Chapter 17

cranial and sacral parasympathetic fibers release ? at their corresponding ganglion

Ach

cranial and sacral parasympathetic fibers release? at their visceral effectors

Ach

sympathetic fibers release ? at their corresponding ganglion (paravertebral or collateral ganglion)

Ach

What are the two ways that the parasympathetic division innervates its target organs?

The preganglionic axons in cranial nerves III (oculomotor), VII (facial) , and IX (glossopharyngeal) travel a comparative long distances before finally synapsing in terminal ganglia. Cranial nerve X (vagus), and the pelvic nerves do not synapse on any external ganglia, but instead synapses within each target organ in intramural ganglia.

The effects of epinephrine and norepinephrine released by the suprarenal glands last longer than those of either chemical when released at neuroeffector junctions. Why?

There are no enzymes to break down epinephrine and norepinephrine in the blood and very little in peripheral tissues.

the white ramus communicans

carries the preganglionic fibers into a nearby sympathetic chain ganglion

sympathetic ganglia in the sympathetic division of the ANS send postganglionic fibers to

target organs

In some severe cases, a person suffering from stomach ulcers may need to have surgery to cut the branches of the vagus nerve that innervates the stomach. How would this help the problem?

Cutting off autonomic nervous system stimulation to the stomach through the vagus nerve decreases stimulation of digestive glands, this reducing their secretion. This may diminish ulcers in the wall of the stomach.

sympathetic fibers release ? at their visceral effectors

NE

what are the four ways the sympathetic division innervates its target organs?

Some postganglionic fibers do not return back to the spinal nerves but instead pass directly to their target organs through specific sympathetic nerves. Some preganglionic neurons pass right through the sympathetic chain ganglia to pass to what are called collateral ganglia. These are anterior to the vertebral column. Usually single rather than paired. Obviously a longer preganglionic fiber is necessary to reach these ganglia. In only one case, the preganglionic neuron extends its axon through the sympathetic chain ganglia, through the celiac ganglion and directly into the adrenal medulla (center of the adrenal gland.) Here it synapses on specialized neural cells that act more as an endocrine gland. When stimulated by the preganglionic neurons these cells release epinephrine (adrenaline) and norepinephrine into a network of capillaries. Some go through the sympathetic chain ganglia?

this is secreted into general circulation when the sympathetic division is stimulated

epinephrine

preganglionic fibers in the ANS parasympathetic division are sent to

ganglia in or near the target organ

splanchnic nerves

include preganglionic fibers that go to collateral ganglia

Paravertebral ganglia belong to what division of the ANS

sympathetic division

preganglionic fibers in the ANS sympathetic division are sent to

sympathetic ganglia

What anatomical mechanism is involved in blushing?

sympathetic stimulation relaxes vessel walls, increasing blood flow to the skin

post ganglionic fibers of autonomic neurons are usually

?

Why are the effects of the parasympathetic stimulation more specific and localized than those of sympathetic division?

The parasympathetic division innervates only visceral structures served by some cranial nerves or lying within the thoracic and abdominopelvic cavities. The sympathetic division has widespread impact due to extensive collateral branching of preganglionic fibers, which reach visceral organs and tissues throughout the body.

Compare the general effects of the sympathetic and parasympathetic divisions of the ANS

The sympathetic stimulates metabolism, increases alertness and prepares for emergency in fight or flight. The parasympathetic promotes relaxation, nutrient uptake, and energy storage in rest and repose.

The neurotransmitter at all synapses and neuroeffector junctions in the parasympathetic division of the ANS is

acetylcholine

all preganglionic autonomic fibers release ? at their synaptic terminals, and the effects are alway ?

acetylcholine, excitatory

this is released at neuroeffector junctions when the sympathetic division is stimulated (not acetylcholine) and also secreted into the general circulation

norepinephrine

what are the two classes of sympathetic receptors that stimulate alpha receptors and beta receptors

norepinephrine and epinephrine

the large cells in the suprarenal medulla, which resemble neurons in sympathetic ganglia

release epinephrine and norepinephrine into blood capillaries

visceral motor neurons in the CNS

send axons to synapse on peripherally located ganglionic fibers. (they are not ganglionic neurons, are not in the dorsal root ganglion, and do not have unmyelinated axons except in the lower thoracic region)

sympathetic preganglionic fibers are characterized as being

short in length and myelinated

preganglionic fibers of the ANS sympathetic division originate in the

thoracolumbar division

cutting the ventral root of the spinal nerve at L2 would interrupt the transmission of what type of information?

voluntary motor output and ANS motor output