Synapses and
Reflex Action
Synapse
• Neurons are not
continuous
• Synapse is “The junction
across which a nerve
impulse passes from an
axon terminal to a
neuron, muscle cell or
gland”
• Two types of Synapses:
o Excitatory
o Inhibitory
Reflex Action
• In Groups of 3.
• 2 people face each other, looking at each other
• The third person stands off to the side.
• Anytime from 1 Sec till 10 Seconds the third person
will clap
• Two people record what the other does.
What is a Reflex action??
Reflex actions
• “An action that is performed
without conscious thought as a
response to a stimulus”
• The signals from the receptors
do not travel to the brain,
instead they travel through
what we call a Reflex Arc.
• Spinal reflexes or Brain Reflexes
• Stimulus – receptor – sensory
neuron – association neuron –
motor neuron – Effector Response
Try These??
• Draw one reflex arc for your body’s response to
touching a hot object.
• Draw one reflex arc for your body’s response to
standing on something sharp.
• Draw one reflex arc showing your body’s response
to a loud noise.
Stimulus Response Model.
• How does our body react to normal stimulus??
• In a reflex:
o Stimulus – Receptor – Messenger – Association neuron – Messenger –
Effector - Response
• In a normal response:
o Stimulus – Receptor – Messenger - Coordinating system - Messenger –
Effector - Response
Try These??
• Draw a stimulus response
model for how the body
would handle a change
in temperature?
• Draw a stimulus response
model for how the body
may respond to a drop in
water concentration?
• Draw a stimulus response
model for how the body
may respond to a drop in
sugar levels?
• Hypothalamus (links our
nervous and endocrine
systems):
o
o
o
o
o
Control Metabolic Activities
Water Balance
Sugar Metabolism
Body Temperature
Hormone Secretion
Nervous System Review
1. Name the Two parts of the nervous system, and
provide there acronyms?
2. Draw and Label the Key Structures of a Motor
Neuron?
3. What are the two components of the CNS?
4. What are the two types of matter that make up our
CNS?
5. How many Neurons does our brain contain?
6. Name three parts of the Brain?
7. How much space does the Cerebrum take in our
brain?
8. What does PNS stand for and what are the two
components?
9. What are two examples of Receptors?
10. What function does our Somatic Nervous System
play?
11. What are the two types of Photoreceptors found in
the eye?
12. Apart from sound, what other function does our
ear play in our body coordination?
13. What are 3 examples of stimuli our skin can detect?