Pharmacology Flashcards
Where do parasympathetic neurons leave CNS?
cranial sacral region
Where do sympathetic neurons leave CNS?
thoracolumbar region
Where does synthesis of Epi occur?
adrenal medulla and few epinephrine containing neuronal pathways in brainstem
What is combined to create ACh and by what?
choline combined w/ acetyl from acetyl CoA -> synthesized by ChAT (choline acetyltransferase)
What enzymes facilitates destruction of ACh?
acetylcholinesterase (AChE)
Describe location and function of M2 receptors
located in the heart; slow HR and decrease contractile forces
Describe location and function of M3 receptors
glands (increase secretion), smooth muscle (constriction - bronchoconstriction), endothelium (stimulates NO production -> vasodilation)
Describe location and function of alpha 1 receptors
vascular smooth muscle - vasoconstriction (sympathetics main control of vascular tone)
Describe location and function of beta 1 receptors
cardiac tissue - increases HR and force of contraction
Describe location and function of beta 2 receptors
smooth muscle throughout body - relaxes smooth muscle (vasodilation & bronchodilation)
List the order of catecholamine production and locations
tyrosine -> DOPA -> dopamine -> NE -> Epi tyrosine -> DOPA -> DA occurs in cytoplasm of neurons DA -> NE -> Epi occurs in adrenal medulla (chromaffin cells)
What is the NT and receptors that communicate w/ chromaffin cells?
ACh by preganglionic fibers interact w/ nAChRs on chromaffin cells
What is the major mechanism of termination of catecholamine signaling?
reuptake into nerve terminals by NET (norepinephrine transporter) and DAT (dopamine transporter)
How do blood vessels receive parasympathetic innervation?
smooth muscle of blood vessels NOT innervated by parasympathetics; respond as long as endothelium is intact (activation of mAChRs on endothelial cells causes release of NO -> vasodilation)
Ionotropic vs metabotropic receptors
Ionotropic = opens ligand gated ion channel; Ca or Na depolarize; Cl hyper-polarizes Metabotropic = activates a second messenger system
What is a simple reflex arc?
afferent (sensory) stimulus triggers motor response (to protect us from harm)
Describe a myotatic (stretch) reflex
when muscle is stretched, sensory fiber innervating muscle fires and relays info to spinal cord and enters via dorsal root ganglion; synapses onto alpha motor neuron of muscle and AP travel back to muscle to release ACh and cause contraction of stretched muscle
What types of things cause reflexes in the ANS?
BP, PaCO2, and PaCO2 -> reflexes occur in brain from medulla to hypothalamus and require 2-neuron outflow (pre/post synaptic)
Describe MOA of Digoxin
inhibits Na/K ATPase in cell membrane; affects NCX so that less Ca is removed from cell; more Ca sequestered in SR so increases force of contraction; DOES NOT increase HR
