[2.0] Autonomic Nervous System: Control of Visceral Tissue

Maintain body homeostasis and a stable internal body milieu

What is the function of the autonomic nervous system acting with the endocrine system?

Sympathetic, parasympathetic, and enteric nervous systems

What are the three divisions of the autonomic nervous system?

Increase in output of the sympathetic division

What happens to the autonomic nervous system during stress, emergency, physical activity, fear, or excitement?

Increase in output of the parasympathetic division

What happens to the autonomic nervous system during sedentary activity or eating (vegetative behavior)?

Preganglionic neuron and postganglionic neuron

What are the two types of neurons comprising the organization of the ANS?

Intermediolateral cell column in the spinal cord segment T1-L3

Where do sympathetic preganglionic neurons arise from?

Thoracolumbar system

What is another name for the sympathetic nervous system based on its anatomical origin?

Paravertebral ganglia and prevertebral ganglia

Where are sympathetic postganglionic neurons located?

CN III, VII, IX, X and sacral spinal nerves S2-S4

Where do parasympathetic preganglionic neurons arise from?

Craniosacral system

What is another name for the parasympathetic nervous system based on its origin?

Terminal ganglia in or near effector organs

Where are parasympathetic postganglionic neurons located?

Short preganglionic and long postganglionic fibers

What are the relative lengths of sympathetic nerve fibers?

Long preganglionic and short postganglionic fibers

What are the relative lengths of parasympathetic nerve fibers?

Nicotinic acetylcholine receptor (N1) and acetylcholine

What receptor and neurotransmitter are used in the somatic nervous system neuromuscular junction?

Nicotinic acetylcholine receptor (N2) and acetylcholine

What receptor and neurotransmitter are used at autonomic ganglia (both sympathetic and parasympathetic)?

Muscarinic acetylcholine receptor and acetylcholine

What receptor and neurotransmitter are used at parasympathetic target organs?

Alpha and beta adrenergic receptors and norepinephrine

What receptor types and neurotransmitter are used at most sympathetic target organs?

Muscarinic acetylcholine receptors

What is the exceptional receptor type used by sympathetic postganglionic fibers targeting sweat glands?

Acetylcholine

What is the primary neurotransmitter used by sympathetic postganglionic fibers targeting sweat glands?

Chromaffin cells

Which cells within the adrenal medulla release epinephrine into the bloodstream?

Yes

Are preganglionic nerve fibers myelinated?

No

Are postganglionic nerve fibers myelinated?

Odd-numbered muscarinic subtypes (M1, M3, M5)

Which parasympathetic muscarinic receptor subtypes are excitatory to smooth muscle and glands?

Even-numbered muscarinic subtypes (M2, M4)

Which parasympathetic muscarinic receptor subtypes control and inhibit the heart?

Odd-numbered adrenergic subtypes (a1, b1, b3)

Which sympathetic adrenergic receptor subtypes are excitatory?

Even-numbered adrenergic subtypes (a2, b2)

Which sympathetic adrenergic receptor subtypes are inhibitory?

Contraction (mydriasis)

What is the sympathetic response on the radial muscle of the iris?

Contraction (miosis)

What is the parasympathetic response on the sphincter muscle of the iris?

Contraction for near vision

What is the parasympathetic response on the ciliary muscle?

Increased heart rate, contractility, and conduction velocity via b1/b2 receptors

What is the sympathetic response on the heart?

Decreased heart rate, contractility, and conduction velocity

What is the parasympathetic response on the heart?

Relaxation via b2 receptors

What is the sympathetic response on bronchial smooth muscle?

Contraction

What is the parasympathetic response on bronchial smooth muscle?

Decreased motility and tone, contraction of sphincters, and decreased secretion

What is the sympathetic response on the stomach and intestine?

Increased motility and tone, relaxation of sphincters, and stimulation of secretion

What is the parasympathetic response on the stomach and intestine?

Relaxation via b2 receptors

What is the sympathetic response on the gallbladder?

Contraction to release bile

What is the parasympathetic response on the gallbladder?

Relaxation of detrusor and contraction of sphincter

What is the sympathetic response on the urinary bladder?

Contraction of detrusor and relaxation of sphincter

What is the parasympathetic response on the urinary bladder?

Ejaculation via a1 receptors

What is the sympathetic response on male sex organs?

Erection

What is the parasympathetic response on male sex organs?

Contraction of pilomotor muscles (piloerection) via a1 receptors

What is the sympathetic response on skin pilomotor muscles?

Secretion via muscarinic receptors

What is the sympathetic response on sweat glands?

Glycogenolysis via a1 and b2 receptors

What is the sympathetic response on the liver?

Thick, viscous secretion / amylase secretion via b2 receptors

What is the sympathetic response on salivary glands?

Profuse, watery secretion via M3 receptors

What is the parasympathetic response on salivary glands?

Lipolysis via b3 receptors

What is the sympathetic response on adipose tissue?

Myenteric (Auerbach's) plexus and Submucosal (Meissner's) plexus

What are the two major plexuses of the enteric nervous system?

Control of digestive tract motility

What is the primary function of the myenteric plexus?

Regulates gastrointestinal blood flow and epithelial cell function

What is the primary function of the submucosal plexus?