Autonomic Nervous System**
Part of nervous system; composed of sympathetic and parasympathetic nervous systems
Autonomic Nervous System**
Exerts control over many organ functions and tissues in body; innervates visceral organs, glands, blood vessels
Autonomic Nervous System**
Controls/regulates function of visceral organs; has afferent/efferent pathways
Autonomic Nervous System: Efferent Fibers**
Cell bodies in spinal cord; reach sympathetic ganglia on both sides of vertebral column
Autonomic Nervous System: Parasympathetic Efferent Fibers**
Reach ganglia at/near organs
Sympathetic System**
Prepares and mobilizes the body in an emergency
Sympathetic System Stimulation*
Inc heart rate, constriction of arterioles of skin + intestine, inc BP, dilation of pupils, sphincters close, hair stands, sweat
Parasympathetic System**
Conserves and stores energy
Parasympathetic System Stimulation*
Dec in heart rate, pupil constriction, inc peristalsis, inc glandular activity, sphincters open, bladder wall is contracted
Pheochromocytoma**
Tumor of adrenal medulla; secretes excessive amounts of catecholamines; inc excretion of VMA
Sympathetic Origin*
Thoraco-lumbar; cell bodies lie on lat horn of T1-L2/3
Parasympathetic Origin*
Cranio-sacral; CN III, VII, IX, X and S1, S2, S3 (pelvic splanchic nerve)
Sympathetic: Efferent Outflow*
Cell bodies lie at lat. horn of T1-L2/3 spinal cord
Sympathetic Receptors*
Adrenergic; alpha receptors a1 a2; beta receptros b1 b2; dopamine receptors D1 D2
Parasympathetic Receptors*
Cholinergic; nicotinic, muscarinic
Neurotransmitters: Adrenergic
Neurons release norepinephrine
Neurotransmitters: Cholinergic
Neurons release ACH; both sympathetic and parasympathetic
Neurotransmitters: Peptidergic
Neurons in parasympathetic release peptides; ie vasoactive inhibitory peptide and substance P
Adrenergic Receptors: Alpha-1*
Located on vascular smooth muscle of skin/splanchic regions, GI/bladder sphincters, radial muscle of iris
Adrenergic Receptors: Alpha-1*
Produce excitation (constriction, contraction); equally sensitive to norepinephrine
+ epinephrine (
high enough concentration to activate alpha 1)
Adrenergic Receptors: Alpha-1 Mechanism*
G protein stimulator, Phospholipase C, formation of IP3, inc in Ca+
Adrenergic Receptors: Alpha-2*
Located in preseynaptic nerve terminal, platelets, fat cells, walls of GI tract; produce inhibition (relaxation/dilation)
Adrenergic Receptors: Alpha-2 Mechanism*
G protein alpha inhibitor, inhibition of adenylate cyclase, dec in CAMP
Adrenergic Receptors: Beta-1*
Located in SA/AV node and ventricular muscle of heart; excitation (inc heart rate, conduction velocity, contractility)
Adrenergic Receptors: Beta-1*
Sensitive to norepinephrine and epinepthrine; more sensitive alpha-1 receptors
Adrenergic Receptors: Beta-1 Mechanism*
Activation G protein alpha simulator, activation adenylate cyclase, inc in CAMP
Adrenergic Receptors: Beta-2*
Located on vascular smooth skeletal muscle, bronchial smooth muscle, walls of GI tract and bladder
Adrenergic Receptors: Beta-2*
Relaxation (dilation of smooth muscles/bronchioles, relaxation of bladder); more sensitive to epinephrine
Adrenergic Receptors: Beta-2 Mechanism*
Activation G protein alpha stimulator, activation adenylate cyclase, inc in CAMP
Cholinergic Receptors: Nicotinic*
Located in autonomic gang of symp/parasymp at NMJ + adrenal medulla; activated by ACH/nicotine
Cholinergic Receptors: Nicotinic*
produce excitation; blocked by ganglionic blockers in autonomic ganglia (not at NMJ)
Cholinergic Receptors: Nicotinic Mechanism*
ACH binds to alpha subunits of nicotinic ACH receptor; nicotinic ACH receptors are ion channels for Na+ and K+
Cholinergic Receptors: Muscarinic*
Located in heart, smooth muscle, glands; inhibitory in heart (dec HR, conduction velocity)
Cholinergic Receptors: Muscarinic*
Excitatory in smooth muscle/glands (inc GI motility, inc secretion); activated by ACH/muscarine; blocked by atropine
