What exactly is the brain?
The brain is a complicated organ that regulates every action in our body, including thought, memory, emotion, touch, motor skills, vision, respiration, temperature, and hunger. The central nervous system, or CNS, made up of the brain and the spinal cord that extends from it.
What is the composition of the brain?
The average adult’s brain weighs roughly 3 pounds and is 60 percent fat. Water, protein, carbs, and salts make up the remaining 40% of the body. The brain is not a muscle in and of itself. It made up of blood vessels, nerves, neurons, and glial cells.
What is the difference between grey and white matter?
The central nervous system has two distinct regions: grey and white matter. Gray matter refers to the darker, outer part of the brain, whereas white matter refers to the lighter, interior part. This sequence inverted in the spinal cord, with a white matter on the exterior and grey matter on the inside.
Gray matter generally made up of neuron somas (round central cell bodies), while white matter mostly made up of myelin-wrapped axons (long stems that connect neurons) (a protective coating). On other scans, the two show as discrete shades due to the varied composition of neuron sections.
Each zone has a distinct function. Gray matter is in charge of processing and interpreting data, whereas white matter is in charge of transmitting that data to other regions of the nervous system.
What is the function of the brain?
Chemical and electrical impulses are sent and received by the brain throughout the body. Different signals govern various processes, which your brain decodes. Some cause you to feel fatigued, while others cause you to feel discomfort.
Some messages preserved in the brain, while others sent to distant extremities via the spine and the body’s enormous network of nerves. The central nervous system relies on billions of neurons to accomplish this (nerve cells).
The Functions of the Brain’s Major Components
The cerebrum, brainstem, and cerebellum are the three parts of the brain that can split to a high degree.
Gray matter (the cerebral cortex) and white matter make up the cerebrum (front of the brain). The cerebrum, the largest region of the brain, controls temperature and initiates and directs movement. Speech, judgment, thinking and reasoning, problem-solving, emotions, and learning are all enabled by other parts of the cerebrum. Vision, hearing, touch, and other senses are all involved in other processes.
The exterior grey matter that covers the cerebrum known as the cortex, which is Latin for “bark.” Because of its folds, the cortex has a huge surface area and accounts for almost half of the brain’s weight.
The cerebral cortex is split into two hemispheres or halves. It has ridges (gyri) and folds on it (sulci).
Also, the two parts meet in a huge, deep sulcus that extends from the front to the back of the head (the interhemispheric fissure, also known as the medial longitudinal fissure).
The left half of the brain controls the left side of the body, whereas the right half controls the right side.
The corpus callosum is a huge, C-shaped structure of white matter and nerve connections that connects the two sides of the brain. The corpus callosum is located in the cerebrum’s core.
The cerebrum is connected to the spinal cord by the brainstem (middle of the brain). The midbrain, pons, and medulla are all part of the brainstem.
- Midbrain. The midbrain (also known as the mesencephalon) is a complex structure that contains a variety of neuron clusters (nuclei and colliculi), neural pathways, and other structures. These traits aid a variety of activities, ranging from hearing and movement to calculating responses and adjusting to changes in the environment the substantia nigra, a dopamine-rich area damaged by Parkinson’s disease and part of the basal ganglia, which controls movement and coordination, is also located in the midbrain.
- Pons. Four of the 12 cranial nerves originate in the pons, allowing for a variety of functions such as tear formation, chewing, blinking, concentrating vision, balance, hearing, and facial expression. The pons is the link between the midbrain and the medulla, and named from the Latin word for “bridge.”
- Medulla. The medulla is where the brain meets the spinal cord at the bottom of the brainstem. The survival of the medulla is crucial. The medulla controls a wide range of body functions, including heart rate, respiration, blood flow, and oxygen and carbon dioxide levels. Sneezing, vomiting, coughing, and swallowing are all reflexive movements produced by the medulla.
The spinal cord runs from the bottom of the medulla to the bottom of the skull, passing through a huge hole. The spinal cord, which supported by the vertebrae, transmits messages to and from the brain and the rest of the body.
The cerebellum (sometimes known as the “little brain”) is a fist-sized part of the brain positioned behind the ears, behind the temporal and occipital lobes, and above the brainstem. It has two hemispheres, just like the cerebral cortex. The inner part communicates with the cerebral cortex, while the outer section contains neurons, its job is to keep posture, balance, and equilibrium by coordinating voluntary muscle movements. The cerebellum’s responsibilities in thought, emotions, and social interaction, as well as its possible participation in addiction, autism, and schizophrenia, are being investigated in new studies.
Meninges are the protective coverings that surround the brain.
The meninges are three layers of protective covering that surround the brain and spinal cord.
- The dura mater, the outermost layer, is thick and robust. It is made up of two layers: The dura mater’s periosteal layer lines the inner dome of the skull (cranium), whereas the meningeal layer lies beneath it. Veins and arteries that feed blood to the brain can travel through the spaces between the layers.
- The arachnoid mater is a web-like layer of connective tissue that lacks nerves and blood arteries. The cerebrospinal fluid, or CSF, is found underneath the arachnoid mater. The entire central nervous system (brain and spinal cord) is cushioned by this fluid, which circulates continuously to eliminate pollutants.
