Nervous System
The nervous system is made up of the central nervous system and the peripheral nervous system:
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The brain and the spinal cord are the central nervous system.
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The nerves that go through the whole body make up the peripheral nervous system.
Both the brain and the spinal cord are protected by bone: the brain by the bones of the skull, and the spinal cord by a set of ring-shaped bones called vertebrae.
They're both cushioned by layers of membranes called meninges and a special fluid called cerebrospinal fluid. This fluid helps protect the nerve tissue, keep it healthy, and remove waste products.
The brain is made up of three main sections: the forebrain, the midbrain, and the hindbrain.
The Forebrain
The forebrain is the largest and most complex part of the brain. It consists of the cerebrum — the area with all the folds and grooves typically seen in pictures of the brain — as well as some other structures under it.
The cerebrum contains the information that essentially makes us who we are: our intelligence, memory, personality, emotion, speech, and ability to feel and move.
Specific areas of the cerebrum are in charge of processing these different types of information. These are called lobes, and there are four of them: the frontal, parietal, temporal, and occipital lobes.
The cerebrum has right and left halves, called hemispheres. They're connected in the middle by a band of nerve fibers (the corpus callosum) that lets them communicate. These halves may look like mirror images of each other, but many scientists believe they have different functions:
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The left side is considered the logical, analytical, objective side.
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The right side is thought to be more intuitive, creative, and subjective.
The outer layer of the cerebrum is called the cortex (also known as "gray matter"). Information collected by the five senses comes into the brain to the cortex. This information is then directed to other parts of the nervous system for further processing.
For example, when you touch the hot stove, not only does a message go out to move your hand but one also goes to another part of the brain to help you remember not to do that again.
In the inner part of the forebrain sits the thalamus, hypothalamus, and pituitary gland :
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The thalamus carries messages from the sensory organs like the eyes, ears, nose, and fingers to the cortex.
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The hypothalamus controls the pulse, thirst, appetite, sleep patterns, and other processes in our bodies that happen automatically.
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The hypothalamus also controls the pituitary gland, which makes the hormones that control growth, metabolism, water and mineral balance, sexual maturity, and response to stress.
The Midbrain
The midbrain, underneath the middle of the forebrain, acts as a master coordinator for all the messages going in and out of the brain to the spinal cord.
The Hindbrain
The hindbrain sits underneath the back end of the cerebrum. It consists of the cerebellum, pons, and medulla. The cerebellum — also called the "little brain" because it looks like a small version of the cerebrum — is responsible for balance, movement, and coordination.
The pons and the medulla, along with the midbrain, are often called the brainstem. The brainstem takes in, sends out, and coordinates the brain's messages. It also controls many of the body's automatic functions, like breathing, heart rate, blood pressure, swallowing, digestion, and blinking.
Layer of Brain
Subdural means situated or occurring between the dura mater and the arachnoid membrane of the brain and spinal cord.
A subdural tap is a medical procedure that involves the removal of excessive fluid build-up in the subdural space, a condition caused by a disease or significant trauma to the head. In infants, the procedure can be performed by inserting a fine hollow needle through the fontanelle or the suture.
A fontanelle (fontanel) is a soft spot between the five major bones of an infant’s skull (2 frontal bones, 2 parietal bones, and an occipital bone). A soft membrane called a suture connects these bones. Sutures allow the bones to move to accommodate the growth of the skull.
In the past, a subdural tap was usually performed as a diagnostic procedure to determine the cause of an acute or chronic build up of subdural fluids that result in an increase in intracranial pressure. It could also be performed to remove an excessive amount of fluids, such as cerebral spinal fluid (CSF) and/or blood.
Normal Suture of the Newborn
