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57 Cards in this Set
- Front
- Back
What do the motor neurons of the Autonomic Nervous System (ANS) do?
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Innervate smooth and cardiac muscle and glands
Operate via subconscious control Involuntary Nervous System |
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What do the majority of the ANS motor neurons effect?
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Viscera
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In what three areas does the ANS differ from the Somatic Nervous System (SNS)?
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Effectors
Efferent pathways Target organ responses |
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What are the effectors of the SNS?
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Skeletal muscels
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What are the 3 specific effectors of the ANS?
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cardiac muscle, smooth muscle, and glands
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What do efferent pathways consist of?
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Heavily myelinated axons of the somatic motor neurons extending from the CNS to the effector (Group A fibers)
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Describe the two-neuron chain of the ANS
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The preganglionic (first) neuron has a thin, lightly myelinated axon and is in the brain or spinal cord
The postganglionic (second) neuron extends to an effector organ, it is thinner and contains no myelin |
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All somatic motor neurons release what neurotransmitter, which has what kind of effect?
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Acetylcholine (ACh)
Excitatory |
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In the ANS, what neurotransmitter(s) do(es) the preganglionic fibers release?
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Acetylcholine (ACh)
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In the ANS, what neurotransmitter(s) do(es) postganglionic fibers release. Is the effect stimulatory or inhibitory?
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Postganglionic fibers release norepinephrine or ACh and the effect is either stimulatory or inhibitory
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ANS effect on the target organ is dependent upon what two things?
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the neurotransmitter released and the receptor type of the effector
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What are the two divisions of the autonomic nervous system?
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sympathetic and parasympathetic
The two divisions counterbalance each other. |
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What does the sympathetic division of the ANS do?
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The sympathetic mobilizes the body during extreme situations (fight or flight).
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What does the parasympathetic division of the ANS do?
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The parasympathetic performs maintenance activities and conserves body energy
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What is the parasympathetic division concerned with?
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keeping body energy use low
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What three activities does the parasympathetic division involve?
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Involves the D activities – digestion, defecation, and diuresis
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Describe the activity of the parasympathetic division in a person who relaxes after a meal.
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Blood pressure, heart rate, and respiratory rates are low
Gastrointestinal tract activity is high The skin is warm and the pupils are constricted |
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What activities does the sympathetic division involve?
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Involves E activities – exercise, excitement, emergency, and embarrassment (lie detector tests monitor the sympathetic reaction)
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During exercise, the sympathetic division does what?
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Promotes adjustments during exercise – blood flow to organs is reduced, flow to muscles is increased
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Describe the sympathetic division's activity in a person who is threatened.
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Heart rate increases, and breathing is rapid and deep
The skin is cold and sweaty, and the pupils dilate |
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Where do the sympathetic divisions fibers originate?
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Thoracolumbar region of the spinal cord
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Describe the length of the sympathetic division's fibers.
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Short preganglionic and long postganglionic
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Where are the ganglia of the sympathetic division located?
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close to the spinal cord
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Where do the parasympathetic divisions fibers originate?
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brain and sacral spinal cord
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Describe the length of the parasympathetic division's fibers.
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Long preganglionic and short postganglionic
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Where are the ganglia of the parasympathetic division located?
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In the visceral effector organs
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Sympathetic Outflow
Where does the sympathetic outflow arise from? |
Arises from spinal cord segments T1 through L2
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Sympathetic Outflow
Where are the sympathetic neurons located in the spinal cord? |
in the lateral horns
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Sympathetic Outflow
Which kind of fibers innervate the numerous organs of the body? |
Postganglionic
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Parasympathetic Outflow: Cranial
What cranial nerve effects the eye |
Occulomotor (III)
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Parasympathetic Outflow: Cranial
What Cranial nerve effects the Salivary, nasal, and lacrimal glands? |
Facial (VII)
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Parasympathetic Outflow: Cranial
What Cranial nerve effects the Parotid salivary glands |
Glossopharyngeal (IX)
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Parasympathetic Outflow: Cranial
What Cranial nerve effects the Heart, lungs, and most visceral organs |
Vagus (X)
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Parasympathetic Outflow: Sacral
What Cranial nerve effects the Large intestine, urinary bladder, ureters, and reproductive organs |
S2-S4
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What three things do the fibers in the pathway to the head do?
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Serve the skin and blood vessels of the head
Stimulate dilator muscles of the iris Inhibit nasal and salivary glands |
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What do the preganglionic fibers in the pathways to the thorax innervate?
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These fibers innervate the heart via the cardiac plexus, as well as innervating the thyroid and the skin
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What do the postganglionic fibers in the pathways to the thorax do?
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Postganglionic fibers directly serve the heart, aorta, lungs, and esophagus
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What five organs do the postganglionic fibers in the pathways to the abdomen innervate?
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Postganglionic fibers serve the stomach, intestines, liver, spleen, and kidneys
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What three organs do the postganglionic fibers in the pathways to the pelvis innervate?
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Postganglionic fibers serve the distal half of the large intestine, the urinary bladder, and the reproductive organs
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What type of pathways do visceral reflexes always contain?
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Polysynaptic
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Where are the afferent fibers of visceral reflexes found?
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in spinal and autonomic nerves
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Identify the receptor, the sensory neuron, the integration center, the motor neurons (both pre and post ganglionic) and the visceral effector
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Describe referred Pain
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Pain stimuli arising from the viscera are perceived as somatic in origin
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What may be the cause of referred pain?
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may be due to the fact that visceral pain afferents travel along the same pathways as somatic pain fibers
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What are the two major neurotransmitters of the Autonomic Nervous System?
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Acetylcholine (ACh) and norepinephrine (NE) are the two major neurotransmitters of the ANS
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In the ANS, ACh is released by all ___________ axons.
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preganglionic
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In the ANS, the only postganglionic axons that release ACh are in the __________ division.
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parasympathetic
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What are cholinergic fibers?
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ACh-releasing fibers
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What are adrenergic fibers
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sympathetic postganglionic axons that release NE
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What determines whether a neurotransmitter effect in the ANS is excitatory or inhibitory?
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The receptor type.
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In the ANS, what are the two types of receptors that bind ACh?
What are they named for? |
nicotinic and muscarinic
These are named after drugs that bind to them and mimic ACh effects |
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Where are the three places that nicotinic receptors are found?
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1.Motor end plates (somatic targets/motor junctions)
2.All ganglionic neurons of both sympathetic and parasympathetic divisions 3.The hormone-producing cells of the adrenal medulla |
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The effect of ACh binding to nicotinic receptors is always _________.
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stimulatory
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Where are muscarinic receptors found?
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Muscarinic receptors occur on all effector cells stimulated by postganglionic cholinergic fibers
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The effect of ACh binding to muscarinic receptors is:
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Either inhibitory or excitatory depending on the receptor type of the target organ.
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What are the two types of adrenergic receptors?
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alpha and beta
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effects of norepinephrine binding to:
alpha receptors is generally _____________. beta receptors is generally _____________. |
stimulatory
inhibitory |