- The pia mater is a thin membrane that embraces and follows the curves of the brain’s surface. Veins and arteries abound in the pia mater.
The Controlled Functions of the Brain’s Lobes
The frontal, parietal, temporal, and occipital lobes are the four portions of each cerebral hemisphere (parts of the cerebrum). Each lobe is in charge of a different function.
- The frontal lobe is the most important part of the brain. The frontal lobe is the brain’s largest lobe, located in the front of the head, and involved in personality traits, decision-making, and movement. Parts of the frontal lobe frequently involved in recognizing smells. Broca’s region, which connected with speech skills, is located in the frontal brain.
- The parietal lobe is a part of the brain that is responsible for memory, and located in the middle of the brain, aids in object recognition and spatial relationships (where one’s body compared to objects around them). The parietal lobe is also involved in pain and touch perception in the body. Wernicke’s region, which helps the brain perceive spoken language, is located in the parietal lobe.
- The occipital lobe is a part of the brain that is located behind the ear The occipital lobe, located in the back of the brain, is responsible for vision.
- The temporal lobe is the part of the brain that deals with time. Short-term memory, speaking, musical rhythm, and some degree of smell identification are all aided by the temporal lobes on the sides of the brain.
The Brain’s Deeper Structures
Pituitary Gland (Pituitary Gland)
The pituitary gland, sometimes known as the “master gland,” is a pea-sized organ located deep within the brain behind the bridge of the nose.
The pituitary gland regulates the flow of hormones from the thyroid, adrenals, ovaries, and testicles,
as well as the function of other glands in the body. Through its stalk and blood supply, it gets chemical signals from the hypothalamus.
The hypothalamus, which situated above the pituitary gland, provides chemical instructions to it that regulate its function. It controls appetite and thirst, regulates body temperature, and plays a function in some elements of memory and emotion.
Amygdala is a little almond-shaped structure found beneath each half (hemisphere) of the brain. The amygdalae, which part of the limbic system, govern emotion and memory and linked to the brain’s reward system, stress, and the “fight or flight” reaction when faced with a threat.
The hippocampus is a curved seahorse-shaped organ on the underside of each temporal lobe that part of the hippocampal formation, a bigger structure. It aids memory, learning, navigation, and spatial awareness. It collects data from the cerebral cortex and could involve in Alzheimer’s disease.
Gland of the Pineal
The pineal gland finds deep within the brain and connected to the top of the third ventricle by a stalk. The pineal gland governs circadian rhythms and the sleep-wake cycle by secreting melatonin in response to light and dark.
Cerebrospinal Fluid and Ventricles
Four open zones with passageways run deep within the brain. They also open into the central spinal canal and the space underneath the meninges’ arachnoid layer.
The ventricles produce cerebrospinal fluid (CSF), a watery fluid that circulates between the meninges and in and around the ventricles and spinal cord. CSF is a fluid that surrounds and cushions the spinal cord and brain, removes waste and pollutants, and transports nutrients.
The Brain’s Blood Supply
The vertebral arteries and the carotid arteries are two sets of blood vessels that carry blood and oxygen to the brain.
When you touch the area with your fingertips, you can feel your pulse in the external carotid arteries,
which run up the sides of your neck. Blood circulated to the front region of the brain by the internal carotid arteries, which branch into the skull.
The vertebral arteries go up the spine and into the skull, where they combine at the brainstem to form the basilar artery, which delivers blood to the brain’s back half.
The Willis circle, a loop of blood vessels near the bottom of the brain that connects major arteries,
circulates blood from the front to the rear of the brain and aids communication between the arterial systems.
Nerves of the skull
There are 12 nerves called cranial nerves that go through the cranium (the dome of the skull):
- The first cranial nerve is the olfactory nerve, which controls your sense of smell.
- The optic nerve is the second cranial nerve, and it controls vision.
- The oculomotor nerve branches out from the area in the brainstem where the midbrain meets the pons and mediates pupil response and other eye motions.
- The trochlear nerve is a cranial nerve that regulates eye muscles. It emerges from the back of the brainstem’s midbrain region.
- The trigeminal nerve, which has both sensory and motor functions, is the largest and most complex of the cranial nerves. It begins in the pons and transmits sensation to the brain from the scalp, teeth, jaw, sinuses, and various regions of the mouth and face, as well as allowing the function of chewing muscles.
- The abducens nerve is a cranial nerve that innervates some of the eye muscles.
- The facial nerve facilitates facial movement, taste, glandular function, and other activities.
- The vestibulocochlear nerve is a cranial nerve that helps with balance and hearing.
- The glossopharyngeal nerve is a cranial nerve that controls taste, ear, and throat movement, among other things.
- The vagus nerve governs motor activity in the heart, throat, and digestive system and allows feeling around the ear and in the digestive system.
- The accessory nerve, also known as the cranial nerve 11, is responsible for the innervation of particular muscles in the head, neck, and shoulder.
- The hypoglossal nerve is a cranial nerve that provides motor activity to the tongue.
- The first two cranial nerves come from the cerebrum, whereas the following ten emerges from the brainstem, which divided into three sections: the midbrain, pons, and medulla.