3. Human Nervous System
The human nervous system is made up of two different systems the Central Nervous System and the Peripheral Nervous System.

4. Central Nervous System
The Central Nervous System (CNS) is composed of:
a hollow, dorsal nerve cord (spinal cord)
the brain
The CNS is the part of the nervous system that
coordinates all neural functions.
It consists of the spinal cord and the brain.
It contains the “reflex arc” which is the
pathway that the nerve impulse follows as
a normal reflex.

5. The Spinal Cord:
It is about as thick as a finger (little less than 1 cm in diameter).
It is made up of the same grey matter the brain is, but it also has a white matter exterior.
It is soft, light and flexible.

6. It has a two-way communication system:
The inner gray matter controls the side-to-side movement of the impulse across the spinal cord.
The outer white matter moves the impulse up and down the spinal cord to-and-from the brain.

7. Spinal Cord Injuries

8. The Reflex Response
The spinal cord is the organ of the nervous system that is involved with the reflexes of the body. For example, pulling away a hand from a hot stove is a reflex response.

9. The Stages of a Reflex Response:
The reflex arc pathway begins with a sensory organ detecting a dangerous stimuli.

10. 2) The impulse then passes from the sensory organ to the sensory neuron.

11. 3) The sensory neuron then takes the impulse quickly to the spinal cord.

12. 4) The spinal cord then passes the information to a motor neuron that
transfers the impulse to the structure that can respond to the dangerous
stimulus.

14. Reflex Response Tests
The Colour Box Reflex Test:
The Image Test:
Hit the “X” Test:
Hit the “Dot” Test:
Sleepy Sheep!:

15. Peripheral Nervous System
The Peripheral Nervous System (PNS) is composed of:
i) All of the neural structures outside of the brain and spinal cord and these
are organized into the somatic system and autonomic system.

16. The Somatic System (Voluntary):
Made up of all of the sensory and motor neurons in the body outside of the central nervous system.
For example, all of your skeletal muscles are part of this system. Therefore the ability wiggle your toes, to sense pain, and to consciously control the workings of your body are a result of the functions of the somatic system.

17. The Autonomic System (Involuntary):
Controls the actions of the muscles over which we have no control.
For example, movements of the stomach and the intestines, heart rate, goose bumps, pupil constriction, and thoughtless breathing are all due to the autonomic system.

18. The Autonomic System has 2 Important Divisions:
The Sympathetic Nervous System
The Parasympathetic Nervous System
These two systems act in an antagonistic fashion.

19. Parasympathetic Effect
Organ
Sympathetic Effect
“pumped up”
Parasympathetic Effect
“calming down”
Pupil of the Eye
dilates
constricts
Heart
accelerates
slows
Intestines
decrease movement
increase movement
Salivary Glands
decrease secretion
increase secretion
Lungs
dilate air passages
constricts air passages
Metabolism
increases
decreases
Fight vs Flight.

20. Nervous System Flow Chart

21. Fantastic Video!
The Human Nervous System Part 1:
Human nervous system part 2.