The nervous system

The Anatomy and Physiology of

The Nervous System

Organs

CNS:

Brain

Spinal Cord

PNS:

Nerves

Brain

It is one of the largest organs in the body, and coordinates most body activities.

It is the center for all thought, memory, judgment, and emotion.

Each part of the brain is responsible for controlling different body functions, such as temperature regulation and breathing.

Cerebrum

It is the largest section of the brain

It is located in the upper portion of the brain and is the area that processes thoughts, judgment, memory, problem solving, and language.

The outer layer of the cerebrum is the cerebral cortex, which is composed of folds of gray matter.

The cerebrum is subdivided into the left and right halves called cerebral hemispheres. Each hemisphere has 4 lobes.

Lobes of Cerebrum

Lobes of Cerebrum

1. Frontal lobe: Most anterior portion of the cerebrum, controls motor function, personality, and speech

2. Parietal lobe: The most superior portion of the cerebrum, receives and interprets nerve impulses from sensory receptors and interprets language.

3. Occipital lobe: The most posterior portion of the cerebrum, controls vision.

4. Temporal lobe: The left and right lateral portion of the cerebrum, controls hearing and smell

Cerebellum

Second largest portion of the brain

Located beneath the posterior part of the cerebrum

Aids in coordinating voluntary body movements and maintaining balance and equilibrium

Refines the muscular movement that is initiated in the cerebrum

Brain Stem

Midbrain—acts as a pathway for impulses to be conducted between the brain and the spinal cord.

Pons — means bridge—connects the cerebellum to the rest of the brain.

Medulla oblongata—most inferior positioned portion of the brain; it connects the brain to the spinal cord.

Spinal Cord

Runs through the vertebral canal

Extends from foramen magnum to 2nd lumbar vertebra

Regions

Cervical

Thoracic

Lumbar

Sacral

Coccygeal

Gives rise to 31 pairs of spinal nerves - all are mixed nerves

Meninges

Dura mater: outermost layer; continuous with epineurium of the spinal nerves

Arachnoid mater: thin and wispy

Pia mater: bound tightly to surface

Nerves

Nerves

Neuron

Synapse