Peripheral Nervous System Flashcards
Parasympathetic neuron
Long pre
Short post
ACh at both junctions
Sympathetic neuron
Short pre synapses in autonomic ganglion with ACh
Long post on target organ with NE
Except in sweat glands, ACh (not NE) released at post
Sympathetic neuron to adrenal medulla
ACh released on adrenal medulla
Adrenal medulla secretes 80% epi, 20% NE (made by chromaffin cells)
% hormones secreted by pheo
20% NE
80% epi
Muscarinic receptor in PNS
Postganglionic parasympathetic neurons
Sympathetic post ganglionic at exocrine sweat glands
G protein coupled=slower response
Nicotinic receptors in PNS
Motor end plate of skeletal muscle In sympathetic chain on postganglionic In synapse of parasympathetic Ligand gated receptor=fast response Needs to ACh attached Na rushes into cell
A alpha
Muscle length and force, proprioception, somatic nerves
Large diameter and fast conduction
A beta
Proprioception, touch, pressure
A gamma
Skeletal muscle tone
A delta
Pain, temperature, touch
Sensory afferent
B
Autonomic functions
Preganglionic autonomic neurons
sC
Postganglionic sympathetic neurons
Various autonomic functions
Nonmyelinated
dC
Sensory afferent
Various autonomic functions
Pain, temp, touch
Nonmyelinated
Sympathetic outflow comes from
T1-L2 or T1-L3
Cardiacaccelerator fibers come from
T1-T4
Stellate ganglion
Formed from inferior cervical and 1st thoracic ganglia
Horner syndrome
Due to stellate ganglion block Ptosis Mitosis (smaller pupil) Anhydrosis Flushing of skin Stuffy nose Enopthalmos Increased skin temp *on ipsilateral side
Agents that should be avoided in pt taking MAO inhibitor
Indirect acting sympathomimetic agents- ephedrine and meperidine
Would release excess amounts of NE and may cause hypertensive crisis
Meperidine usually has more problems than ephedrine
Alpha 1 receptor
Vascular smooth muscle and glands
Promotes arterial and venous vasoconstriction
Increases systemic arterial blood pressure
Alpha 2 receptor
Presynaptic nerve terminals- negative feedback
Brainstem- inhibits sympathetic nervous system outflow
Substantial gelatinosa of spinal cord- promotes analgesia
Beta 1 receptors
Heart, kidney, and adipose tissue
Increased heart rate and contractility which increases blood pressure
Beta 2 receptors
Smooth muscle and glandular tissue
Causes smooth muscle dilation- promotes bronchodilation and relaxation of pregnant uterus
Stimulates glycogenolysis and gluconeogenesis to increase blood glucose
Stimulates Na K pump- promotes hypokalemia
Control of resting BP
Renin
Most important stimulus for aldosterone release
Angiotensin II
High serum potassium
Causes of renin release
Decreased renal blood pressure
Increased sympathetic nervous system activity
Labetolol beta to alpha block
7:1
interactions of anesthetics with beta blockers
From worst to best Ketamine- increases SVR in beta blocked heart Enflurane Halothane Opioids Isoflurane=Sevoflurane=Desflurane
Sympathetic blockade in a spinal
2-6 dermatomes higher than sensory block
Parasympathetic nervous system arises from
(Craniosacral flow) CN 3-oculomotor (midbrain) CN 7- facial (pons) CN 9-glossopharyngeal (medulla) CN 10-vagus (majority of parasympathetic flow) (medulla) S2-4
Ecothiophate
Treats glaucoma
Succ and mivacurium contraindicated
Would increase length of action due to plasma cholinesterase inhibition
Cholinergic syndrome
Mnemonic: DUMBELL STPD Diarrhea Urination Mitosis Bradycardia Bronchoconstriction Emesis Lacrimation Lethargy Salivation Seizures Treatment is atropine Pralidoxime Diazepam
