Lecture 7 Flashcards
CNS?
Brain + Spinal Cord
PNS?
-Everything outside of CNS
1) Somatic: Voluntary control of skeletal muscle
2) Autonomic: Involuntary control of viscera (Sympathetic (“fight or flight”)) (Parasympathetic (“rest, digest, and repair”))
Somatic?
Voluntary control of skeletal muscle
Autonomic?
-Involuntary control of viscera
-Sympathetic (“fight or flight”)
-Parasympathetic (“rest, digest, and repair”)
Autonomic NS - Sympathetic Divison?
-Paravertebral Ganglia lay close to spinal cord
-PRE-Ganglionic Neurons: Short cholinergic (ACh) projections leave CNS to innervate ganglia
-POST-Ganglionic Neurons: Long adrenergic (NE) projections leave ganglia to innervate effector (exception: kidney has dopaminergic innervation)
(Autonomic NS - Sympathetic Divison)
PRE-Ganglionic Neurons?
Short cholinergic (ACh) projections leave CNS to innervate ganglia
(Autonomic NS - Sympathetic Divison)
POST-Ganglionic Neurons?
Long adrenergic (NE) projections leave ganglia to innervate effector (exception: kidney has dopaminergic innervation)
Autonomic NS - Parasympathetic Division?
-Pre-Ganglionic Neurons: Long cholinergic projections which innervate ganglia NEAR target organ (CN X (Vagus) is one of the most important)
-Post-Ganglionic Neurons: Short cholinergic projections to target organ
-All projections of parasympathetic division are cholinergic
(Autonomic NS - Parasympathetic Division)
Pre-Ganglionic Neurons?
Long cholinergic projections which innervate ganglia NEAR target organ (CN X (Vagus) is one of the most important)
(Autonomic NS - Parasympathetic Division)
Post-Ganglionic Neurons?
Short cholinergic projections to target organ
Dual Innervation?
-Most organs receive dual innervation (sympathetic + parasympathetic)
-Human Eye
(Blood vessels, hair follicles, and sweat glands DO NOT receive parasympathetic innervation)
Human Eye has?
-Dual Innervation
1) Sympathetic- Radial muscle contracts dilating pupil
2) Parasympathetic- Circular muscle contracts constricting pupil
(Cholinergic Synapse Locations)
Acetylcholine (ACh) Metabolism?
-Precursosrs: choline + acetyl CoA
-Enzyme: choline acetyltransferase (ChAT)
-Terminated: hydrolysis by acetylcholinesterase (AChE)
(Cholinergic Synapse Locations)
Cholinergic Receptor Subtypes + Locations?
-Locations:
(All pre-ganglionic neurons (para. and sym.) are cholinergic) (All post-ganglionic neurons of para. are cholinergic) (All somatic (skeletal muscle) neurons are cholinergic)
-Subtypes:
1) Nicotinic Receptors (Ligand-gated (FAST)) (Nm and Nn)
2) Muscarinic Receptors (G-Protein Coupled (SLOW)) (M1,M2,M3,M4,M5)
All pre-ganglionic neurons (para. and sym.) are?
Cholinergic
All post-ganglionic neurons of Parasympathetic are?
Cholinergic
All somatic (skeletal muscle) neurons are?
Cholinergic
(Cholinergic Synapse Locations)
Nicotinic Acetylcholine Receptors?
-Found in ganglia + skeletal muscle (FAST transmission via ligand-gated ion channels)
-Nicotine, DMPP, and Epibatidine are nicotinic agonists
(Cholinergic Synapse Locations)
Nicotinic Acetylcholine Receptor Agonists?
-Nicotine
-DMPP
Epibatidine
(Cholinergic Synapse Locations)
(Nicotinic Acetylcholine Receptor)
Nm?
-Location: NMJ
-Physiological Response: Skeletal muscle contraction
(Cholinergic Synapse Locations)
(Nicotinic Acetylcholine Receptor)
Nn?
-Location: Autonomic ganglia, brain
-Physiological Response: Ganglionic transmission
(Cholinergic Synapse Locations)
Muscarinic Acetylcholine Receptors?
-Almost exclusively in post-ganglionic neurons of parasym. system (cardiac and smooth muscle, gland cells, nerve terminals)
-Some post-ganglionic neurons of sym. nervous system (sweat glands, vascular smooth muscle)
-Muscarine, Pilocarpine, and Oxotremorine are muscarinic agonists
(Cholinergic Synapse Locations)
Muscarinic Acetylcholine Receptor Agonists?
-Muscarine
-Pilocarpine
-Oxotremorine
(Cholinergic Synapse Locations)
Muscarinic Acetylcholine Receptor Agonists?
-Muscarine
-Pilocarpine
-Oxotremorine
(Cholinergic Synapse Locations)
Muscarinic Acetylcholine Receptors (Odd)?
(Modulate parasym. response)
-Odd numbered Muscarinic receptors = EXCITATORY
-Elevate intracellular [Ca2+]
(Cholinergic Synapse Locations)
Muscarinic Acetylcholine Receptors (Odd)?
