Biology - Chapter 8.1 - Outline of the Nervous System

What viral disease affects the nerve cells of the spinal cord?

Poliomyelitis

Brain

Principal organ of the nervous system.

Blood-brain barrier

Tightly sealed capillary walls that protect the central nervous system from being permanently damaged every time you get sick.

What is the function of the dendrites?

Receives the nerve impulses from other neurons and conducts them toward the cell body.

What is the function of the axon?

Relays nerve impulses from the cell body to other neurons.

What are the three broad categories of neurons?

Sensory neurons Motor neurons Interneurons

What organs belong to the peripheral nervous system?

The nerves that branch from the brain and spinal cord (cranial nerves and spinal nerves).

Ganglion

A mass of cell bodies

What is the difference between gray matter and white matter?

*Gray matter* consists largely of the cell bodies of neurons and is gray because these bodies lack myelin. *White matter* is composed of axons and glial cells that are white because of their myelin content.

Poliomyelitis

A serious disease that attacks the spinal cord. It is caused by a virus which enters the motor neurons of the spinal cord and destroys some of them.

Coma

A state of prolonged unconsciousness, serious brain damage can result

Spinal cord

A thick bundle of nerve fibers located within the spinal cavity.

Meninges

A triple layer of protective tissues covering the spinal cord and brain. Outer layer - dura mater One of the strongest tissues of the body, serves as a flexible protective layer. Middle layer - arachnoid Thin fibers like the fibers of a spider's web, forming an intricate three-dimensional network around the brain. Inner layer - pia mater

Neurons

Actual nerve cells

Myelin

Cell bodies of neurons, white specialized covering

What organs belong to the central nervous system?

Brain and spinal cord.

Nerves

Bundles of nerve fibers (axons) branching from the brain and spinal cord and connecting the central nervous system to the extremities of the body.

Identify the main parts of a neuron.

Cell body, dendrites and axon.

Glial cells

Cells that support and insulate nerve tissue

What are the main divisions of the nervous system?

Central nervous system and peripheral nervous system.

What is the function of the cell body?

Contains the cell's nucleus and most of the cytoplasm.

Cranial nerves

12 pairs of nerves that branch directly from the brain stem and transmit nerve signals to and from the eyes, ears, mouth, face and scalp.

Spinal nerves

31 pairs of nerves, which branch from the spinal cord and extend out of the spinal cavity between the vertebrae. They transmit nerve signals to and from the rest of the body.

Cerebrospinal fluid

A clear fluid that circulates through the fibers of the arachnoid, cushions the brain when bump head

Meningitis

A disease caused by invading micro-organisms enter the nerve tissue and infect the meninges.

Nerve center

A group of cell bodies in the brain or spinal cord

Plexus

A group of ganglion forming a large nerve mass

Explain how the sympathetic and parasympathetic divisions of the autonomic nervous system work together to regulate body activities.

Answers may include some of the following ideas: 1. The two systems are complementary. Generally, the sympathetic division stimulates organs when you are active, in danger, or under stress, while the parasympathetic division stimulates organs while you rest. 2. The sympathetic division causes heartbeat and breathing rates to increase and inhibits the activity of the digestive system. The parasympathetic division shows the heartbeat and breathing rates and increases the activity of the digestive system.