CH 16 Autonomic Nervous System Overview and Functions

Are signals from the visceral motor neurons in ANS involved in conscious or subconscious control of visceral functions?

Subconscious

List four visceral effectors.

Smooth muscle, cardiac, adipose, glands

Where in the brain are the integrative centers for autonomic activity located?

Hypothalamus

What are preganglionic neurons?Why are they called preganglionic?

Visceral motor neurons in the brain stem and spinal cord, They extend to the ganglia

What are the axons of preganglionic and postganglionic neurons referred to as?

Preganglionic fibers and postganglionic fibers

What are postganglionic neurons?

Visceral motor neurons in peripheral ganglia

Where do postganglionic neurons synapse?

Target organs

When does the sympathetic division of the ANS predominate?

Fight or flight

When does the parasympathetic division of the ANS predominate?

Rest and digest

What is another name for the sympathetic division of the ANS?

Thoracolumbar division

What is another name for the sympathetic division of the ANS? Why is it called this?

Thoracolumbar; preganglionic neurons are located between T1 and L2 vertebrae

Which ANS division has short preganglionic fibers and long postganglionic fibers?

Sympathetic

Where do sympathetic preganglionic neurons synapse?

Sympathetic chain ganglia, Collateral ganglia, Adrenal medulla

What structures are targeted when synapsing in sympathetic chain ganglia?

body wall, thoracic cavity head, neck, or limbs

What is in the white rami communicantes?

Myelinated preganglionic fibers

What is in the grey rami communicantes?

Unmyelinated postganglionic fibers

What structures are targeted by collateral ganglia?

cervical, lumbar, and sacral spinal nerves 

What are the three collateral ganglia?

Celiac, superior mesenteric, inferior mesenteric

What does the celiac ganglion innervate?

stomach, liver, gallbladder,  pancreas, and spleen

What does the superior mesenteric ganglion innervate?

Small intestine and pancreas

What does the inferior mesenteric ganglion innervate?

kidneys, bladder, terminal segments of the large intestine and sex organs 

What neurotransmitters are released by adrenal medulla cells?

Epinephrine and norepinephrine

What neurotransmitter do sympathetic preganglionic neurons release?

ACh

What neurotransmitter do they release in the adrenal medulla?

ACh and norepinephrine

What neurotransmitter do parasympathetic preganglionic neurons release?

Para pre neurons release ACh

Which synapses use acetylcholine?

Cholinergic

What is the effect of cholinergic synapses on ganglionic neurons?

Excitatory

What are varicosities?

Swollen axon segments with neurotransmitter vesicles

Most sympathetic postganglionic neurons release which neurotransmitter?

Norepinephrine

What are neurons that release norepinephrine called?

Adrenergic

Which enzymes break down norepinephrine?

Monoamine oxidase and catechol-o-methyltransferase

What are the two types of adrenergic receptors?

Alpha and beta receptors

What neurotransmitter is released at nitroxidergic synapses?

Nitric oxide

What is another name for the parasympathetic division? Why is it called that?

Craniosacral division; Preganglionic neurons are in brainstem and spinal segments S2-S4

Which ANS division has long preganglionic and short postganglionic fibers?

Parasympathetic

Parasympathetic fibers innervate which body regions?

Cranial, trunk, and pelvic regionl

Which cranial nerve carries ~75% of parasympathetic outflow?

Vagus nerve

Which neurotransmitter is released by all parasympathetic neurons?

all parasympathetic neurons release ACh

Name two types of cholinergic receptors.

Nicotinic and muscarinic

What binds to nicotinic receptors?

Nicotine (from tobacco)

What binds to muscarinic receptors?

Muscarine (from poison mushrooms)

Why are sympathetic responses more widespread than parasympathetic?

one sympathetic preganglionic fiber can innervate several ganglia at the same time, para pre can only do 1 at a time 

 - neurotransmitters are released into the blood stream instead of the synapse, they are carried around the body and dont have contact w enzymes that break them down 

What is an autonomic plexus?

Network of sympathetic postganglionic and parasympathetic preganglionic fibers

What is autonomic tone?

Spontaneous activity in resting motor neurons

What is the difference between long and short visceral reflexes?

Long: involves CNS, Short: completely bypasses CNS and occurs in autonomic ganglia

Which part of the brain stem contains centers and nuclei involved with salivation, swallowing, digestive secretions, peristalsis, and urinary function?

Medulla Oblangata

What is memory consolidation?

Conversion of short-term to long-term memory

What limbic system structures are essential for memory consolidation?

Amygdala and hippocampus

Which sleep stage includes active dreaming?

REM (Rapid Eye Movement)

What brain structure wakes you from sleep?

Reticular activating system

Prozac and Celexa affect which neurotransmitter?

Serotonin (by slowing reuptake)

What illness is linked to excessive dopamine?

Schizophrenia

What disease is caused by insufficient dopamine?

Parkinson's

What is the most debilitating form of senile dementia?

Alzheimer's