1. AUTONOMIC NERVOUS SYSTEM NOTES
CHAPTER 14
AUTONOMIC NERVOUS SYSTEM NOTES

2. 2 Our internal environment constantly deviates from the optimum norm so our systems need to be constantly functioning to bring these changes back to the optimum levels and maintain homeostatic balance
Many systems contribute to this stability though it is primarily dependant on the Autonomic Nervous System
It’s a system of motor neurons (no sensory) that innervates smooth and cardiac muscle and glands.

3. 3
It performs all of these tasks involuntarily without any conscious thought
Involuntary means smooth muscle
Go back to the hypothalamus, pg
Medulla oblongata, pg 449

4. 4 The ANS is divided into two divisions:
Sympathetic & parasympathetic
Sympathetic- “Fight or flight” activates when we are excited or in emergency or threatening situations
Parasympathetic- “Resting or digesting” activities

5. 5 Figure: 14.1; page 526

6. 6 SKIP

7. 7 SKIP

8. 8 SKIP

9. 9 SKIP

10. 10 General Anatomy
In the somatic system (voluntary effectors) there is only one motor unit (dendrites, body,axon)
This is true for the sensory units as well except there is no sensory part of the ANS

11. 11 Each motor unit in the ANS consists of 2 motor neurons: 1
11 Each motor unit in the ANS consists of 2 motor neurons: A Preganglionic neuron with its cell body in the CNS, its preganglionic axon synapses in an autonomic ganglion
2. A Postganglionic neuron with its cell body in an autonomic ganglion with a postganglionic axon extending to the effector

12. 12 Figure: 14.2; page: 527

13. 13 The arrangement of the 2 motor units and subsequently the 2 ganglions are somewhat different between the parasympathetic and the sympathetic divisions
Pararsympathetic (Craniosacral) Division Rest and digest
-Preganglionic fibers (axons) come from the cranial nerves and the sacrum
-The preganglionic axons go to the terminal ganglion that is located just outside the effector or inside the effector

14. 14 Figure: 14.4; page: 529

15. 15 Figure: 14.4; page: 529

16. 16 Figure: 14.4; page: 529

17. 17 Sypmpathetic (thoracolumbar) division - fight or flight More complex
All preganglionic fibers (axons) arise from preganglionic neurons in spinal cord segments T1-L2
The preganglion neurons are in the lateral horns of the spinal cord gray matter
The preganglionic axons all go to a sympathetic trunk ganglion which are all interconnected and aligned up in orderly fashion along the side of the spine

18. 18 Fig. 12.31; pg. 469 ventral, dorsal, lateral

19. 19Figure: 14.6; page: 533 sympathetic

20. 20 Figure: 14.6; page: 533

21. 21 Figure: 14.6; page: 533 collateral ganglion

22. 22 More complicated – The preganglionic axons can do one of three things when they reach the chain
They can synapse w/ the chain ganglia at that level
The axon can ascended or descend to another trunk ganglion – This is what holds the chain together
They can pass through the trunk completely and synapse with a distant collateral ganglion

23. 23 Figure: 14.5; page: 531 same level

24. 24 Figure: 14.5;page:531 ascending/descending

25. 25 Figure: 14.5; page: 531 collateral ganglion