
- Interprets sensations and responds to cold, heat, pain and pressure.
- Relay center for sensory impulses, such as pain, temperature and light.
- Reflex center for muscular activities.
- Centre for certain emotions such as anger.
- Centre for water balance, blood pressure, body temperature, sleep and hunger.
- Coordinates reflexes like swallowing, coughing, sneezing and vomiting.
- Contains center for cardiac, respiratory and vasomotor activities. (Vasomotor refers to actions upon a blood vessel which alter its diameter)
- Maintains posture, equilibrium and muscle tone.
- Coordinates voluntary movements initiated by cerebrum.