Brain and its parts described

Brain and it’s parts description in the most uncomplicated and easily understandable manner –

Your Brain is the most complex organ of the body. It has the capacity to think, reason, apply logic, and so much more. All the credit for this thinking ability goes to our brain, a tiny organ weighing about 3 pounds, which is what makes us so special.

A spongy pink mass made up of billions of microscopic nerve cells linked together in an electronic network.The brain is protected from damage by several layers of defenses. Outermost are the bones of the skull. Beneath the skull are the meninges, a series of sturdy membranes that surround the brain and spinal cord. Inside the meninges, the brain is cushioned by fluid.

Parts of brain

  • Cerebrum (Largest part of brain)
  • Cerebellum (located under cerebrum)
  • Brainstem ( relay center connecting the cerebrum and cerebellum to the spinal cord)

Cerebrum (responsible for your thoughts and actions).

Cerebrum controls all our conscious actions and thoughts, analyses sensory data and stores information. The diencephalon is inside the cerebrum above the brain stem. As with the other parts of the brain, it is divided into sections. These include the thalamus, hypothalamus, and epitheliums. The surface of the cerebral hemispheres is composed of a thin shell of grey matter, the cerebral cortex which is 2–4 mm thick. The cortex is thrown into numerous convolutions or gyri separated by furrows called sulci.

Pituitary Gland –

This releases chemicals called hormones in your blood. It is of two types anterior and posterior pituitary. The pituitary gland is just beneath the hypothalamus, connected to it by the pituitary stalk. It is separated into anterior (glandular) and posterior (neural) portions. The pituitary gland is an endocrine structure which releases hormones that control growth, metabolism and sexual function. It mainly regulates other glands (rather than having a direct physiological effect) and is therefore referred to as the ‘master gland’ of the endocrine system. Its activity is controlled in turn by soluble mediators released by the hypothalamus. These reach the anterior lobe of the pituitary gland via a capillary network called the hypothalamo-pituitary portal system. The hypothalamus communicates with the posterior lobe more directly via a bundle of nerve fibres termed the hypothalamo-hypophyseal tract.

Hypothalamus – It regulates sleep, hunger, body temperature. The hypothalamus controls the ANS and endocrine system and is involved in the maintenance of homeostasis.

Thalamus – It relays sensory signals from body to cerebrum where they are decoded and analyses takes place.  The thalamus is known as the ‘gateway’ to the cerebral cortex, since most ascending sensory pathways relay in one of its nuclei in order to reach their cortical targets. 


This complex folded structure helps control balance and movement. The cerebellum (“little brain”) is a structure that is located at the back of the brain, underlying the occipital and temporal lobes of the cerebral cortex .

Although the cerebellum accounts for approximately 10% of the brain’s volume, it contains over 50% of the total number of neurons in the brain. Motor commands are not initiated in the cerebellum; rather, the cerebellum modifies the motor commands of the descending pathways to make movements more adaptive and accurate. 

The cerebellum is involved in the following functions:

Maintenance of balance and posture. – The cerebellum is important for making postural adjustments in order to maintain balance. Through its input from vestibular receptors and proprioceptors, it modulates commands to motor neurons to compensate for shifts in body position or changes in load upon muscles. Patients with cerebellar damage suffer from balance disorders, and they often develop stereotyped postural strategies to compensate for this problem (e.g., a wide-based stance).

Coordination of voluntary movements.- Most movements are composed of a number of different muscle groups acting together in a temporally coordinated fashion. One major function of the cerebellum is to coordinate the timing and force of these different muscle groups to produce fluid limb or body movements.

Motor learning. The cerebellum is important for motor learning. The cerebellum plays a major role in adapting and fine-tuning motor programs to make accurate movements through a trial-and-error process (e.g., learning to hit a baseball).

Cognitive functions. Although the cerebellum is most understood in terms of its contributions to motor control, it is also involved in certain cognitive functions, such as language. Thus, like the basal ganglia, the cerebellum is historically considered as part of the motor system, but its functions extend beyond motor control in ways that are not yet well understood.

Brain Stem – Connected to Spinal Cord, it links the rest of the body to the bain and controls heartbeat and breathing.

Midbrain The midbrain helps control eye movement and processes visual and auditory information.

The pons – is the largest part of the brainstem, located above the medulla and below the midbrain. It is a group of nerves that function as a connection between the cerebrum and cerebellum (pons is Latin for bridge). The pons is a horseshoe-shaped collection of nerve fibres located in the anterior part of the posterior cranial fossa.

Medulla oblongata, – also called medulla, the lowest part of the brain and the lowest portion of the brainstem. The medulla oblongata is connected by the pons to the midbrain and is continuous posteriorly with the spinal cord, with which it merges at the opening (foramen magnum) at the base of the skull. It carries out and regulates life sustaining functions such as breathing, swallowing and heart rate.As a part of the brain stem, it also helps transfer neural messages from the brain to the spinal cord.

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