The Structure, Function and Main Disorders of the Nervous System

I. Structure of the Nervous System:

The nervous system is divided into the central nervous system (CNS), which includes the brain and the spinal cord, and the peripheral nervous system (PNS), which includes all other neural elements.
The PNS can be further divided into the autonomic nervous system (regulates involuntary body functions like breathing, heart rate etc.) and the somatic nervous system (controls voluntary activities).

II. Functions of the Nervous System:

The primary function of the nervous system is to control and coordinate the body’s response to changes in its internal and external environments.
The nervous system communicates information through nerve impulses from one part of the body to another.
The brain serves integrating these signals and stores information for future use.

III. Main Disorders of the Nervous System:

Alzheimer’s Disease – A progressive disease that destroys memory and other important mental functions.
Parkinson’s Disease – A degenerative disorder of the central nervous system, marked especially by tremor, muscle rigidity and slow, imprecise movement.
Stroke – A condition in which the brain cells suddenly die because of a lack of oxygen which is often caused by blockage of a blood vessel supplying the brain or a hemorrhage.
Multiple Sclerosis - A chronic, often disabling disease that attacks the central nervous system, it can cause symptoms such as numbness in the limbs, paralysis or loss of vision.
Epilepsy – A group of neurological disorders characterized by epileptic seizures.
Migraine – A type of headache, could be associated with symptoms like nausea, dizziness, sensitivity to light and sound.

Remember, when discussing the structure, function, and main disorders of the nervous system, one must always seek to link these key components together. The structure allows the function, and when the structure is altered (whether through injury, disease, etc.), this can lead to the disorders we observe.