Lecture 9 Flashcards
Somatic motor system
Release only ACh, Only stimulates, neurons directly innervate effector
Autonomic motor system
2 sets of neurons, release ACh or Norepinephrine, autonomic neurons can stimulate or inhibit
Sympathetic division
Thor columnar region, presynaptic releases ACh, postsynaptic releases NE or E, ganglia close to CNS, effects last longer, more divergence- preganglionic branch and synapse at any level allowing mass activation
Parasympathetic division
Craniosacral region, pre and postsynaptic release ACh, ganglia close to target, effects don’t last long, minimal divergence
Adrenal medulla
Innovated directly by preganglionic sympathetic neurons, secretes E and NE when stimulated by sympathetic nervous system as part of mass activation
Most sympathetic postganglionic
Norepinephrine (adrenergic)
Alpha adrenergic receptors
More sensitive to NE, use Ca2+ second messenger
Alpha 1 receptor
Stimulates vasoconstriction, dilates pupils
Alpha 2 receptor
Found on presynaptic terminals to regulate amount of NE released negative feedback)
Beta adrenergic receptor
More sensitive to E, uses cAMP as second messenger
Beta 1 receptor
Increases heart rate and contractility
Beta 2 receptor
Promotes vasodilation and bronchodilation
Hypertension drugs
Propranalol old blocks beta 1 and 2 lowers blood pressure but also causes bronchoconstriction and asthma
New atenolol selective for beta 1
New clonidine stimulates alpha 2 suppressing sympathoadrenal system to lower BP
Asthma drugs
Epinephrine old stimulates beta 1 receptors in heart and beta 2 in airways
Terbutaline new more selective for B2
Cold medicine
Phenylephrine, alpha 1 promotes vasoconstriction of nasal mucosa
Nicotinic ACh receptors
Found in autonomic ganglia, stimulated by ACh from preganglionic neurons, serve as ligand-gated channels for Na+ and K+
Blocked by curare
Muscarinic ACh receptors
Found in visceral organs, stimulated by ACh from postganglionic neurons, can be stimulator or inhibitory opening or closing K+ or Ca2+ channels, use g-protein and second messengers, blocked by atropine
Body temp
Mostly sympathetic regulated via blood vessels and sweat glands
Sympathetic only innovation
Adrenal medulla, arrector pili, sweat glands in skin, most blood vessels
