184
Chapter 6
Table 6–11
Some Effects of Autonomic Nervous System Activity
Effector Organ
Receptor Type*
Sympathetic Nervous System Effect
Parasympathetic Nervous
System Effect†
Eyes
Iris muscle
a
1
Contracts radial muscle (widens pupil)
Contracts sphincter muscle
(makes pupil smaller)
Ciliary muscle
b
2
Relaxes (fl attens lens for far vision)
Contracts (allows lens to become
more convex for near vision)
Heart
SA node
b
1
Increases heart rate
Decreases heart rate
Atria
b
1
,
b
2
Increases contractility
Decreases contractility
AV node
b
1
,
b
2
Increases conduction velocity
Decreases conduction velocity
Ventricles
b
1
,
b
2
Increases contractility
Decreases contractility slightly
Arterioles
Coronary
a
1
,
a
2
Constricts
b
2
Dilates
Skin
a
1
,
a
2
Constricts
Skeletal muscle
a
1
Constricts
b
2
Dilates
Abdominal viscera
a
1
Constricts
Kidneys
a
1
Constricts
Salivary glands
a
1
,
a
2
Constricts
Dilates
Veins
a
1
,
a
2
Constricts
b
2
Dilates
Lungs
Bronchial muscle
b
2
Relaxes
Contracts
Salivary glands
a
1
Stimulates watery secretion
Stimulates watery secretion
b
Stimulates enzyme secretion
Stomach
Motility, tone
a
1
,
a
2
,
b
2
Decreases
Increases
Sphincters
a
1
Contracts
Relaxes
Secretion
(?)
Inhibits (?)
Stimulates
Intestine
Motility
a
1
,
a
2
,
b
1
,
b
2
Decreases
Increases
Sphincters
a
1
Contracts (usually)
Relaxes (usually)
Secretion
a
2
Inhibits
Stimulates
Gallbladder
b
2
Relaxes
Contracts
Liver
a
1
,
b
2
Glycogenolysis and gluconeogenesis
Pancreas
Exocrine glands
a
Inhibits secretion
Stimulates secretion
Endocrine glands
a
2
Inhibits secretion
b
2
Stimulates secretion
Fat cells
a
2
,
b
3
Increases fat breakdown
Kidneys
b
1
Increases renin secretion
Urinary bladder
Bladder wall
b
2
Relaxes
Contracts
Sphincter
a
1
Contracts
Relaxes
Uterus
a
1
Contracts in pregnancy
Variable
b
2
Relaxes
Reproductive tract
(male)
a
1
Ejaculation
Erection
Skin
Muscles causing hair erection
a
1
Contracts
Sweat glands
a
1
Secretion from hands, feet, and armpits
AChR
Generalized abundant, dilute secretion
Table adapted from “Goodman and Gilman’s The Pharmacological Basis of Therapeutics,” Laurence L. Brunton, John S. Lazo, and Keither L. Parker, eds., 11th ed., McGraw-Hill, New York, 2006.
*Note that many effector organs contain both alpha-adrenergic and beta-adrenergic receptors. Activation of these receptors may produce either the same or opposing effects. For simplicity, except for the
arterioles and a few other cases, only the dominant sympathetic effect is given when the two receptors oppose each other.
†These effects are all mediated by muscarinic receptors.
‡A dash means these cells are not innervated by this branch of the autonomic nervous system or that these nerves do not play a signifi cant physiological role.
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