(Modulate parasym. response)
-Odd numbered Muscarinic receptors = EXCITATORY
-Elevate intracellular [Ca2+]
(Muscarinic Receptor Subtype) M1?
-Location: Nerves
-Physiological Response: Depolarization of neuron
(Muscarinic Receptor Subtype) M3?
-Location: Glands, smooth muscle, endothelium, nerves
-Physiological Response: Contraction of GI and bronchial smooth muscle, increase GI secretions
(Muscarinic Receptor Subtype) M5?
-Location: CNS
-Physiological Response: Modulate neuroexcitability and vascular tone
(Muscarinic Receptor Subtype) M5?
-Location: CNS
-Physiological Response: Modulate neuroexcitability and vascular tone
(Cholinergic Synapse Locations)
Muscarinic Acetylcholine Receptors (Even)?
-Even numbered Muscarinic receptors = INHIBITORY
-Inhibit Adenylyl Cyclase = Decrease cAMP
(Cholinergic Synapse Locations)
Muscarinic Acetylcholine Receptors (Even)?
-Even numbered Muscarinic receptors = INHIBITORY
-Inhibit Adenylyl Cyclase = Decrease cAMP
(Muscarinic Receptor Subtype) M2?
-Location: Heart, nerves, smooth muscle
-Physiological Response: Decreased SA node firing rate (negative chronotropic) Decreased Ventricular contractile force (negative inotropic)
(Adrenergic Synapse Locations (Sympathetic))
NE Metabolism?
-Dopamine synthesized from tyrosine by enzyme tyrosine hydroxylase
-Dopamine transported into vesicle by VMAT2
-Dopamine beta-hydroxylation (DbetaH) to NE
-Action Terminated:
1) Reuptake into pre-synaptic terminal
2) Catabolized by MAO-A and COMT
(Adrenergic Synapse Locations (Sympathetic))
Adrenergic Receptor Subtypes + Locations?
-Locations: (post-ganglionic neurons of SNS) (cardiac and smooth muscle, gland cells, nerve terminals)
-Subtypes:
1) Alpha Receptors (GPCR)
2) Beta Receptors (GPCR)
(Adrenergic Synapse Locations (Sympathetic))
Alpha Adrenergic Receptors?
(Modulate a sym. response)
-Alpha 1 resemble odd muscarinic ACh
-Alpha 2 resemble even muscarinic ACh receptors
(Adrenergic Synapse Locations (Sympathetic))
a1?
-Some Biochemical Effectors: Increased intracellular Ca2+
-Location: vascular smooth muscle, Heart, liver
-Physiological Response: Vasoconstriction, increased contractile force, glycogenolysis, gluconeogenesis
(Adrenergic Synapse Locations (Sympathetic))
a2?
-Some Biochemical Effectors: Inhibit adenylyl cyclase
-Location: pancreas islets (beta cells)
-Physiological Response: Decreased Insulin secretion
(Adrenergic Synapse Locations (Sympathetic))
Beta Adrenergic Receptors?
-All beta adrenergic receptors INCREASE cAMP via activation of Adenyl cyclase
-Role of cAMP: (Increases contraction of Heart (B1)) (Decreases contraction (relaxes) vascular and bronchial smooth muscle (B2))
(Adrenergic Synapse Locations (Sympathetic))
B1?
-Location: Heart, juxtaglomerular cells
-Physiological Response: Increased force and rate of contraction, Increased renin secretion
(Adrenergic Synapse Locations (Sympathetic))
B2?
-Location: Smooth Muscle (vascular, bronchial, GI) bronchial glands, liver
-Physiological Response: Relaxation (vasodilation, bronchodilator)
(Nested Loops)
Function of the ANS is to?
Preserve homeostasis, there are several “layers” that ensure if one fails, another can step in
(Nested Loops)
Function of the ANS is to?
Preserve homeostasis, there are several “layers” that ensure if one fails, another can step in
(Nested Loops)
(Brain)
Amygdala?
-While brainstem, is the primary region of homeostasis, there are several “higher centers” of control such as amygdala (associates ANS responses to specific behaviors (ex. shock)) (ex. loud sounds triggers “fight or flight”)
(Nested Loops)
(Brain)
Baroreceptor Reflex?
-Sensory afferent neurons that help modulate control based on various internal stimuli (ex. chemo and mechano receptors)
(Nested Loops)
Spinal Cord?
-Sensory neurons at dorsal root ganglion send signal to spinal cord (which innervates bladder) and trigger voiding
-Spinal cord injury and MS may negative affect this loop
(Nested Loops)
Ganglion?
-Ganglia on the surface of organs can modulate function to some extent
(ganglia on Heart contribute to rhythmicity) (CHF and arrhythmias can be associated with failure of this loop)
(Nested Loops)
Synapses?
-Presence of heteroreceptors at neuronal synapse allows for regulation of synaptic signaling
-Heteroreceptors act as terminal receptors for other transmitters that may act either to stimulate or inhibit release at that terminal
