The Autonomic Nervous System

Splanchnic nerve

neurons pass through the sympathetic trunk ganglia toward effector

sympathetic nervous system

fight or flight

parasympathetic nervous system

rest and digest

dual innervation

organs receive instructions from both sympathetic and parasympathetic divisions

autonomic sensory neurons

the main input to the ANS; monitors internal conditions

autonomic motor neurons

out of the ANS; effectors are cardiac muscle and smooth muscle

preganglionic neuron

CNS to ganglion

postganglionic neuron

ganglion to effector

thoracolumbar divsion

sympathetic nervous system

SNS actions

dilates pupils, increases heart rate, decreases digestion

sympathetic trunk ganglia

lie next to the spinal column

superior cervical ganglion

head and heart

middle and inferior cervical ganglia

heart, blood vessels of the neck, shoulder, and upper limb

thoracic ganglia

innervate visceral organs and skin

White Ramus (White Rami Communicantes)

contains myelinated axons going to an autonomic ganglion

grey rami

unmyelinated; axons exit toward effectors

prevertebral ganglia

lie anterior to the vertebral column and close to the large abdominal arteries

celiac ganglion

stomach, spleen, pancreas

sup. mesenteric ganglion

portions of the large intestine and all of the small intestine

inf. mesenteric ganglion

terminal end of large intestine

aorticorenal ganglion

kidney

renal ganglion

kidney

celiac plexus

nerve network that surrounds the aorta; formed by the aorticorenal, celiac, and sup. mesenteric ganglia

greater, lesser, least splanchnic n.

associated with the celiac plexus

adrenal medulla

preganglionic neurons of the SNS extend into this region

SNS preganglionic neurons

short

SNS postganglionic neurons

long

craniosacral division

parasympathetic division

terminal ganglia

located close to effector

ciliary ganglion

Site of postganglionic nerve cells that elicits constriction of pupil; CN 3

Miosis

constriction of the pupil

Pterygopalatine ganglion

postganglionic fibers synapse on nasal mucosa and lacrimal glands; CN 7

Otic ganglion

parotid salivary gland; CN9

Submandibular ganglion

submandibular and sublingual salivary glands; CN 7

Vagus nerve

80% of craniosacral outflow; lowers HR, regulates peristalsis, speech

pelvic splanchnic nerves

innervates the inf. hypogastric plexus

inferior hypogastric plexus

innervates reproductive structures and bladder

PSNS Preganglionic Neurons

long

PSNS Postganglionic Neurons

short

PSNS effects

constriction of pupils, activates GI tract, decreases heart rate

Drug that activates the SNS

methamphetamine

Drugs that activate the PSNS

fentanyl and heroin