Module 5- PNS Flashcards
Fibers responsible for proprioception
A-alpha and A-beta
Sensation of throbbing pain, touch, and temperature
Type C
Fibers carrying sensations of sharp, prickling pain and temperature
A-delta
Sympathetic and parasympathetic pre ganglionic fibers are what type
Type B
Post ganglionic sympathetic fibers are what type
Type B
Sympathetic outflow arises where
T1-L3
Cardioaccelerator fibers arise where
T1-T4
Signs and symptoms of Horner’s syndrome
Miosis Ptosis Anhydrosis Enophthalamos Flushing Increased skin temperature Nasal congestion
Horners syndrome is caused by
Block at stellate ganglion
Sympathetic preganglionic neurons arise where in SC
Intermediolateral horn
All SNS preganglionic fibers pass through what rami
White rami communicans in route to paravertebral ganglia
Some SNS preganglionic fibers pass through what additional rami. Significance
Gray ramus
Distributed to all spinal nerves from the ganglia
Allow coordinated, mass discharge of SNS
Stimulation of presynaptic A2 receptors what happens
NE synthesis and release is decreased
NEGATIVE FEEDBACK
Synthesis of epi
Tyrosine - L dopa - dopamine - NE - epi
NE receptor complex causes activation of what
Adenylate cyclase = increased production of cAMP
Termination of acts of NE
1- 80% reuptake
2- metabolism by MAO in synaptic cleft
3- metabolized by COMT in plasma
Patient taking MAOI should avoid
Ephedrine and Demerol
Both trigger release of NE
Adrenergic receptor found on presynaptic nerve terminals of sympathetic postganglionic neurons and in tissues on postsynaptic membranes in brainstem and peripheral tissues.
Inhibitory
Alpha 2
Adrenergic receptors found peripherally in a variety of tissues innervated by sympathetic postganglionic neurons
Excitatory response generally
Arterial and venous vasoconstriction
Alpha 1
Adrenergic receptors found in heart, kidney, and adipose tissue
Excitatory
Beta 1
Adrenergic receptor found in smooth muscle and glandular tissue
Inhibitory- dilation
Glycogenolysis and gluconeogenesis
Beta 2
Stimulation results in increased insulin secretion
Beta 2
Stimulation results in decreased insulin secretion
Alpha 1&2
Stimulates Na-K pump
Beta 2
Uterine relaxation
Contraction
Relax beta 2
Contract alpha 1
Increased renin release
Beta 1
2 important stimuli for aldosterone release
Angiotensin II and high serum potassium
Increases potassium secretion and increases sodium reabsorption
Aldosterone
Renin release occurs in response to
Decreased renal blood pressure and increased SNS activity, and Chloride
Ritrodine is a beta 2 agonist used to treat preterm labor side effects
Hyperglycemia
Hypokalemia
Tachycardia
It does cross the placenta so fetal effects may be seen
Long acting non selective alpha adrenergic agonist used to control BP in pt with pheochromocytoma
Phenoxybenzamine
Selective alpha 2 adrenergic antagonist used to treat impotence
Yohimbe
Selective alpha 1 adrenergic antagonist that lowers BP without increaseing release of NE (because does not. Block alpha 2)
Prazosin
Non selective beta 2 agonists
Avoid in pt with irritable airway bc B2 block can cause bronchoconstriction
Propanolol Timolol Esmolol Nadolol Pindolol
Mixed alpha and beta adrenergic antagonists
Labetalol
Carvedilol