Histo Lecture 14
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Histo Lecture 14
Autonomic Nervous System
Where do the sympathetic fibers originate?
Thoracolumbar spinal cord (T1-L3)
Where do the parasympathetic fibers originate?
Brain stem and sacral spinal cord
Where do the fibers of the enteric system originate?
Within nerve plexi of GI tract
What do preganglionic neurons use as neurotransmitters?
What do postganglionic neurons use as neurotransmitters?
Ach or NE
What is the functional control of the ANS?
GI motility and secretion
urinary bladder emptying
respiratory tract secretion
How do we adapt to the following environmental stimuli: light, temperature, stress
light - pupillary constriction and dilation
temperature - vasodilation and sweating; vasoconstriction
stress - "fight or flight" response
ANS action are reflexive, based on what?
GVA input to the CNS
ANS can be altered by what state?
Divergence permits what?
Signals to be sent with diffuse distribution to a target
Receptors of the ANS are scattered widely over what?
Cell membrane without a defined "synapse"
Receptors of effector cells can be ______ or _____
inhibited or stimulated
What 3 structures provide AND efferents?
Action at effector organs are dependant on what?
NT receptors present in the tissue (Ach, NE/EPI)
What is the main coordinator of all ANS output?
Midbrain, pons, and medulla contain nuclei that:
Participate in visceral-motor outflow
Are areas of synapse for GVA sensory input
Project from GVA ganglia to GVE ganglia
Spinal cord can provide what without any higher level input?
some reflex efferent outflow
What do mechano & chemoreceptors provide?
Sensory receptors that provide GVA information
DRG project to what?
Hypothalamus and reticular formation
What projects to the solitary nucleus and/or vagus sensory nucleus?
Geniculate ganglion (CN VII)
Petrosal ganglion (CN IX)
Nodose ganglion (CN X)
Cholinergic neurons use what?
Adrenergic neurons use what?
Sympathetic neurons typically do not use what NT?
Name the 5 pre-vertebral ganglia and what they control
Superior cervical - eyes, salivary glands, heart
Celiac - Stomach, small intestine
Superior mesenteric - small and large intestine
Inferior mesenteric - large intestine, anus, bladder and genitalia
Adrenal medulla - Chromaffin cells of adrenal glands receive direct input from preganglionic sympathetic fibers
Name 4 brainstem nuclei that contain pre-ganglionic neurons and what they control
Eidnger-Westphal nucleus -> ciliary ganglion
Superior salivary nucleus -> pterygopalatine & submandibular gnalgion
Inferior salivatory nucleus -> otic ganglion
Dorsal motor nucleus of vagus -> vagus nerve
Sacral nuclei protect what 3 things via pelvic splanchnic nerves?
Ciliary ganglion control what?
Pupil constriction, lens accomodation
Pterygopalatine ganglion control what?
Lacrimal and salivary glands
Submandibular ganglion control what?
Submandibular gland (Saliva)
Otic ganglion controls what?
Parotid ganglion (saliva)
Nicotinic receptors provide what?
Muscarinic receptors provide what?
Excitatory (smooth muscle, glands)
Where are nicotinic receptors located?
All pre-to-post gnaglionic synapses
Where are muscarinic receptors located?
all parasympathetic-to-effector synpases
some sympathetic-to-effector synpases
What are the 4 types of receptors that bind NE and EPI?
Where are Alpha 1 receptors located?
Vascular smooth muscle
Activation of Alpha 1 receptors results in what?
Alpha 1 receptors have a low affinity for what?
NE and EPI
Where are Alpha 2 receptors located?
Smooth muscle of GI tract
Synapse ofr pre-to-post ganglionic neurons
Activation of Alpha 2 receptors produces what?
Inhibition of firing of post ganglionic neuron
Where are Beta 1 receptors located?
SA and AV node
Activation of Beta 1 reeptors produces what?
Increased HR, increased contractility
Increased saliva secretion
Increased renin secretion
Increased mobilization of lipids for metabolism
What kind of affinity does Beta 1 receptors have for NE and EPI?
Where are Beta 2 receptors located?
Skeletal muscle vasculature
Activation of Beta 2 reeptors results in what?
Relaxation or dilation (inhibition)
Aside from binding their normal NT, receptors are capable of binding what?
Molecules that mimic the action of the normal NT
Receptors can be blocked by agents that:
Bind the receptor but don't activate the receptor
Bind elsewhere but spatially block the receptor
What are some nicotinic agonists?
What are some nicotinic antagonists?
What are some muscarinic agonists?
What are some muscarinic antagonists?