a&p quiz 3 (autonomic nervous system)

What is the function of the parasympathetic division?

"rest-and-digest" - constricts pupils, increases digestive secretions, increases digestive tract smooth muscle activity - stimulates urination and defecation - constricts bronchioles, decreases heart rate EX: feeling sleepy after a big meal

Compare the general effects of the sympathetic and parasympathetic divisions of the ANS. - mental alertness - metabolic rate - digestive/urinary function - use of energy reserves - respiratory rate - heart rate/blood pressure - sweat gland activity

(sympathetic, parasympathetic) - mental alertness: increased, decreased - metabolic rate: increased, decreased - digestive/urinary function: inhibited, stimulated - use of energy reserves: stimulated, inhibited - respiratory rate: increased, decreased - heart rate/blood pressure: increased, decreased - sweat gland activity: stimulated, inhibited

sympathetic chain

- Arises from spinal segments T1-L2 - The preganglionic fibers enter the _sympathetic chain ganglia_ just outside the spinal column

adrenal medullae

- center of the adrenal gland - innervated by preganglionic fibers --> (ACh) - modified sympathetic ganglia (neurons) secrete norepinephrine (NE) and epinephrine (E) into bloodstream, functioning like an endocrine gland - effect is nearly identical to that of the sympathetic postganglionic stimulation of adrenergic synapses

vagus nerve (X)

- the tenth cranial nerve that innervates digestive organs, heart and other areas

collateral ganglia

- unpaired ganglia that receive *splanchnic nerves* from the lower thoracic and upper lumbar segments - postglanglionic neurons innervate abdominopelvic cavity (information about nutrient contents of stomach)

Which fibers are cholinergic vs. adrenergic?

All are cholinergic (preganglionic, postganglionic parasympathetic fibers) EXCEPT for postganglionic sympathetic fibers --> adrenergic

Which fibers have excitatory vs. inhibitory effects?

All fibers are excitatory (preganglionic, postganglionic parasympathetic and sympathetic fibers) except for postganglionic parasympathetic fibers, which effects are EITHER excitatory OR inhibitory, depending on the target cell receptor

Preganglionic parasympathetic fibers travel within which cranial nerves?

III, VII, IX, and X (3, 7, 9, 10)

Which division of the nervous system is less divergent?

Parasympathetic division has less divergence, so effects are more localized

adrenergic

Pertaining to nerves that release the neurotransmitter norepinephrine, or noradrenaline

cholinergic

Referring to cells that use acetylcholine as their synaptic transmitter.

How does the autonomic nervous system differ from the somatic nervous system?

SNS requires only 1 motor neuron from CNS to effector (skeletal muscle), while ANS requires 2 motor neurons from CNS to effector (cardiac and smooth muscle, glands, and fat cells)

Length of pre- and postganglionic fibers in the SYMPATHETHIC vs PARASYMPATHETIC divisions

SYMPATHETIC: short preganglionic fibers, long post PARASYMPATHETIC: long preganglionic fibers, short post

In some severe cases of stomach ulcers, the branches of the vagus nerve (N X) that lead to the stomach are surgically severed. How might this procedure control the ulcers?

Severing the branches of the vagus nerves (N X) helps control stress-induced stomach ulcers by eliminating excessive sympathetic stimulation. Chronic sympathetic stimulation causes constriction of blood vessels, which shuts off the blood supply to the stomach. The reduced blood supply causes cell and tissue death, resulting in ulcers.

Dual innervation mostly have ____ effects.

antagonistic

Dual innervation refers to an organ receiving

both sympathetic and parasympathetic nerves

Where do the preganglionic neurons of the PARASYMPATHETIC division emerge from the spinal cord? (point of CNS origin)

brain stem and sacral spinal region

Postganglionic fibers of autonomic neurons are usually

connected to cardiac muscle, smooth muscle, glands, and adipocytes.

splanchnic nerves

consist of axons that synapse in collateral ganglia; convey information about the nutrient contents of the stomach to the brain

What is the function of the sympathetic division?

fight or flight - increased alertness, metabolic rate, sweating, heart rate, blood flow to skeletal muscle - dilated respiratory bronchioles and pupils - decreased blood flow to digestive organs - E and NE from the adrenal medullae support and prolong the effect (adrenaline)

Effects produced by the parasympathetic branch of the autonomic nervous system include - increased heart rate. - dilation of the pupils. - increased tissue metabolism. - dilation of respiratory passages. - increased secretion by digestive glands.

increased secretion by digestive glands.

Where is the ganglia located in the SYMPATHETIC division?

near spinal cord

Where is the ganglia located in the PARASYMPATHETIC division?

on target organs

The _________ nervous system stimulates cranial nerve ______, which is responsible for slowing the heart rate, constricting the airway, and stimulating digestion.

parasympathetic, X (vagus nerve)

effects of parasympathetic vs sympathetic (location and length of time)

parasympathetic: restricted to specific sites (ONLY visceral structures either serviced by cranial nerves or lying within the abdominopelvic cavity), brief sympathetic: more widespread (reaches visceral and somatic structures), lasts longer

What do preganglionic parasympathetic fibers on the sacral areas form?

pelvic nerves

What are the ganglionic neurons' axons called?

postganglionic fibers

What are the two motor neurons that the ANS uses from CNS to effector?

preganglionic and ganglionic neurons (they communicate)

What does the parasympathetic division consist of?

preganglionic neurons in the brain stem and sacral segments of the spinal cord, and ganglionic neurons in peripheral ganglia located on target organs

What divisions does the autonomic nervous system divide into?

sympathetic and parasympathetic division

What does the sympathetic division consist of?

sympathetic chain ganglia, collateral ganglia, and adrenal medullae

Which of the following fibers usually release norepinephrine (NE)? parasympathetic postganglionic parasympathetic preganglionic somatic sympathetic preganglionic sympathetic postganglionic

sympathetic postganglionic

Where do the preganglionic neurons of the SYMPATHETIC division emerge from the spinal cord? (point of CNS origin)

thoracic and lumbar spinal segments

innervate

to provide neural input or supply with nerves

Almost 75% of all parasympathetic outflow travels along the oculomotor nerve. splanchnic nerves. collateral nerve. vagus nerve. pelvic nerves.

vagus nerve