NERVOUS SYSTEM

NERVOUS SYSTEM
Nervous system- constitutes a network of communication channels that spreads to every part of the body.
- composed of two interrelated systems.

2 types of nervous system
Central nervous system- composed the brain and the spinal cord where the information processed and decisions are made.
Peripheral nervous system- it consists of nerves.
1. Somatic nervous system- consists of both sensory and motor neurons. It controls voluntary movements.
2. Autonomic nervous system- controls the involuntary movements.
Ex. Respiration, circulation, heart intestines, blood vessels and glands.
Basic elements of nervous system
Neuron- basic unit of the nervous system. It is a special nerve tissue which serves a special function.
3 distinct parts of neuron
a. Dendrites
b. The cell body
c. Axon
Dendrites- are found at the end of the cell body. They are fine and tiny hairline structures. It looks like a branch of tree.
Axon-distinct part of the neuron which is found at its other end. Only one axon in neuron.
Axon terminal/end brush- an elongated with one or more in formations at it far ends.
Synaptic transmission- the process of transmitting information from neuron to neuron.
2 types of neurons
(Classified according to length and functions)
a. Long conducting neurons
b. Correlating neurons
Long conducting neurons- has long single dendrites. Pathways of the central nervous system.
Correlating neurons- has short dendrites and axon. Provide many connections and pathways for neural excitations.
Neurons classified as according to their functions in nervous system
a. Sensory- environmental stimuli and information about environments.
b. Association neurons- found between sensory and motor neurons. It conveys impulses from sensory to motor neurons.
c. Motor/efferent neurons- control activities of muscles and glands. It carries nerve impulses.