1. Nervous System
Physiology

2. Nervous System
Function: Coordinates & controls body’s response to internal/external environment
Structures: Brain, spinal cord, nerves, sense organs, receptors

3. 2 Major Divisions
1. Central Nervous System (CNS) 2. Peripheral Nervous System (PNS)

4. Central Nervous System
The Brain
Function: Oversees daily operation of body & interprets info it receives
Structures: Cerebrum, Cerebellum, Brain stem

5. Brain
Cerebrum: Largest, voluntary activities senses, intelligence, learning, & judgment.
Cerebellum – 2nd largest part of the brain. Controls muscle coordination & balance
Brain stem- links the cerebrum w/ spinal cord. Controls breathing, swallowing, blood pressure, & heart rate.

6. Spinal Cord

7. Spinal Cord
Links brain to body. Brain  Spinal cord  Body Reflexes are processed in spinal cord.

8. Peripheral Nervous System (PNS)
nerves outside the brain and spinal cord.
send and receive messages with the CNS.

9. Peripheral Nervous System
Somatic Nervous System
Autonomic Nervous System

10. Somatic Nervous System - Voluntary
Relays information from senses CNS  muscles
Ex. Reach for a book

11. Autonomic Nervous System - Involuntary
Relays info from CNS  internal organs
Ex. Heart rate, breathing

12. Reflex Arc
- rapid, involuntary muscle movement
Involves only neurons & spinal cord
Brain gets bypassed!!

13. Reflex Arc

14. Structure of a Neuron

15. Action Potential

16. Types of Neurons
A. SENSORY neuron – from body to CNS (sense stimuli)
B. INTERNEURONS –from CNS to motor neurons(connect)
C. MOTOR neuron – from CNS to muscle/gland (move)

17. Neuron Organization
Neurons don’t touch!
IMPULSE = electrochemical messages
SYNAPSE = space between 2 neurons

18. Synapse

19. Receptors and Sense Organs
Sensory receptors are neurons that are specialized to detect a stimulus.
They are found in HIGH concentration in the sense organs (eyes, ears, nose, mouth & skin).
They are found in LOW concentration throughout the rest of the body.

20. Types of Sensory Receptors
Mechanoreceptors – respond to movement, pressure & tension. Photoreceptors – respond to variations in light. Chemoreceptors – respond to chemicals. Thermoreceptors – respond to changes in temperature. Nociceptors – respond to tissue damage & pain.

21. Nervous System and Drugs
Stimulants
Cocaine, nicotine, caffeine, amphetamines
Increase the speed of messages being sent
Feeling of energy and wellness
After effect wears off  fatigue & depression

22. Nervous System and Drugs
2. Depressants
Alcohol, Barbiturates, muscle relaxers, sleeping pills
Slows down messages
-Feeling of being relaxed, calm, sleepy
Can slow down the system too much  body stops breathing