ANS

Question 1

What is the difference between a nuclei and a ganglia?

Answer 1

Nuclei = collection of cell bodies in the CNS

Ganglia = collection of cell bodies in the PNS

Question 2

Which are the divisions of the autonomic nervous system, and from where do they originate?

Answer 2

Sympathetic:

• thoracolumbar
• lateral horns T1-L2

Parasympathetic

• craniosacral
• CN III, CN VII, CIX, CX
• S2-4

Question 3

Which neurotransmitters are used in the ANS?

Answer 3

PNS (all) and pre-ganglionic neuron of SNS:
- acetylcholine

post-ganglionic neuron of SNS:
- norepinephrine

Question 4

What types of receptors are activated by the ANS, and where are they located?

Answer 4

SNS:
Adrenergic receptors (excited by norepinephrine)

A1 - smooth mm in vessels
B1 - heart
B2 - lungs

PNS:
Cholinergic (muscarinic) receptors (excited or inhibited by acetylcholine)

M2 - heart
M3 - lungs

Question 5

Which divisions of the ANS are catabolic and which anabolic?

Answer 5

SNS = catabolic (energy expending)

PNS = anabolic (energy conserving)

Question 6

Which cranial nerves contribute motor innervation to the PNS, and through which cranial nuclei and PNS synapse?

Answer 6

CN III (Oculomotor)

• Edinga Westphall Nucleus
• Ciliary synapse

CNVII (Facial)

• Superior Salvitory Nucleus
• Pterygo-palatine and Sub-mandibular synapse

CN IX (Glossopharyngeal)

• Inferior Salvitory Nucleus
• Otic synapse

CN X (Vagus)

• Dorsal Motor Nucleus of X
• terminal nuclei (near effector organ / gland)

Question 7

Which cranial nuclei receives PNS visceral afferent input?

Answer 7

Solitary Nucleus (CN IX and CN X)

Question 8

Which neurons in the ANS are myelinated?

Answer 8

Pre-ganglionic: lightly myelinated

Post-ganglionic: not myelinated

Question 9

Describe the lengths of neurons in the SNS and PNS

Answer 9

SNS:
Pre-ganglionic (short)
Post-ganglionic (long)
- synapse in sympathetic chain

PNS:
Pre-ganglionic (long)
Post-ganglionic (short)
- synapse at or near effector

Question 10

Where do different PNS nerves synapse?

Answer 10

1. Paravertebral ganglion at same level (T1-6 cardiopulmonary splanchnic)
2. Paravertebral ganglion up or down the chain (head, limbs)
3. Prevertebral ganglion (T5-L2 abdomino-pelvic splanchnic)

Question 11

What are the PNS actions of the cranial nerves?

Answer 11

CN III (Oculomotor)

• pupil constriction
• lens accomodation

CN VII (Facial)
- lacrimal, nasal and salivary glands (tears, nasal congestion, saliva)

CN IX (Glossopharyngeal)
- parotid gland (saliva)

CN X (Vagus)

• pharynx
• cardiopulmonary
• GIT (stomach, intestines)
• liver, spleen

Question 12

What are the 3 ways that SNS neurons synapse in the sympathetic chain?

Answer 12

1. Synapse at the same level paravertebral ganglion (T1-6 cardiopulmonary splanchnic)
2. Ascend or descend in sympathetic chain and synapse at a different level paravertebral ganglion (head, neck, limbs)
3. Continues straight through paravertebral ganglion without synapsing, and synapse at prevertebral ganglion (T5-L2 abdominopelvic splanchnic)

Question 13

Describe the sympathetic chain

Answer 13

White rami:
- carries pre-ganglionic neurons from spinal cord

Paravertebral ganglion:
- site of synapse between pre- and post- ganglionic neurons

Grey rami:
- carry post-ganglionic neurons from paravertebral ganglion to effector

Prevertebral ganglion:

• site of synapse between pre- and post-ganglionic neurons for abdominopelvic splanchnic nerves
• located in front of vertebral column near aorta

Sympathetic chain:

• white rami present in T1-L2
• paravertebral ganglion and gray rami present at all levels