NERVOUS SYSTEM IN HUMANS Grade 12 Exercise scienceKevin Lee

Table of Contents

The 2 types of Nervous system in humans Central Nervous System Peripheral nervous system

The relative of peripheral nervous system Nervous tissues

Neurons Glial cells

How it functions?

Central Nervous System The central nervous

system (CNS) is the largest part of the nervous system, and includes the brain and spinal cord.

The spinal cavity holds and protects the spinal cord, while the head contains and protects the brain.

Peripheral nervous system The bodies of the

nerve cells lie in the CNS, either in the brain or the spinal cord

The longer of the cellular processes of these cells, known as axons, extend through the limbs and the flesh of the torso

Peripheral nervous system Somatic

nervous system

Automatic nervous system

Sympathetic division

Enteric division

Parasympathetic division

Nervous tissue

Nervous tissue is composed of two main cell types: neurons and glial cells.

-Neurons transmit nerve messages.

-Glial cells are in direct contact with neurons and often surround them.

Neurons

The neuron is the functional unit of the nervous system. While variable in size and shape, all neurons have three parts.

Dendrites receive information from another cell and transmit the message to the cell body.

The cell body contains the nucleus, mitochondria and other organelles typical of eukaryotic cells. The axon conducts messages away from the cell body.

Glial cells Glial cells provide support and

protection for neurons The four main functions of glial

cells are to surround neurons and hold them in place, to supply nutrients and oxygen to neurons, to insulate one neuron from another

To destroy pathogens and remove dead neurons. They also modulate neurotransmission

Sensor in put

Integration (brain analyze)

Motor output (react)

Messages to Neurons

Messages is received by the dendrites Axon creates signal usually a chemical

messenger called a neurotransmitter Signal travels to axons Message is transferred to connected to

neuron via synaptic terminal