Autonomic Nervous System

Question 1

Functional Definition of ANS

Answer 1

controls involuntary visceral activity in order to maintain homeostasis or respond to stress

Question 2

Anatomical Definition of ANS

Answer 2

• General Visceral Efferent system
• General Visceral Afferents
• components of CNS that regulate visceral activity

Question 3

General Visceral Efferent (GVE) System

Answer 3

• Divided physiologically and anatomically into 2 components
• Sympathetic
• Parasympathetic

Question 4

Sympathetic

Answer 4

• fight or flight

- thoracolumbar

Question 5

Parasympathetic

Answer 5

• homeostasis -> “rest & digest”

- craniosacral

Question 6

The GVE system is a 2 neuron pathway. What does that involve?

Answer 6

• takes 2 neurons to get from CNS to effector
• Ganglion provides the synapse location (Not same ganglion for sym and parasym!)
• Thus has a preganglionic component and a postganglionic component

Question 7

The first part of the sympathetic nervous system is ALWAYS the same. What is it?

Answer 7

lateral gray horn -> ventral root -> spinal nerve -> ramus communicans -> sympathetic trunk

Question 8

Parasympathetic Nervous System

CN III, VII, IX

Answer 8

covered with head

Question 9

Parasympathetic Nervous System
CN X (vagus n.)

Answer 9

thoracic and abdominal viscera

Question 10

Parasympathetic Nervous System

Sacral Spinal Cord

Answer 10

pelvic viscera

Question 11

Sympathetic Pathway

Body Walls and Limbs

Answer 11

Preganglionic Pathway: lateral gray horn (of T1-L5 ) → ventral root → spinal nerve → ramus communicans → sympathetic trunk →
Ganglion: sympathetic trunk ganglia →
Postganglionic Pathway: rami communicantes to spinal nerves → dorsal or ventral branches of spinal nerves

Question 12

Sympathetic Pathway

Head

Answer 12

Preganglionic Pathway: lateral gray horn (of ~T1-T3) → ventral root → spinal nerve → ramus communicans → sympathetic trunk → ansa subclavia → cervical sympathetic trunk (vagosympathetic trunk) →
Ganglion:cranial cervical ganglion →
Postganglionic Pathway:internal and external carotid nerve plexuses (nerves follow blood supply to the head)

Question 13

Sympathetic Pathway

Neck

Answer 13

Preganglionic Pathway: lateral gray horn (of ~T3-T5) → ventral root → spinal nerve → ramus communicans → sympathetic trunk →
Ganglion:cervicothoracic ganglion →
Postganglionic Pathway:vertebral nerve → rami communicantes to cervical spinal nerves → dorsal or ventral branches of cervical spinal nerves

Question 14

Sympathetic Pathway

Thorax

Answer 14

Preganglionic Pathway: lateral gray horn (of ~T5-T8) → ventral root → spinal nerve → ramus communicans → sympathetic trunk → [ansa subclavia]
Ganglion:cervicothroracic ganglion [or middle cervical ganglion] →
Postganglionic Pathway:branches from ansa subclavia [or branches coursing with vagus nerve]

Question 15

Sympathetic Pathway

Abdominal Caivty

Answer 15

Preganglionic Pathway: lateral gray horn (of ~T7-L2) → ventral root → spinal nerve → ramus communicans → sympathetic trunk → major, minor, or lumbar splanchnic nerves
Ganglion: prevertebral ganglia within plexuses (celiacomesenteric ganglion, caudal mesenteric ganglion, others) →
Postganglionic Pathway: nerve plexuses on abdominal vessels (nerves follow blood supply to abdominal viscera)

Question 16

Sympathetic Pathway

Pelvic Cavity

Answer 16

Preganglionic Pathway: lateral gray horn (of lumbar cord segments) → ventral root → spinal nerve → ramus communicans → sympathetic trunk → lumbar splanchnic nerves →
Ganglion: caudal mesenteric ganglion →
Postganglionic Pathway: left/right hypogastric nerves → pelvic plexus → [branches which follow blood vessels to pelvic viscera]

Question 17

Parasympathetic Pathway
Vagus Nerve
Thorax

Answer 17

Preganglionic Pathway: parasympathetic nucleus of vagus nerve → vagus nerve → vagosympathetic trunk → vagus nerve → vagal branches to heart, lungs, etc (cardiac nerves) [recurrent laryngeal nerves]
Ganglion: terminal ganglia (within organs innervated) →
Postganglionic Pathway: within organ

Question 18

Parasympathetic Pathway
Vagus Nerve
Abdomen

Answer 18

Preganglionic Pathway: parasympathetic nucleus of vagus nerve → vagus nerve → vagosympathetic trunk → vagus nerve → dorsal & ventral vagal branches → dorsal & ventral vagal trunks → dorsal vagal trunk joins celiacomesenteric plexus via celiac branch, ventral vagal trunk goes directly to stomach and liver
Ganglion: terminal ganglia (within organs innervated) →
Postganglionic Pathway: within organ

Question 19

Parasympathetic Pathway

Sacral Spinal Cord

Answer 19

Preganglionic Pathway: intermediate gray matter (of S1-S3) → ventral root → spinal nerve → ventral branch → lumbosacral plexus → pelvic nerve → pelvic plexus
Ganglion: pelvic ganglia within pelvic plexus →
Postganglionic Pathway: branches from pelvic plexus to pelvic viscera