What is the brain?

The mind is a complicated organ the controls thought, memory, emotion, touch, engine skills, vision, breathing, temperature, hunger and every process that regulates ours body. Together, the mind and spinal cord that extends from it consist of the central nervous system, or CNS.

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What is the mind made of?

Weighing around 3 pounds in the average adult, the brain is about 60% fat. The remaining 40% is a combination of water, protein, carbohydrates and salts. The mind itself is a no a muscle. It includes blood vessels and also nerves, including neurons and glial cells.

What is the gray matter and white matter?

Gray and also white matter are two different regions the the main nervous system. In the brain, gray matter refers to the darker, external portion, when white matter describes the lighter, inner ar underneath. In the spinal cord, this stimulate is reversed: The white matter is ~ above the outside, and also the gray issue sits within.


Gray issue is mostly composed of neuron somas (the round central cell bodies), and white matter is greatly made the axons (the lengthy stems that connects neurons together) wrapped in myelin (a protective coating). The various composition of neuron components is why the two appear as separate shades on details scans.


Each an ar serves a different role. Gray matter is mainly responsible because that processing and also interpreting information, when white matter transmits that info to various other parts that the nervous system.

How go the mind work?

The mind sends and also receives chemical and also electrical signal throughout the body. Different signals control different processes, and also your mind interprets each. Some make you feeling tired, because that example, while others make you feeling pain.

Some messages are maintained within the brain, when others space relayed through the spine and throughout the body’s large network the nerves to far-off extremities. To carry out this, the central nervous mechanism relies on billions of neurons (nerve cells).

Main components of the mind and their Functions

At a high level, the mind can be separated into the cerebrum, brainstem and also cerebellum.



The cerebrum (front the brain) comprises gray matter (the cerebral cortex) and also white issue at the center. The largest part of the brain, the cerebrum initiates and coordinates movement and also regulates temperature. Other locations of the cerebrum enable speech, judgment, thinking and also reasoning, problem-solving, emotions and learning. Other features relate to vision, hearing, touch and other senses.

Cerebral Cortex

Cortex is Latin for “bark,” and describes the outer gray matter covering of the cerebrum. The cortex has a large surface area because of its folds, and comprises about half of the brain’s weight.

The cerebral cortex is divided into 2 halves, or hemispheres. It is extended with ridges (gyri) and also folds (sulci). The 2 halves sign up with at a large, deep sulcus (the interhemispheric fissure, AKA the medial longitudinal fissure) that runs native the front of the head come the back. The ideal hemisphere controls the left side of the body, and the left half controls the best side of the body. The 2 halves interact with one one more through a large, C-shaped structure of white matter and nerve pathways referred to as the body callosum. The corpus callosum is in the facility of the cerebrum.


The brainstem (middle the brain) connects the cerebrum through the spinal cord. The brainstem includes the midbrain, the pons and the medulla.

Midbrain. The midbrain (or mesencephalon) is a very facility structure through a selection of various neuron clusters (nuclei and colliculi), neural pathways and also other structures. These features facilitate various functions, native hearing and movement come calculating responses and also environmental changes. The midbrain also contains the substantia nigra, an area affected by Parkinson’s disease that is well-off in dopamine neurons and component of the basal ganglia, which allows movement and coordination. Pons. The pons is the origin for 4 of the 12 cranial nerves, which allow a range of activities such together tear production, chewing, blinking, focusing vision, balance, hearing and facial expression. Named for the Latin word because that “bridge,” the pons is the connection in between the midbrain and the medulla. Medulla. At the bottom that the brainstem, the medulla is where the brain meets the spinal cord. The medulla is essential to survival. Features of the medulla regulate plenty of bodily activities, consisting of heart rhythm, breathing, blood flow, and oxygen and also carbon dioxide levels. The medulla to produce reflexive activities such together sneezing, vomiting, coughing and also swallowing.

The spinal cord extends indigenous the bottom the the medulla and through a large opening in the bottom the the skull. Supported by the vertebrae, the spinal cord carries messages to and also from the mind and the rest of the body.


The cerebellum (“little brain”) is a fist-sized section of the mind located in ~ the ago of the head, listed below the temporal and also occipital lobes and over the brainstem. Prefer the cerebral cortex, it has two hemispheres. The outer section contains neurons, and also the inside area communicates through the cerebral cortex. Its role is to name: coordinates voluntary muscle movements and also to maintain posture, balance and also equilibrium. Brand-new studies are experimenting the cerebellum’s duties in thought, emotions and also social behavior, as well as its feasible involvement in addiction, autism and also schizophrenia.

Brain Coverings: Meninges

Three class of safety covering dubbed meninges surround the mind and the spinal cord.

The outermost layer, the dura mater, is thick and tough. It has two layers: The periosteal layer of the dura mater currently the inside dome that the skull (cranium) and the meningeal class is listed below that. Spaces in between the layers permit for the i of veins and also arteries the supply blood circulation to the brain. The arachnoid mater is a thin, weblike class of connective tissue that does not contain nerves or blood vessels. Listed below the arachnoid mater is the cerebrospinal fluid, or CSF. This fluid cushions the entire main nervous mechanism (brain and also spinal cord) and also continually circulates around these structures to eliminate impurities. The pia mater is a slim membrane that hugs the surface ar of the mind and follows its contours. The pia mater is rich with veins and arteries.


