Lecture 14 9/11/23 Flashcards
Which part of the brain controls the autonomic nervous system?
hypothalamus
How does the ANS differ from the somatic nervous system?
there is no voluntary control over the actions of the ANS
What are the two branches of the ANS?
-parasympathetic nervous system
-sympathetic nervous system
How do the sympathetic and parasympathetic nervous systems differ in terms of activity?
-PNS is continuously active
-SNS has low resting tone but is capable of bouts of great activity
How many neuronal cell bodies does each ANS neuron system have?
two
Where are the two neuronal cell bodies located for each ANS neuron system?
-1st in the CNS
-2nd in the ganglion of PNS
What is the term for the first neuron of an ANS neuron system?
preganglionic neuron
What is the term for the second neuron of an ANS neuron system?
postganglionic neuron
Where do the parasympathetic ANS fibers leave the CNS?
brainstem and sacral spinal cord
Where do the sympathetic ANS fibers leave the CNS?
thoracolumbar spinal cord (T1-L3)
What do the preganglionic fibers do after leaving the CNS?
reach the ganglions and synapse with the postganglionic neurons
What is the overarching role of the sympathetic nervous system?
fight or flight
What is the anatomy of the 1st neuron in the sympathetic nervous system?
-short preganglionic axons
-run to the sympathetic trunk ganglia
What is the sympathetic trunk?
connected chain of paravertebral ganglia
What is the anatomy of the 2nd neuron in the sympathetic nervous system?
-long axons
-leave ganglion and go to target organ
What are the targets of the sympathetic nervous system?
-dilate pupil
-constriction of skin/gut blood vessels
-bronchodilation
-increased heart rate/contraction force
-piloerection
-decreased gut activity
-stimulation of sweat gland secretion
-stimulation of norepinephrine and epinephrine release
-close internal urethral sphincter
What is the overarching role of the parasympathetic nervous system?
rest and digest
What is the anatomy of the first neuron of the parasympathetic nervous system?
-originate from brainstem or sacrum
-long preganglionic axons
What is the anatomy of the second neuron of the parasympathetic nervous system?
-ganglia are close to or within wall of target organs
-small postganglionic axons
Which cranial nerves allow the parasympathetic preganglionic axons to exit and reach the organs of the head?
-3
-7
-9
-10
Which cranial nerve allows the parasympathetic preganglionic axons to exit and reach the rest of the body?
10
Which cranial nerve is associated with the muscles controlling pupil size?
CN 3
Which cranial nerves are associated with the salivary glands?
CN 7 and CN 9
Which cranial nerve is associated with the lacrimal glands?
CN 7
Which organs are CN 10 associated with?
organs in the thoracic and abdominal regions
Which spinal nerves allow the parasympathetic preganglionic axons to exit?
-S1
-S2
-S3
What are the targets of the parasympathetic nervous system?
-constrict pupil
-focus lens
-bronchoconstriction
-decrease heart rate
-increase gut activity
-release saliva
-contract bladder
-stimulate erection
What neurotransmitter acts in the preganglionic neurons of both the sympathetic and parasympathetic nervous systems?
acetylcholine
What receptor acts in the preganglionic neurons of both the sympathetic and parasympathetic nervous systems?
nicotinic acetylcholine receptors
What neurotransmitters act in the postganglionic neurons of the sympathetic nervous system?
-norepinephrine
-epinephrine
What receptors act in the postganglionic neurons of the sympathetic nervous system?
-alpha receptors
-beta receptors
What neurotransmitter acts in the postganglionic neurons of the parasympathetic nervous system?
acetylcholine
What receptor acts in the postganglionic neurons of the parasympathetic nervous system?
muscarinic acetylcholine receptors
What are the characteristics of the adrenal medulla?
-innervated by sympathetic fibers
-postganglionic chromaffin cells act as 2nd neurons and secrete epinephrine
-epinephrine is released into blood circulation
-helps stimulate stress response
Where are ALL preganglionic cell bodies located?
-CN 3, 7, 9, 10 (PNS)
-S1-S3 (PNS)
-T1-L3 (SNS)
What is the parasympathetic CNS origin?
craniosacral
What is the sympathetic CNS origin?
thoracolumbar
