ANATOMY OF AUTONOMIC NERVOUS SYSTEM Flashcards
what is the somatic nervous system?
The part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles.
what’s the autonomic nervous system?
a control system that acts largely unconsciously and regulates bodily functions by supplying smooth muscle, cardiac muscle and glands.
what neurotransmitters are used in the somatic nervous system?
acetylcholine
what neurotransmitters are used in the autonomic nervous system?
acetylcholine and noradrenaline
what are the subgroups in the autonomic nervous system?
sympathetic
parasympathetic
enteric
what is the function of the enteric nervous system?
To control gastrointestinal behaviour independently of CNS input
what are the effects of the sympathetic nervous system?
increased heart rate and bp increased breathing rate diverts blood to skeletal muscles dilation of pupils inhibits peristalsis constricts intestinal and urinary sphincters
what are the effects of the parasympathetic nervous system?
decreases heart rate and bp
decreases breathing rte maintains even blood supply throughout the body
constriction of pupils
stimulates peristalsis
relaxes intestinal and urinary sphincters
where do parasympathetic nerves arise from?
brain stem (cranial nerves 3,7,9,10) and sacral plexus (S2,S3,S4) =craniosacral
where do sympathetic nerves arise from?
T1-L2 spinal segments
=thoracolumbar
describe the length of pre-ganglionic neurones in the parasympathetic nervous system?
long axons an synapse with ganglion cells close to effector so short post-ganglionic neurones
describe the length of pre-ganglionic neurones in the sympathetic nervous system?
short axons and synapse with ganglion cells close to spinal cord so long post-ganglionic neurons
what is the sympathetic chain?
A paired bundle of nerve fibers just lateral to the vertebral bodies.
what are paravertebral ganglia?
Interconnected autonomic ganglia that lie close to the spinal nerves and the vertebrae. The chains of paravertebral ganglia are paired, and lie just lateral to the bodies of the vertebrae.
what are prevertebral ganglia?
Midline structures located anterior to the aorta and vertebral column, and are represented by the celiac ganglia, aortic–renal ganglia, and the superior and inferior mesenteric ganglia.
what are the 3 options for sympathetic neurones to do when they enter into the sympathetic chain?
synapse and head out through the grey ramus communicans to become a spinal nerve
ascend or descend within the chai before synapsing
it could not synapse and just continues straight through to reach prevertebral ganglion- a splanchnic nerve
how do preganglionic neurones enter the sympathetic chain?
via the white ramus communicans
what is the function of white rami communicans?
Carry presynaptic sympathetic fibers from the ventral primary rami to the sympathetic trunk
where do white ramus communicans exist?
Only between T1-L2 spinal segements
what is the function of grey ramus communicans?
Carry postsynaptic sympathetic fibers from the sympathetic trunk to all spinal nerves.
what is a structural difference between pre- and post-ganglionic neurones?
pre are myelinates
post are unmyelinated
where does the great splanchnic nerve arise from?
T5-T9
where does the lesser splanchnic nerve arise from?
T9-T10
where does the least splanchnic nerve arise from?
T12
where does the lumbar splanchnic nerve arise from?
L1-L2
which nerve innervates constriction of the eye and increased salivation?
cranial nerves 3,7 and 9
which nerve causes decreased HR and BR and increased digestion?
vagus nerve
which area of the spinal cord is responsible for relaxing sphincters (in bladder and anus) and erections?
sacral plexus
