1. The Nervous System Introduction
Master control and communicating system

2. Learning Objectives
To determine the general functions and division/organization of the nervous system.

3. I. What is the nervous system?
The master controlling and communicating system of the body.

4. II. Functions of the Nervous System
1. Sensory Input- gathering information (senses).
To monitor changes occurring inside and outside the body.
Changes=stimuli
2. Integration= Brain
To process and interpret sensory input and decide if action is needed.

5. 3. Motor Output
A response to integrated stimuli
The response activates muscles or glands= effector organs.

6. Examples:
Smell a cookie  Sensory Input  Brain (process)  Motor Output  Hand to grab and eat cookie

7. Sensory Input, Integration or Motor Output?
You see a sabertooth tiger running at you. Your eyes send a nerve impulse to your brain.
Your brain processes that you are about to get attacked and eaten
A nerve impulse is sent from you brain to the muscles in your legs allowing you to run away from the sabertooth tiger
Sensory Input
Integration
Motor Output

9. III. How is the Nervous System Organized?
A. Central Nervous System (CNS)
Brain and Spinal Cord
Integrative and control centers
B. Peripheral Nervous System (PNS)
Nerves (spinal nerves, cranial nerves)
Communication lines between CNS and rest of body.
Two Divisions of PNS:
1. Sensory (afferent) Division: Sensory receptors  CNS
2. Motor (efferent) Division: CNS  effectors (muscles and glands)

10. Motor Division
a. Somatic Nervous System (voluntary)- control skeletal muscles
b. Autonomic Nervous System (ANS) (involuntary)- regulates smooth muscles, cardiac, glands

11. Divisions of ANS:
1. Parasympathetic NS- “resting and digesting system”
Most active in non-stressful situations
Keeps energy use low and maintains vital housekeeping activities running.
2. Sympathetic NS- “fight or flight” division
Exercise, excitement, emergency, and embarrassment division.
Prepares the body for action.

13. 1. Central Nervous System
2. Peripheral Nervous System
A. Sensory Division
B. Motor Division
1. Somatic NS
2. Autonomic NS
A. Parasympathetic NS
B. Sympathetic NS

15. Example 1: CNS: brain & spinal cord (processes and interprets)
Step on nail
Muscles of leg (effector)= somatic
Sense organ (pain receptor in foot)
PNS: nerves (motor)
Move foot away from nail
PNS: nerves (sensory)

16. Example 1: Sense organ (pain receptor in foot) Step on nail
Sensory input
PNS: nerves (sensory)
CNS: brain & spinal cord (processes and interprets)
Motor output
PNS: nerves (motor)
Muscles of leg (effector)= somatic
Move foot away from nail

17. Example 2: CNS: brain & spinal cord (processes and interprets)
Low oxygen
Sense organ/receptor
PNS: nerves (motor)
PNS: nerves (sensory)
Lungs and Diaphragm to breathe= autonomic (parasympathetic ns)

18. Example 2: Sense organ/receptor Low oxygen PNS: nerves (sensory)
Sensory input
PNS: nerves (sensory)
CNS: brain & spinal cord (processes and interprets)
Motor output
PNS: nerves (motor)
Lungs and Diaphragm to breathe= autonomic (parasympathetic ns)