Lobes the the mind and What lock Control

Each mind hemisphere (parts of the cerebrum) has four sections, dubbed lobes: frontal, parietal, temporal and also occipital. Every lobe controls particular functions.


Frontal lobe. The largest lobe of the brain, located in the front of the head, the frontal lobe is involved in personality characteristics, decision-making and movement. Recognition of odor usually involves parts that the frontal lobe. The frontal lobe has Broca’s area, which is associated with speech ability. Parietal lobe. The middle part of the brain, the parietal lobe help a person identify objects and also understand spatial relationship (where one’s human body is compared with objects roughly the person). The parietal lobe is likewise involved in interpreting pain and also touch in the body. The parietal lobe homes Wernicke’s area, which helps the brain understand spoken language. Occipital lobe. The occipital lobe is the back component of the brain that is involved with vision. Temporal lobe. The sides of the brain, temporal lobes are connected in temporary memory, speech, musical rhythm and some degree of smell recognition.

Deeper structures Within the Brain

Pituitary Gland

Sometimes dubbed the “master gland,” the pituitary gland is a pea-sized structure found deep in the mind behind the bridge of the nose. The pituitary gland governs the function of other glands in the body, regulating the flow of hormones from the thyroid, adrenals, ovaries and testicles. That receives chemical signal from the hypothalamus with its stalk and also blood supply.


The hypothalamus is located over the pituitary gland and also sends it chemical messages that regulate its function. It regulates body temperature, synchronizes sleep patterns, controls hunger and thirst and additionally plays a role in some aspects of memory and also emotion.


Small, almond-shaped structures, one amygdala is located under each fifty percent (hemisphere) of the brain. Consisted of in the limbic system, the amygdalae manage emotion and memory and also are linked with the brain’s prize system, stress, and also the “fight or flight” an answer when who perceives a threat.


A bent seahorse-shaped organ on the underside of each temporal lobe, the hippocampus is component of a larger structure referred to as the hippocampal formation. It support memory, learning, navigation and perception of space. It receives details from the cerebral cortex and may pat a role in Alzheimer’s disease.

Pineal Gland

The pineal gland is situated deep in the mind and attached by a stalk come the optimal of the 3rd ventricle. The pineal gland responds come light and also dark and also secretes melatonin, i m sorry regulates circadian rhythms and also the sleep-wake cycle.

Ventricles and Cerebrospinal Fluid

Deep in the mind are four open areas with passageways between them. They additionally open into the central spinal canal and also the area beneath arachnoid great of the meninges.

The ventricles to produce cerebrospinal fluid, or CSF, a watery fluid that circulates in and also around the ventricles and the spinal cord, and between the meninges. CSF surrounds and cushions the spinal cord and also brain, washes the end waste and impurities, and delivers nutrients.


Blood it is provided to the Brain

Two to adjust of blood vessels supply blood and also oxygen to the brain: the vertebral arteries and also the carotid arteries.

The outside carotid arteries extend up the political parties of your neck, and also are where you deserve to feel your pulse when you touch the area v your fingertips. The interior carotid arteries branch into the skull and also circulate blood come the front part of the brain.

The vertebral arteries monitor the spinal column right into the skull, whereby they join together at the brainstem and type the basilar artery, which offers blood come the rear parts of the brain.

The circle of Willis, a loop of blood vessels close to the bottom the the mind that connects major arteries, circulates blood native the former of the mind to the earlier and help the arterial systems interact with one another.


Cranial Nerves

Inside the cranium (the dome of the skull), there are 12 nerves, referred to as cranial nerves:

Cranial nerve 1: The an initial is the olfactory nerve, which enables for your sense of smell. Cranial nerve 2: The optic nerve governs eyesight. Cranial nerve 3: The oculomotor nerve controls pupil an answer and other motions of the eye, and branches the end from the area in the brainstem whereby the midbrain meets the pons. Cranial nerve 4: The trochlear nerve controls muscles in the eye. It emerges from the ago of the midbrain component of the brainstem. Cranial nerve 5: The trigeminal nerve is the largest and also most complicated of the cranial nerves, through both sensory and also motor function. That originates from the pons and also conveys emotion from the scalp, teeth, jaw, sinuses, components of the mouth and face to the brain, permits the function of chewing muscles, and also much more. Cranial nerve 6: The abducens nerve innervates several of the muscle in the eye. Cranial nerve 7: The facial nerve supports face movement, taste, glandular and other functions. Cranial nerve 8: The vestibulocochlear nerve facilitates balance and hearing. Cranial nerve 9: The glossopharyngeal nerve permits taste, ear and throat movement, and has many an ext functions. Cranial nerve 10: The vagus nerve allows sensation roughly the ear and also the cradle system and controls motor activity in the heart, throat and also digestive system. Cranial nerve 11: The accessory nerve innervates certain muscles in the head, neck and also shoulder. Cranial nerve 12: The hypoglossal nerve provides motor activity to the tongue.

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The an initial two nerves originate in the cerebrum, and also the remaining 10 cranial nerves emerge from the brainstem, which has actually three parts: the midbrain, the pons and also the medulla.