Chapter 15: ANS Flashcards
3 divisions of the ANS
Sympathetic
Parasympathetic
Enteric plexus
Preganglionic neuron
The first neuron in any autonomic motor pathway.
Cell body in CNS.
Axon part of cranial or spinal nerve that synapses with postganglionic neuron
Thoracolumbar division
Sympathetic division.
Preganglionic neurons have cell bodies in lateral gray horns in 12 thoracic segments and first 2 lumbar segments.
Craniosacral division.
Parasympathetic. Cell bodies of preganglionic neurons located in nuclei of CN 3,7,9,10, and in lateral gray matter of S2-S4.
2 major types of sympathetic ganglia
Sympathetic trunk ganglia
Prevertebral ganglia
Preganglionic Sympathetic trunk ganglia
(Superior cervical
Middle cervical
Inferior cervical
Innervates organs above the diaphragm
Preganglionic Prevertebral ganglia
Celiac ganglion
Superior mesenteric
Inferior mesenteric
Aorticorenal
Renal
Innervates organs below the diaphragm
Preganglionic Parasympathetic ganglia
Ciliary
Pterygopalatine
Submandibular
Otic
Autonomic plexuses
Networks of SNS and PSNS axons in thorax, abdomen, pelvis.
Cardiac plexus
Pulmonary plexus
Celiac plexus
Superior mesenteric
Inferior mesenteric
Hypogastric
Renal
White ramus
Short pathway sympathetic preganglionic fibres pass through before entering the nearest sympathetic trunk.
Collectively called white communicating rami.
Numbers of sympathetic trunk ganglia
3 cervical
11 or 12 thoracic
4 or 5 lumbar
4 or 5 sacral
1 coccygeal.
Gray communicating rami
Structures containing SNS postganglionic axons that connect ganglia of sympathetic trunk to spinal nerves.
Cephalic periarterial nerves
SNS. Provides sympathetic innervation to the visceral effectors to face and head.
Sympathetic nerves
To the heart (T1-T4) via cardiac plexus
To the lungs (T2-T4) via pulmonary plexus
Splanchnic nerves
SNS.
Consists of nerves to abdominopelvic organs:
Greater splanchnic thoracic, lesser thoracic splanchnic, least thoracic splanchnic, lumbar splanchnic.
And to adrenal medulla: extends directly to chromaffin cells.
