The central nervous system (CNS) is one of the two main components of the nervous system, the other being the peripheral nervous system (PNS).
The CNS consists of the brain and spinal cord, which are protected by various layers of connective tissue and bone (the skull and vertebral column).
The main functions of the CNS are to receive, process, and transmit information from the rest of the body.
It plays a crucial role in controlling and coordinating various bodily functions, such as movement, sensation, cognition, memory, and emotion.
The brain is divided into several regions, each responsible for specific functions:
1. Cerebrum:
The largest part of the brain, it is responsible for higher cognitive functions like thought, memory, language, and learning.
The cerebrum is further divided into two hemispheres (left and right) and four lobes (frontal, parietal, temporal, and occipital).
2. Cerebellum:
Located at the back of the brain, the cerebellum is responsible for coordinating muscle movements, maintaining balance, and processing information related to movement.
3. Brainstem:
Connecting the brain to the spinal cord, the brainstem is responsible for basic life-sustaining functions, such as breathing, heart rate, and blood pressure.
It also plays a role in sleep and arousal.
The spinal cord, a long bundle of nerve fibers, runs from the brainstem to the lower back. It serves as a conduit for signals between the brain and the rest of the body.
The spinal cord is also responsible for certain reflexes that do not require input from the brain.
Meninges
The meninges are three protective layers of connective tissue that surround and protect the central nervous system (CNS), which includes the brain and spinal cord.
These layers serve several important functions, such as providing physical protection, supporting the CNS, and containing the cerebrospinal fluid (CSF) that cushions the brain and spinal cord.
There are three layers of meninges, from the outermost to the innermost:
1. Dura mater:
The tough, outermost layer that provides strength and durability, composed of two sub-layers (periosteal and meningeal) and responsible for creating protective folds in the brain.
2. Arachnoid mater:
The middle, web-like layer that contains the cerebrospinal fluid-filled subarachnoid space, arachnoid trabeculae for support, and arachnoid granulations for CSF reabsorption.
3. Pia mater:
The delicate, innermost layer that closely follows the contours of the CNS, supplies blood to neural tissue, and contributes to the production of cerebrospinal fluid via the choroid plexus.