Download Nervous System Notes

The Nervous System
What is the structure of the
nervous system?
•
Neurons
•
specialized cells that:
•
gather information about your environment
•
interpret information
•
help you react to information
•
3 regions of the neurons:
•
dendrites - receive signals (impluses) from
other neurons
•
cell body - nucleus of the neuron
•
axon - carries nerve impulses from cell
body to other neurons and muscles
What are the 3 kinds of
neurons?
•
sensory neurons
•
•
send impulses from receptors in the skin and
sense organs to the brain and spinal cord
interneurons - located in the brain and spinal cord
•
carry impulse from sensory neurons to motor
neurons
•
motor neurons
•
carry impulses away from brain and spinal
cord
•
impulses go to muscles or glands, which
respond
What is the reflex arc?
•
nerve pathway that consists of a sensory neuron,
an interneuron, and a motor neuron
What is a nerve impulse?
•
electrical charge that travels the length of a neuron
•
caused by a stimulus
•
results in a response
What is a synapse?
•
small gap between the axon of one neuron and the
dendrite of another
•
the more a synapse is stimulated, the stronger the
connection between the neurons becomes
•
if synapses are not stimulated, the connection
never forms or it goes away
1. Cerebellum
•
Controls balance and muscle coordination
2. Spinal Cord
•
Connects the brain to the peripheral nervous
system
3. Medulla Oblongata
•
Controls heart rate, blood pressure and respiration
4. Pons
•
controls sleep, swallowing, eye movement and
facial expression
5. Midbrain
•
involved in vision, hearing and temperature
regulation
6. Fornix
•
Involved in the formation of memories and recall
7. Pituitary Gland
•
produces hormones
8. Optic chiasma
•
point where nerves from the two eyes come
together
9. Olfactory Bulb
•
controls smell
10. Hypothalamus
•
involved in control of body temperature, appetite
and sleep
11. Corpus callosum
•
Connects the two hemispheres of the brain
12. Thalamus
•
sensory relay center
What are your senses?
•
Taste and smell
•
senses of taste and smell are stimulated by
chemicals and often function together
•
special receptors located in the nose send
information to the olfactory bulb
•
taste buds located on the tongue detect sweet,
sour, salty, bitter and unami
•
Sight
•
light enters the eye through the cornea
•
cornea helps to focus light through the pupil
•
pupil is surrounded by the iris
•
behind the iris is the lens
•
lens projects image on to the retina
•
retina is made of rods and cones
•
Hearing and Balance
•
ears detect volume and frequency of sound
•
canals in the inner ear control your sense of balance
•
hearing
•
sound waves cause the eardrum to vibrate
•
vibrations travel through 3 bones in the middle
ear
•
auditory nerves carry messages to the brain
•
Balance
•
3 semicircular canals in the inner ear
transmit information about body
position to the brain
•
fluid in the canals determines the
position of the head