Lecture 18

Question 1

What are the 2 divisions of the autonomic nervous system?

Answer 1

Sympathetic (T1-L2) and Parasympathetic (CN’s 3, 7, 9, 10 and S2-4)

Question 2

Preganglionic Neurons

Answer 2

Always myelinated; synapses with postganglionic neuron; utilizes acetylcholine

Question 3

Postganglionic Neurons

Answer 3

Originates from ganglion; never myelinated; generally utilizes norepinephrine

Question 4

Parasympathetic Nerves

Answer 4

Synapse on microscopic ganglion cells embedded in walls of target organs; primarily responsible for maintaining and coordinating gut function (secretion of fluids and peristaltic contractions)

Question 5

Sympathetic Nerves

Answer 5

Synapse on cells located in large, visible ganglia located in dorsal wall of coelom, typically anterior to abdominal aorta; involved in responses related to anger, fear, and anxiety; inhibits digestive fluid secretion, inhibits peristalsis, closes involuntary sphincters, constricts blood flow to gut

Question 6

Cervical Ganglia

Answer 6

Superior, middle, inferior; lies against neck of ribs and costovertebral junctions

Question 7

Thoracic Ganglia Pairs

Answer 7

12 pairs of ganglia; first one fused with inferior cervical ganglion; referred to as stellate ganglion collectively

Question 8

Cardiopulmonary Splanchnic Nerves

Answer 8

Travel on their own and do not accompany other nerves or vessels; function in coronary artery dilation, increase heart rate, bronchodilation

Question 9

Sympathetic Supply to Abdominal Organs

Answer 9

Preganglionic fibers do not synapse in paravertebral ganglia but pass medially to synapse on ganglion cells located around the aorta; postganglionic fibers travel from the preaortic ganglia to their target organs by following the arterial branches

Question 10

Thoracic Sympathetic Chain

Answer 10

Preganglionic sympathetic supply to the thoracic viscera are from T1-5; postganglionics are from superior, middle, and inferior cervical ganglia and T1-5 paravertebral ganglia

Question 11

Splanchnic Nerves

Answer 11

Composed of preganglionic fibers and visceral sensory fibers; supply abdominal viscera and synapse in prevertebral ganglia

Question 12

Greater Splanchnic Nerve

Answer 12

T5-9; synapses in celiac ganglion; also consists of celiac plexus and hepatic plexus

Question 13

Lesser Splanchnic Nerve

Answer 13

T10-11; synapses in the superior mesenteric ganglion

Question 14

Least Splanchnic Nerve

Answer 14

T12; synapses in the aorticorenal ganglion

Question 15

Celiac Ganglia

Answer 15

Prevertebral; superior to celiac trunk

Question 16

Celiac Plexus (cerebrum abdominale, solar plexus)

Answer 16

Sympathetic to: stomach, duodenum, ileum, jejunum, spleen, pancreas, gall bladder, kidneys, suprarenal glands; also carries pregnaglionic fibers of vagus nerve (parasympathetic fibers)

Question 17

Hepatic Plexus

Answer 17

Sympathetic to liver

Question 18

Superior Mesenteric Ganglia

Answer 18

Prevertebral; superior to plexus; sympathetic to: duodenum, ileum, jejunum, cecum, vermiform appendix, ascending colon, transverse colon, pancreas

Question 19

Aoritcorenal Ganglia

Answer 19

Prevertebral; sympathetic to: kidneys, suprarenal glands

Question 20

Abdomincal Sympathetic Trunk

Answer 20

Paravertebral; continuous with thoracic sympathetic trunk; lumbar splanchnic nerves (T11-L2); inferior mesenteric ganglion (prevertebral); superior and inferior hypogastric plexuses, which has sympathetic innervation to: descending colon and sigmoid colon, as well as rectus and pelvic structures

Question 21

Vagus Nerve

Answer 21

Cranial nerve X; major parasympathetic supply to thoracic and abdominal viscera

Question 22

Course of the Vagus Nerve

Answer 22

Parallel to esophagus (innervates esophagus); left vagus nerve becomes anterior vagal trunk, right vagus nerve becomes posterior vagal trunk; passes posterior to root of lung on each side, pierces diaphragm with esophagus, becomes gastric nerve; supplies viscera in thoracic cavity and supplies viscera in the abdominal cavity to the left colic flexure

Question 23

Left Recurrent Laryngeal Nerve from Left Vagus

Answer 23

Hooks around arc of aorta to left ligamentum arteriosum

Question 24

Right Recurrent Laryngeal Nerve from Right Vagus

Answer 24

Hooks around subclavian artery and therefore arises in the neck and not the thorax