Ganong's Review of Medical Physiology, 23rd Edition

268 SECTION III Central & Peripheral Neurophysiology
TABLE 17–1 Responses of some effector organs to autonomic nerve activity. (Continued)
Uterus Variable α 1 Contraction (pregnant)
is the innervation of salivary glands. Parasympathetic activation
causes release of watery saliva, while sympathetic activation
causes the production of thick, viscous saliva.
The two divisions of the ANS can also act in a synergistic or
cooperative manner in the control of some functions. One
example is the control of pupil diameter in the eye. Both sympathetic
and parasympathetic innervations are excitatory, but
the former contracts the radial muscle to cause mydriasis and
the latter contracts the sphincter (or constrictor) muscle to
cause meiosis. Another example is the synergistic actions of
these nerves on sexual function. Activation of parasympathetic
nerves to the penis increases blood flow and leads to
erection while activation of sympathetic nerves to the penis
causes ejaculation.
There are also several organs that are innervated by only one
division of the ANS. In addition to the adrenal gland, most
blood vessels, the pilomotor muscles in the skin (hair follicles),
and sweat glands are innervated exclusively by sympathetic
nerves. The lacrimal muscle (tear gland), ciliary muscle (for
accommodation for near vision), and the sublingual salivary
gland are innervated exclusively by parasympathetic nerves.
β 2
Relaxation
Male sex organs Erection α 1 Ejaculation
Skin
Pilomotor muscles — α 1 Contraction
Sweat glands — α 1 Slight, localized secretion b
M Generalized abundant, dilute
secretion
Liver — α 1, β 2 Glycogenolysis
Pancreas
Exocrine glands Increases secretion α Decreases secretion
Endocrine glands — α 2 Inhibits secretion
Salivary glands Profuse, watery secretion α 1 Thick, viscous secretion
β Amylase secretion
Lacrimal glands Secretion —
Sympathetic Nervous System
Effector Organs Parasympathetic Nervous System Receptor Type Response
Adipose tissue — α 2, β 3 Lipolysis
a
A dash means these cells are not innervated by this division of the autonomic nervous system.
b
On palms of hands and in some other locations (“adrenergic sweating”).
Modified from Hardman JG, Limbird LE, Gilman AG (editors): Goodman and Gilman’s The Pharmacological Basis of Therapeutics, 10th ed. McGraw-Hill, 2001.
PARASYMPATHETIC CHOLINERGIC
& SYMPATHETIC
NORADRENERGIC DISCHARGE
In a general way, the functions promoted by activity in the
cholinergic division of the autonomic nervous system are
those concerned with the vegetative aspects of day-to-day living.
For example, parasympathetic action favors digestion and
absorption of food by increasing the activity of the intestinal
musculature, increasing gastric secretion, and relaxing the pyloric
sphincter. For this reason, the cholinergic division is
sometimes called the anabolic nervous system.
The sympathetic (noradrenergic) division discharges as a
unit in emergency situations and can be called the catabolic
nervous system. The effects of this discharge prepares the individual
to cope with an emergency. Sympathetic activity dilates
the pupils (letting more light into the eyes), accelerates the
heartbeat and raises the blood pressure (providing better perfusion
of the vital organs and muscles), and constricts the
blood vessels of the skin (which limits bleeding from wounds).