nervous system: part i. the nervous system your body’s communication’s network & control...
TRANSCRIPT
The Nervous System Your body’s communication’s network &
control center Peripheral Nervous System (PNS)-
gathers info from inside & outside the body
Central Nervous System (CNS)-receives this info & initiates a response-composed of the brain & spinal cord
Messengers & receivers of these transmissions are NEURONS (nerve cell)
Three Types of Neurons Sensory-carry from
sense receptors to CNS (5 senses)
Motor-carry signals from CNS to muscles or glands
Interneurons-carry electrical connections within the CNS
Functions of Neurons Cell body-contains nucleus & cell
membrane Dendrites-branching projections of the cell
body, carry impulses into the cell. Axon-Threadlike extension carries impulses
to & from the cell, at the end of axon is the axon terminal
Myelin Sheath-Insulates the axon & speeds up transmission of the impulses
Synapse-point of contact at which impulses are passed from one cell to another
Let’s draw neurons! Look at the drawing on
page 517 of your health book.
You will need 4 different colors markers/pencils, for the:
cell body dendrites axon/terminal synapse
Draw your neuron on a piece of paper
color and label the parts
Right Brain--- Left Brain
Sitting at your desk, lift your right foot off the floor and make clockwise circles
Now, while doing this, draw the number "6" in the air with your right hand. [Your foot will likely change direction, and there's nothing you can actually do about it.]
Reflex Action (Unconscious) If the safety of our body
requires a very quick response, the signals may pass directly to a motor neuron for instant, unthinking action. This is a reflex action. Signals sent via the spinal cord
List as many examples of a reflex action as you can:
http://www.bbc.co.uk/schools/gcsebitesize/biology/humansasorganisms/4nervoussystemrev4.shtml
Voluntary Actions (Conscious Act) Impulses passed via the
brain What is the chain of
events that happens from the instant you hear the phone ring until you pick up the phone?
Every time a stimulus—such as a ringing telephone—is detected, the body's three kinds of neurons send a nerve impulse through the nervous system.
Nerve Impulse Activity In groups put the following path
of a nerve impulse in the correct order:
1.The nerve impulses pass to interneurons in the brain.
2.Receptors in your ear pick the sound of a ringing phone
3.Muscles in the arm carry out the response and you reach to pick up the phone
4. Impulses travel along motor neurons to the muscles
5. Receptors trigger nerve impulses in sensory neurons
6. Your brain interprets the impulses from many interneurons and you realize the phone is ringing. Your brain also decides that you should answer the phone.
Correct order… 2. Receptors in your ear pick the sound of a
ringing phone 5. Receptors trigger nerve impulses in sensory
neurons 1. The nerve impulses pass to interneurons in
the brain. 6. Your brain interprets the impulses from
many interneurons and you realize the phone is ringing. Your brain also decides that you should answer the phone.
4. Impulses travel along motor neurons to the muscles
3. Muscles in the arm carry out the response and you reach to pick up the phone
The Brain
Largest, most complex part of the nervous system
Weighs 3 pounds, contains billions of neurons
Without oxygen it can only last 4-5 minutes
Cerebrum
Forms our intellect & personality Divided into two hemispheres Left-language & logic Right-imagination & emotional
responses Does not fully develop until late
teens or early-mid 20s!!!