HUMAN BRAIN

• 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

Hypothalamus:

• 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:

• 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:

• 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

Cerebrum

• 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.

Diencephalon

• Reflex center for muscular activities.
• Centre for certain emotions such as anger.
• Centre for water balance, blood pressure, body temperature, sleep and hunger.

Medulla oblongata

• 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)

Cerebellum

• Maintains posture, equilibrium and muscle tone.
• Coordinates voluntary movements initiated by cerebrum.