Cholinergic Receptors: Muscarinic Mechanism-Heart*
Inhibition of adenylate cyclase; opening of K+, slows rate of spontaneous Phase 4 depolarization; dec HR
Cholinergic Receptors: Muscarinic Mechanism- Smooth Muscle/Glands
Formation of IP3; inc in intracellular (Ca2+)
Preganglionic Neurotransmitters
ACH
Postganglionic Neurotransmitters: Parasympathetic
ACH
Postganglionic Neurotransmitter: Symapthetic
Norepinephrine
Alpha-1
Postsynaptic; located on vascular, pupillary, and pilomotor smooth muscle
Alpha-1: Vascular smooth muscle Action
Contraction
Alpha-1: Pupillary Smooth Muscle Action
Contraction, mydriasis
Alpha-1: Pilomotor smooth muscle Action
Contraction, erects hair
Alpha-2
Presynaptic; located on adrenergic/cholinergic nerve terminals, fat cells, platlets, and smooth muscle
Alpha-2: Adrenergic/Cholinergic Nerve Terminals Action
Inhibits transmitter release
Alpha-2: Fat cells
Inhibits lipolysis
Alpha-2: Platelets Action
Stimulates aggregation
Alpha-2: Smooth Muscle Action
Contraction
Beta-1
Located in heart; stimulates rate and force
Beta-2
Located in vasscular, bronchial, and GI tract (smooth muscle), liver, and Pancreatic B cells
Beta-2: Vascular, Bronchial, GI Tract (smooth Muscle Action
Relaxes
Beta-2: Liver Action
Stimulates Glycogenolysis
Beta-2: Pancreatic B Cells Action
Stimulates insulin increase
Muscarinic
Positive effect IN GLANDS AND SMOOTH MUSCLE (except vascular); Negative effect IN HEART
Muscarinic Mechanism
Increased intracellular calcium
Nicotinic
At the neuromuscular junction; excitation-opens Na/K channels; depolarization
Pupil: Sympathetic
Alpha receptor, dilation
Pupil: Parasympathetic
Constriction
Ciliary Muscle: Sympathetic
Beta receptor; accomodation
Ciliary Muscle: Parasympathetic
Contration
Lacrimal Gland: Sympathetic
Dec secretion
Lacrimal Gland: Parasympathetic
Inc sec
Salivary Glads: Sympathetic
Alpha receptor; activates viscous secretion
Salivary Glands: Parasympathetic
Activates secretion of watery saliva
Parotid: Sympathetic
Vasoconstrictor
Parotid: Parasympathetic
Activates secretion of watery saliva
Sublingual: Sympathetic
Decreased secretion
Sublingual: Parasympathetic
Increase secretion
Heart: Sympathetic*
Beta-1 receptor; positive chronotropic and dromotropic
Heart: Parasymapthetic*
Negative chronotropic and dromotropic
Coronary Arteries: Sympathetic*
Vasodilation
Coronary Arteries: Parasympathetic*
Vasoconstriction
Bronchi Muscle: Sympathetic*
Beta-2 receptor; dilation
Bronchi Muscle: Parasympathetic*
Conctrictor
Lung Vessels: Sympathetic*
Constriction
Lung Vessls: Parasympathetic*
Dilation
Lung Glands: Sympathetic*
Dec secretion
Lung Glands: Parasympathetic*
Inc secretion
Peristalsis: Sympathetic*
Beta-2 receptor; relaxation
Peristalsis: Parasymapthetic*
Activation
GI Sphincters: Sympathetic*
Alpha receptor; constriction
GI Sphincters: Parasympathetic*
Relaxation
GI Glands: Sympathetic*
Dec secretion
GI Glands: Parasympathetic*
Inc secretion
Liver: Sympathetic*
Beta receptor; gluconeogenesis
Live: Parasympathetic*
Glycogenesis
Gall Bladder Sphincters: Sympathetic*
Beta-2 receptor; relaxation
Gall Bladder Sphincters: Parasympathetic*
Constriction
Pancreas-Insulin: Sympathetic*
Alpha receptor = inhibits its secretion; beta receptor = activates its secretion
Pancreas-Exocrine: Sympathetic*
Alpha receptor inhibits secretion
Pancreas-Exocrine: Parasympathetic*
Activates secretion
Adrenal Medulla*
Sympathetic; activates secretion
Urinary Bladder-Sphincter: Sympathetic*
Alpha receptor; contraction
Urinary Bladder-Spinchter: Parasympathetic*
Relaxation
Urinary Bladder-Detrusor M: Sympathetic*
Beta receptor; relaxation
Urinary Bladder- Detrusor M: Parasympathetic*
Contraction
Uterus-Pregnant: Sympathetic*
Alpha receptor; contraction
Uterus-Not Pregnant: Sympathetic*
Beta receptor: relaxation
Genitals: Sympathetic
Ejaculation/emission
Genitals: Parasympathetic
Erection/vasodilation