Brain Parts and its Functions | A Complete Guide

The brain is the principal organs that run our body. It is protected inside the skull and is the central part of the nervous system. It is classified as a part of the Central Nervous System (CNS) along with the spinal cord. The peripheral nervous system (PNS) comprises of the spinal nerves that branch out from the spinal cord. It also includes the cranial nerves that branch from the brain.

The main parts of the brain are

  1. Cerebrum
  2. cerebellum
  3. Medulla oblongata.

Brain Parts and Functions

The brain controls our thoughts, speech and memory, locomotive movement of the hands and legs and the function of many internal organs.

The brain receives the information from our five sense organs: sight (eyes), hearing (ears), smell (nose), touch (skin) and taste (tongue). Using the stimulus information sent by these five sense organs, the brain makes sense of its surroundings. It is responsible for intelligence, creativity and emotional responses.

The brain is protected inside the bony cranium or skull. Between the brain and cranium, there exist the meninges which act as a cushion for protection. From outer cranium to inner brain, the three layers of meninges are the dura mater, arachnoid mater and pia mater.

Cerebellum

It is located just below the cerebrum. The cerebellum is at the bottom of the brain, behind the brain stem.

The cerebellum has specialized sensors that detect shifts in movement. It sends the signals for the body to adjust its balance.

Our body movements require the coordination of multiple muscle groups. The cerebellum helps in this coordination so that the body can move effectively. The cerebellum also manages eye movements. This cerebellum is involved in learning the movements that require practice like playing an instrument.

Medulla oblongata and pons (brainstem)

The part of the brain is located in the brain stem, anterior to (in front of) the cerebellum.

This section of the brain acts as a relay center between the spinal cord and the thalamus, from the body. The primary function of the thalamus is to transfer information to and from the spinal cord and the cerebellum.

The medulla oblongata helps in many regulatory functions like breathing, digestion, vomiting, swallowing and sneezing. This part of the brain has a center for the respiration and circulation. Multiple neurons travel from the forebrain and midbrain through the medulla.

Pons is the part of the brain stem. It connects the cerebral cortex with the medulla. The pons helps in the transmission of nervous system messages between various parts of the brain and the spinal cord and coordinates the two hemispheres of the brain. Pons deal with respiration, sleep cycles, taste, bladder control, posture, etc.

The cerebrum is divided into several distinct parts separated by fissures. Each cerebral hemisphere has four lobes: The frontal, temporal, parietal, and occipital lobes.

 Lobes of the brain

The lobes of the brain do not work alone. There is a complicated relationship between the lobes of the brain and between the right and left hemispheres.

Frontal lobe

The personality, behavior, judgment, planning, problem-solving or comparison, impulse control, forming memories, empathetic nature is controlled by this lobe.

Further, speech, speaking and writing are controlled by a region called Broca’s area, in the frontal lobe. This helps to speak and understand language.

The primary motor cortex is present in the frontal lobe.  It coordinates voluntary movements like walking and running by generating neural impulses.

The olfactory bulb is located on the ventral surface of the frontal lobe. It receives nerve impulses about various odors detected by the cells in the nasal cavity. Then it processes information about these odors.

Intelligence, concentration, self-awareness, motivation seeking behavior are all managed by this lobe. Most of the brain’s dopamine-sensitive neurons are in the frontal lobe. Dopamine is a neurotransmitter chemical that helps support feelings of motivation.

The central sulcus is a prominent fissure separating the parietal lobe and the frontal lobe. It further divides the primary motor cortex from the primary somatosensory cortex.

Parietal lobe

The parietal lobes reside behind the frontal lobes and above the temporal lobes.

These lobes help us understand spatial orientation and navigation. Being able to identify the position and movement of the body and its parts is an essential function of the parietal lobes.

The somatosensory cortex is another vital region located within the parietal lobes and it helps process touch sensations and sense pain or temperature difference.

Parietal lobes receive the impulses of vision, hearing and other sensory information from a part of the brain called the thalamus and helps process and identify it.

Occipital lobe

This part is the rearmost lobe of the brain, located in the forebrain. It rests upon the tentorium cerebelli, a thick membrane of tissue the separates the cerebrum from the cerebellum.

Interprets vision (color, light, movement, depth) and transmits visual information so that it can be stored in memory.

Temporal lobe

The temporal lobe is located just behind our ears, below the and extends to both sides of the brain.

The main function of the temporal lobes is to process audible sounds. The primary auditory cortex is located in this lobe. It helps in the formation of sensory memories.

The task of understanding language is performed in the Wernicke’s area of this lobe.

Cortex

This is the outer surface of the cerebrum called the cortex. It has a folded appearance due to neurons. The foldings present in the cortex increases the brain’s surface area allowing more neurons to fit. A fold is referred to as a gyrus and the valley between is a sulcus. The neurons are gray in color – gray matter. Beneath the cortex are long nerve fibers (axons) that connect brain areas to each other — called white matter.

Deep structures

This includes the inner structures of the brain. This consists of

Thalamus

It serves as a relay station for almost all information that comes and goes to the cortex. It helps in pain sensation, attention, and memory. It acts as a transmission center for all the sensory information.

Hypothalamus

It is the master control of the autonomic nervous system. It is positioned on the floor of the third ventricle. It regulates the secretion of hormones. It plays a role in hunger, thirst, sleep cycles and sexual response. It also has control over body temperature, blood pressure and emotions.

Pituitary gland

It is located in the sella turcica, a small pocket of bone at the base of the skull. The pituitary gland is fixed to the bottom of the hypothalamus of the brain by the pituitary stalk. It is known as the master gland, as it controls other endocrine glands in the body by secreting hormones that control stress levels, sexual cycles, etc.

Limbic system

It is the center of our emotional responses and memory. The cingulate gyri, hypothalamus, amygdala (for emotional reactions) and hippocampus (for memory) are all included in this system.

Pineal gland

It is located near the thalamus, behind the third ventricle. It secretes melatonin and helps regulate the body’s internal clock and circadian rhythms. It also plays some role in sexual development.

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