Autonomic Nervous System Physiology Flashcards
Compare and contrast the autonomic and somatic nervous systems.
The ANS is involuntary, slow, diffuse, disynaptic, and generally innervates smooth muscles, cardiac muscles, and glands, while the SNS is voluntary, fast, monosynaptic, specific, and innervates skeletal muscle.
What are the inputs to the ANS?
(1) the solitary tract in the medulla conveys visceral sensory information; (2) brainstem nuclei convey environmental stimuli; and (3) the hypothalamus conveys body states/goals
The ANS outputs to _________.
numerous organs
The parasympathetic cell bodies originate in the ___________.
brainstem and sacral spinal cord
There are post-__________ than post-__________.
sympathetic; parasympathetic
Both the pre-ganglionic sympathetic and pre-ganglionic parasympathetic use ______ as their neurotransmitters, while the post-ganglionic sympathetic uses _______ and post-ganglionic parasympathetic uses _________.
acetylcholine; norepinephrine; acetylcholine
The adrenal medulla is functionally a __________.
sympathetic ganglion, because it is innervated by pre-ganglionic sympathetic neurons and releases epinephrine and norepinephrine
How does sympathetic stimulation increase blood pressure?
It constricts blood vessels and increases heart rate
Parasympathetic stimulation lowers the blood pressure by __________.
decreasing heart rate and contractility
The somatic neuronal cell bodies reside in the _________.
CNS
The autonomic neuronal cell bodies reside in the __________.
sympathetic chain ganglia and the parasympathetic plexuses
Norepinephrine works by _________.
activating PKA which stimulates CaL and activating adenylate cyclase which catalyzes cAMP and then activates HCN (which speeds up repolarization)
Acetylcholinergic M2 muscarinic receptors work by ___________.
deactivating adenylate cyclase (which halts PKA) and then activating potassium channels
Atropine is a _________.
M2 antagonist, therefore it increases heart rate; this class of drugs is called “sympathomimetic”
There is one region of the brain that does not have the blood-brain barrier: ___________.
the subfornical region; this is used to detect hormones in the blood–in the case of blood pressure, angiotensin II; in response to angiotensin II, the subfornical region releases ADH to increase water retention