Anatomy of the ANS Flashcards
Where are the preganglionic neurons of the Sympathetic division located?
Thoracic and lumbar regions of the spinal cord
Two types of sympathetic ganglia
Sympathetic chain ganglia
Collateral ganglia
Where are the Sympathetic chain ganglia located
alongside the vertebral column, with origination in the thoracic and lumbar region but extension into cervical and sacral regions
Where are the Collateral ganglia located?
abdominopelvic cavity; anterior to the vertebral column
White ramus communicans
short connection between a spinal nerve and sympathetic chain ganglion where a preganglion axon passes
4 exit routes for sympathetic axons
1) Spinal nerves
2) Sympathetic nerves
3) Splanchnic nerves
4) Innervation to adrenal gland
Adrenal medulla
Where axons of sympathetic division exit and synapse for innervation to the adrenal gland.
It is the inner portion of the adrenal gland that gives rise to the postganglionic cells of the ANS.
cells are round, no axons or dendrites, and secrete either epinephrine or norepinephrine
Parasympathetic division
Craniosacral division - cell bodies of parasympathetic preganglionic neurons are either in cranial nerve nuclei in the brain stem or sacral region
Which cranial nerves are parasympathetic axons in?
III, VII, IX, X
Pelvic splanchnic nerves
Axons of the parasympathetic division associated with the sacral region
Terminal ganglia
Where preganglionic axons synapse with postganglionic neurons
Autonomic nerve plexuses
complex, interconnected neural networks formed by neurons of the sympathetic and parasympathetic divisions
4 distributions of the sympathetic nervous division
1) Spinal nerves
2) Head and neck nerve plexuses
3) Thoracic nerve plexuses
4) Abdominopelvic nerve plexuses
Two plexuses of the thoracic nerve plexus or the sympathetic nervous division
Cardiac plexus > heart
Pulmonary plexus > lungs
Celiac plexus
Innervates diaphragm, stomach, spleen, liver, gallbladder, adrenal glands, kidney, testes, and ovaries
Superior Mesenteric plexus
innervates pancreas, small intestine, ascending colon, and transverse colon
Inferior mesenteric plexus
innervates transverse colon to rectum
Superior and inferior hypogastric plexuses
innervate descending colon to the rectum, urinary bladder, and reproductive organs
4 distributions of the parasympathetic nervous division
1) Cranial nerves
2) Vagus nerve
3) Abdominal nerve plexus
4) Pelvic splanchnic nerves and pelvic nerve plexuses
Ocoulomotor nerve (III) innervation
ciliary muscles and iris of the eye
Facial nerve (VII) innervation
lacrimal gland and mucosal glands and salivary glands
Glossopharyngeal IX) nerve
innervates parotid salivary gland
Vagus nerve X
Somatic motor and sensor function of head and neck, but parasympathetic distribution to thorax and abdomen
Contributes to innervation of the cardiac plexus, pulmonary plexus, and forms esphageal plexus
Enteric nervous system plexuses come from which 3 sources?
1) Sensory neurons that connect the digestive tract to the CNS
2) ANS motor neurons connecting the CNS to digestive tract
3) Enteric nuerons
3 types of enteric neurons
Enteric sensory neurons
Enteric motor neurons
Enteric interneurons
What do Enteric sensory neurons do?
detect changes in chemicals of digestive tract or changes in stretch of tract wall
What do Enteric motor neurons do?
stimulate or inhibit smooth muslce contraction and gland excretion
What do Enteric interneurons do?
connect enteric sensory and motor neurons to each other.
