CHAPTER 12-16.1 FINAL EXAM

This is chapter 14.

1. Somatic vs. autonomic motor neurons?

Somatic = one neuron goes to skeletal muscle, voluntary control.
Autonomic = two neurons go to smooth/cardiac muscle & glands, involuntary control.

2. Preganglionic vs. postganglionic neurons?

Preganglionic neurons start in the CNS and go to ganglia.
Postganglionic neurons start in ganglia and go to the target organ.

3. 2 divisions of ANS?

Sympathetic (fight or flight) and parasympathetic (rest and digest).

4. How are the parasympathetic/sympathetic systems alike and different?

Both keep the body balanced.
Sympathetic speeds things up during stress.
Parasympathetic slows things down during rest.

5. What happens with autonomic neuropathy?

Organs like the heart, stomach, or bladder may stop working right.
It’s different from somatic neuropathy, which affects movement.

6. If a drug blocks sympathetic activity, what happens in emergency?

In an emergency, the body can’t raise heart rate or blood pressure properly — slower reaction.

7. How does the sympathetic NS help homeostasis?

Speeds up heart, opens airways, boosts energy in stress.

8. Sympathetic NS anatomy?

Preganglionic neurons start in thoracic/lumbar spinal cord.
Short preganglionic axons, long postganglionic axons

9. What neurotransmitters are used in the sympathetic system?

Preganglionic neurons release ACh.
Postganglionic neurons usually release norepinephrine (sometimes ACh or epinephrine).

10. What are the sympathetic effects on target organs?

Raises heart rate, opens airways, dilates pupils, slows digestion, tightens sphincters.

11. Where are sympathetic preganglionic neurons found?

In the spinal cord (lateral horns). Their axons go to ganglia.

12. Where are sympathetic postganglionic neurons found?

In sympathetic ganglia near the spine. Their axons go to organs.

13. What do sympathetic neurons release?

Preganglionic = ACh.
Postganglionic = mostly NE, sometimes ACh or epi

If there were a drug that selectively blocked nicotine receptors on sympathetic postganglionic neurons, the effects observed in a patient would be similar to those of the drug administered in flashcard 17. Explain why.

Blocking nicotinic receptors stops ACh from activating postganglionic neurons.
This shuts down the sympathetic response — just like alpha-2 drugs, which also reduce sympathetic output.

15. Parasympathetic role in homeostasis?

Lowers heart rate, increases digestion, helps relax the body.

16. Parasympathetic anatomy?

Preganglionic neurons are in the brainstem (cranial nerves) and sacral spinal cord.
They send long axons to ganglia near the target organ.
Postganglionic neurons are short and finish the path to the organ.

17. What happens if a drug activates alpha-2 receptors?

It shuts down sympathetic output = lower blood pressure.
Used for hypertension treatment

18. What if nicotinic receptors are blocked on postganglionic neurons?

No signal goes to target organ — same result as slowing down sympathetic activity.

19. If sympathetic ganglia to the heart are destroyed, why does HR still rise during exercise?

Because the adrenal medulla still releases epinephrine into the blood.

20. Main function of parasympathetic nervous system?

Rest, digest, store energy, and maintain calm body functions.

21. Where are parasympathetic neuron cell bodies?

Preganglionic: brainstem & sacral spinal cord.
Postganglionic: near or inside target organs

22. How do neuron arrangements differ between divisions?

Sympathetic:

• Preganglionic neurons are short

• Synapse in ganglia near the spine

• Postganglionic neurons are long and go to the organ

Parasympathetic:

• Preganglionic neurons are long

• Synapse in ganglia near or inside the organ

• Postganglionic neurons are short

23. How does parasympathetic NS affect blood pressure?

It slows heart rate, lowering blood pressure.

24. Parasympathetic effects on smooth muscle:

a. Pupil: constricts
b. Lens: rounds for close vision
c. Penis: increases blood flow (erection)
d. Digestive tract: increases movement
e. Sphincters: relax to let waste pass

25. What is autonomic tone?

It’s the normal background level of ANS activity — a balance between the parasympathetic and sympathetic system

26. How does the CNS control the ANS?

Hypothalamus and brainstem send signals to ANS neurons to keep body functions balanced.

27. Why do brainstem injuries affect autonomic function?

Because the brainstem houses control centers for heart rate, breathing, and digestion.

28. What if parasympathetic tone dominated the airways?

Bronchioles would stay constricted — harder to breathe