1. Aim: What is a reflex arc?
Do Now: How does the brain talk to the rest of the body?
It is connected to ____________ which is connected to the body by __________

2. STIMULUS, RESPONSE, IMPULSE
A change in the environment is ____________
Reaction to the change is _____________
A message through the nervous system is __________
A nerve cell is ____________

3. Yes, Mr. President, it is in the center…a part of your central nervous system…and so is your spinal cord!!!!

6. Nervous system is divided into 2 main parts: Central and Peripheral.

8. NEURON: Direction of impulse

10. Impulse traveling…it’s a relay race…

11. What happens if there is an emergency?
Like, your finger is on fire?
There is no time for the spinal cord to talk to the brain…
If you remember, its your spinal cord that connects your body parts to the brain through_______________
So spinal cord has to take action…
REFLEX ACTION

12. Reflex action
Being an involuntary action or response, such as a sneeze, blink, or hiccup.
Produced as an automatic response or reaction

13. Btw, who takes orders from the brain to move your effectors (I mean muscles and some glands?
MOTOR NEURONS!

14. Knee jerk response...

15. Reflex arc

16. The reflex action

17. Can you give other examples of reflexes…

18. Peripheral Nervous System (2 Types)
Somatic nervous system
is for voluntary muscle control. These neurons control the skeletal muscles….
Also some spinal reflexes. EX = patellar reflex
Autonomic nervous system
is automatic. Control of heart rate, respiration, blood pressure, smooth muscle, etc.
This has 2 separate divisions: sympathetic and parasympathetic
Copy yes

19. An Overview of the (copy) Nervous System:
Peripheral Nervous System
Central Nervous System
-Brain
-Spinal Cord
Sensory Neurons
-carry messages towards spinal cord from sensory receptors
Motor Neurons
-carry signals away from CNS
Somatic System: Voluntary Nerves
--neurons control skeletal muscles
Autonomic System:
Visceral, Involuntary
--heart, blood vessels, digestive organs, smooth muscle

20. Neurotransmitters… Acetylcholine: in skeletal muscles
Norepinephrine and Epinephrine: respond to stress
Dopamine & Serotonin: in the brain
Enzymes break down neurotransmitters so neurons are not “over stimulated.”
Ex. = cholinesterase (breaks down acetylcholine).

21. Neurotransmitters…

22. Neurotransmitters…
After they have conveyed the impulse to the next neuron, what happens to the neurotransmitters?