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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