The Nervous System. Types Central Nervous System (CNS)Peripheral Nervous System (PNS)
The nervous system
description
Transcript of The nervous system
The nervous system
Nervous and endocrine systemsThe nervous and endocrine glands sys-
tems interact to control and coordi-nate the body’s
-responses to change in its environ-ment
-growth & development-reproduction
A. Nervous system: Nervous con-trol depends mainly on the func-tioning of neurons (nerve cells).
1. Stimulus: a change in the external or internal environment which initi-ates and impulse.
examples: vision, smell, taste, pres-sure, temperature, pain, equilibrium.
• A demonstration
2. Impulse: an electro-chemical charge generated along a neuron.
• Electro-inside neuron• Chemical: between neurons
http://en.wikipedia.org/wiki/Action_potential
http://ffden-2.phys.uaf.edu/212_fall2003.web.dir/Casey_Adamson/Personal%20Web%20Page.htm
3. Receptors: structures specialized to detect certain stimuli
4. Response: a reaction to a stimulus
http://meredithbond.com/blog/stimulus-and-response/
5. Neuron: the basic cellular unit of the nervous system (specially designed for the transmission of impulses.) Our brain has millions of neurons.
Neuron
Neurona. Terminal branches: ends of axons
that secrete neurotransmitters.b. Synapse: gap between adjacent
neurons (terminal branches of one neuron and the dendrites of the next) or the gap between neuron and ef -fector.
6. neurotransmitter• Neurotransmitter: chemical sub-
stance which starts the transmission of the nervous impulse (Acetyl-choline degraded by cholinesterase)
Neurotransmitter con’t• Acetylcholine is the most common
neurotransmitter. • Dopamine is another neurotransmit-
ter that brings pleasure.
http://www.muscular-dystrophy.org/research/news/3262_study_compares_two_treatments_for_myasthenia_gravis
Why do you think the nervous sys-tem is important?
How do neurotransmitters work to trans-mit the nervous impulse in humans?
1. Nervous impulse travels down an axon to the tips of a terminal branch.
2. The terminal branch secretes neuro-transmitter into the synapse gap.
3. The neurotransmitter travels to the next neuron and causes depolarization of that neuron-thus a new nervous im-pulse is started in the next neuron.
videoSynapse Structure and Function• http://www.youtube.com/watch?v=r
Wrnz-CiM7A
• Neurons may release chemicals to stimulate each other. An example of a muscle being stimulated by a neu-ron appears after the reflex path pic-tured in number four in the diagram.
• More complex animals have a central nervous system which includes a brain and a nerve cord (spinal cord).
• Brain: a large mass of neurons lo-cated in the cranial cavity—contains three major divisions.
• Cerebrum: center for voluntary activity; in-terprets sensory impulses, initiates some motor activities, and responsible for mem-ory, thinking, and reasoning.
• Cerebellum: coordinates motor activities and aids in maintaining balance.
• Medulla: controls involuntary activities such as breathing, heartbeat, blood pres-sure and peristalsis ( is part of the brain stem),
Video The nervous systemhttp://www.youtube.com/watch?v=sjyI4CmBOA0
Spinal cord: lies within, and is pro-tected by, the vertebrae of the spinal column.
http://www.quantumday.com/2012/06/walking-again-after-spinal-cord-injury.html
-- is continuous with the brain coordi-nates activities between the brain and other body structures (bridge be-tween the brain and the peripheral nervous system)
-- it is also a center for reflex actions.
Peripheral nervous system-- is located outside the central ner-
vous system and consists of the nerves extending throughout the body.
http://www.umm.edu/imagepages/8679.htm
Peripheral nervous system1) somatic: voluntary control2) automatic: involuntary