ANATOMY NERVOUS SYSTEM OVERVIEW

Nervous System  The nervous system of the human is the most highly organized system of the body.  The overall function of the nervous system is to control and coordinate the human body.

NERVOUS SYSTEM  The nervous system consists of the brain, the spinal cord and the nerves.  The functional, structural unit of the nervous system is the nerve cell called the neuron.

Neurons  The neuron has extensions of various lengths from its cell body called Dendrites and Axons.  Each cell body may have many dendrites, but only one axon.

Neurons  The Dendrites receive an impulse, pass it to the cell body, then to the axon where it is passed on to muscle, glands or another neuron.

Neurons  There are three types of neurons: Sensory Sensory Motor or connecting Motor or connecting Associative Associative Neurons do not connect with each other but send impulses over spaces called synapses.Neurons do not connect with each other but send impulses over spaces called synapses.

Divisions of the nervous system  The central nervous system includes the brain and the spinal cord. The nerves of the spinal cord and brain do not have the special coating called neurilemma which allows nerve cells to repair. (paralysis or death may occur)

Nervous system divisions  The peripheral nervous system is composed of all the nerves extending from the brain (cranial nerves) and spinal cord. (spinal nerves)

Peripheral system  The peripheral nervous system connects the central nervous system to various body structures. Cranial nerves carry impulses to and from the brain, spinal nerves carry impulses to and from the spinal cord.

Autonomic system  The autonomic system controls the involuntary or automatic activities of vital internal organs, such as the heart, blood vessels and organs of digestion.

The brain  The brain is a complex mass of tissue protected by the bony structure of the cranium. The brain is further protected by membrane coverings called the meninges and cerebrospinal fluid.

The brain  There are three major parts of the brain. The cerebrum The cerebellum The brain stem

The Cerebrum  The cerebrum is the largest part of the brain, divided into two hemispheres. Each hemisphere is divided into four lobes. The frontal The frontal The parietal The parietal The occipital The occipital The temporal The temporal

Lobes of the brain  Each lobe of the cerebral hemispheres control specific functions. #1 The frontal lobe: #1 The frontal lobe: The cells in the right half control the voluntary motor movements of the left side of the body, and the left side controls the right side. The frontal lobe also controls speech.The cells in the right half control the voluntary motor movements of the left side of the body, and the left side controls the right side. The frontal lobe also controls speech.

Lobes of the brain #2 The parietal lobe: #2 The parietal lobe: This area receives and interprets nerve impulses from the sensory receptors for pain, touch, heat and cold. The parietal lobe also helps determine distance, size and shape.This area receives and interprets nerve impulses from the sensory receptors for pain, touch, heat and cold. The parietal lobe also helps determine distance, size and shape. #3 The occipital lobe: #3 The occipital lobe: Located over the back of the brain over the cerebellum contains the visual area controlling eyesight.Located over the back of the brain over the cerebellum contains the visual area controlling eyesight.

Lobes of the brain #4 The temporal: #4 The temporal: Located on the sides of the brain, the temporal lobe contains areas which control auditory hearing and olfactory smell.Located on the sides of the brain, the temporal lobe contains areas which control auditory hearing and olfactory smell.

The Cerebrum  The outer layer of the cerebrum is gray nerve tissue called the cerebral cortex. It is formed with deep folds causing elevated portions called convolutions and furrows and groves called fissures.

The cerebrum  This folding (convolutions and fissures) increase the surface area of the cerebral cortex. The cerebral cortex controls thoughts, judgment, memory, reasoning, and will power.

Under the gray matter  Beneath the gray matter of the cerebral cortex lies the thalamus, and hypothalamus. The thalamus acts as a relay center for sensory impulses to the cerebral cortex. The hypothalamus controls temperature, sleep, water balance and chemical activities.

The cerebellum  This part of the brain located at the back and lower part of the brain coordinates the muscular movements of the body, such as balance in walking and sitting.

The brain stem  The brain stem is made up of three parts. The midbrain, the pons and the medulla. This part of the brain controls respiration, heart and blood vessels.

The Spinal cord  The spinal cord is made up of nerve fibers protected by the bony structure of the vertebra and spinal fluid. The function of the spinal cord is to serve as a pathway to and from the brain.

Diseases  Nerve cells often do not repair themselves so damage can cause permanent loss of function. Damage to the brain and spinal cord by force and injury may result in death or paralysis.

Diseases  Other disease include: Parkinson's Seizures Multiple sclerosis Cerebral vascular accident (CVA or stroke) Infections and tumors also may affect the nervous system.

Vocabulary Words