The autonomic nervous system Flashcards
what is the autonomic nervous system ?
A collection of motor neurones (efferents) in the central and peripheral nervous system that innervate smooth muscle, cardiac muscle and glands to regulate their activity
what are the three 3 subdivisions of the autonomic nervous system ?
Enteric
– Sympathetic
– Parasympathetic
whats the enteric nervous system ?
Works autonomously to control the activity of the GIT
• Consists mainly of the myenteric plexus
• Receives autonomic innervation from the parasympathetic and sympathetic divisions
what do you think of when you read sympathetic
fight or flight
what do you think of when you read parasympathetic
rest and digest
difference between cranial and spinal nerves?
Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), in contrast to spinal nerves (which emerge from segments of the spinal cord)
where does the parasympathetic nervous system originate ?
in the brainstem and sacral spinal cord
what do the sacral preganglionic neurons not join with ?
the spinal nerve
what do cranial preganglionic neurons travel with ?
axons in the cranial nerves
give me four examples of cranial nerves
vagus (X): lungs, heart, stomach, small intestines, liver
occulomotor(III) pupil size, lens strength
facial (VII): salivary glands
glossopharyngeal (IX): smooth muscle and glands of throat, viscera of thorax and abdomen
regarding the parasymptateic nervous system: are preganglionic fibres long or short and are they branched ?
long and branched
where is the ganglia of the parasympathetic nervous system ?
located on or close to their target organs
what are the properties of the postganglionic neurons of the parasympthathetic nervous system ?
short projections to innervate their target organs
regarding the parasympathetic nervous system.. whats the type of receptor in the ganglion
nicotinic cholinergic receptor (ionotropic)
regarding the parasympathetic nervous system.. whats the type of receptor in the effector organ
muscarinic cholinergic receptor (M1-5)
where does the sympathetic nervous system arise from ?
from the thoracic and upper lumbar cord
properties of preganglionic neurones in the sympathetic nervous system
short un branching preganglionic neurons
where is the ganglia located in the sympathetic nervous system ?
close to the vertebral column
properties of postganglionic neurones in the sympathetic nervous system ?
long branching projections to innervate their target organs
where do sympathetic preganglionic neurones arise from ?
the lateral horn of the spinal grey matter and they axons leave through the ventral root, travel via the white rami to enter the sympathetic chain
what do sympathetic neurons do after entering the sympathetic chain
Synapse with postganglionic neurones in the sympathetic chain
– Travel along the sympathetic chain before leaving along a nerve to innervate an outlying ganglion or the adrenal gland
– Leave the sympathetic chain to innervate a collateral ganglion
what would sympathetic innervation of blood vessels result in ? whats the neurotransmitter involved
vasodilation.. epinephrine
what would sympathetic innervation of cardiac muscle result in ?
contraction.. epinephrine is the neurotransmitter