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Flashcards in ANS Ch 16 Deck (45):
1

ANS

System of motor neurons that innervates smooth and cardiac muscles and glands. Also called involuntary or visceral motor system.

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Two neuron chain

ANS uses two neurons to reach the effector unlike the CNS that uses only one

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Preganglionic neuron

First neuron whose body lies lies within the brain or spinal cord, it synapses with the second motor neuron.

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Post ganglioninc neuron

Second motor neuron whose cell body is within the autonomic ganglion outside the CNS.

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2 autonomic neurotransmitters

Acetylcholine
Epi and Nor Epi

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Autonomic postganglionic fibers release?

Epi and Nor Epi
Secreted by most sympathetic fibers

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Parasympathetic fibers release

ACh

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Dual Innervation

Two divisions of the ANS--sympathetic and parasympathetic--balance each other out
Some organs only receive sympathetic stimulation but vital organs have both.

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Parasympathetic

Rest and digest:
Craniosacral: originate in brain and sacrum
Long preganglion short post ganglion fibers
Ganglion are close to organ served

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Sympathetic

Fight or flight:
Thoracolumbar: originate in thoracic and lumbar
Short preganglion and long post ganglion fibers
Ganglion are close to spinal cord

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Cranial Part

Oculomotor (III)
Facial (VII)
Glossopharyngeal (IX)
Vagus (X)

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Oculomotor nerve

Innervated the smooth muscles of the eye that causes the pupil to constrict and lens to bulge. Synapse in the ciliary ganglia

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Facial nerves

Activate nasal glands and lacrimal glands: pterygopalatine ganglia
Stimulate sublingual salivary glands: submandibular ganglia

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Glossopharyngeal nerves

Synapse in the otic ganglia. Activate parotid salivary glands anterior to the ears

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Vagus Nerve

Account for 75% or preganglionic parasympathetic fibers and innervate virtually every thoracic and abdominal oregan

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Sacral Part

Serves pelvic organs and distal half of the intestines. S1-S4 forn the pelvic splanchnic nerves.

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Sympathetic Division

Arise from T1 - L2,
Thoracolumbar division

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3 locations of sympathetic ganglionic neurons

Sympathetic chain ganglia (paravertebral)
Collateral ganglia (prevertebral)
Adrenal medulla (release neurotransmitters into the blood stream)

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Cholinergic fibers

Fibers that release ACh, effects are always excititory

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Adernergic fibers

Fibers that release NE,

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Cholinergic receptors

ACh binding receptors
Nicotinic
Muscarinic

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Nicotinic Receptors

Ach receptor
Affects are always stimulatory
Found on all postganglionid neurons both sympathetic and parasymathetic
Neuromuscular junctions

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Muscarinic Receptors

Ach receptor
Either inhibitory or stimulatory
Cardiac=slows
Smoth muscle=increases

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Adenergic receptors

NE Binding Receptors
Alpha
Beta

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NE and Epinephrine

Can be either excitatory or inhibitory
depending on target organ

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Sympathetic or vosomotor tone

Partial continual blood vessal constriction, dilate slightly and constrict slightly to maintain BP

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Parasympetheitc tone

Slows heart rate and dictates normal activity in the digestive and urinary tracts

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Uniquely sympathetic functions

Thermoregulatory responce to heat
Release of Renin from Kidneys
Metobolic rate regulation

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Localized affects

Parasympatheitc only has localized affects

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Localized and Diffuse affects

Parasympathetic is both
NE is not hydrolysed as fast as ACh
NE and Epinephrine are released into the boold streem by the Adrenal glands and have a longer lasting effect.

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Brain stem and spinal cord controls

Most direct influence over ANS

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Hypothalammus

"Boss"
Acting through the ANS it coordinated heart activity, BP, body temp, water ballance and endocrine activity. When there is an emotional sterss signal from limbic system the hypothalamas activates the ANS

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Bio Feedback

Becoming aware of physiological conditions with the goal of continual influence

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Visceral relexes

Have two neurons in motor componant

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Alpha

a 1 are the most common: stimulate G protein activation and cause a realease of intracellular calcium from ER
a2 results with lowering cyclic - AMP in the cytoplasm

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Beta

Effects skeletal muscles, heart, lungs, and liver.
G protein activation increases the cyclic- AMP in the cytoplasm
B1: increases metabolic activity
B2: causes inhibition respiratory passageways dilate
B3: lipolysis

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3 collateral ganglia

ciliac
superior mesenteric
inferior mesenteric

38

Sympathetic Division Summary

2 sets of chain ganglia- on each side of spinal cord
3 collateral ganglia- one anterior and two to the adrenal medulla
Preganglionic fibers are short
Post ganglionic fibers are longer
All preganglionic neurons release Ach
Most post ganglionic neurons release NE but a few release Ach or NO.

39

Two types of parasympathetic ganglia

Terminal: located near the target tissue
Intramural: embedded in the target tissue

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4 cranial ganglia of the parasympathetic

Pterygopalatine
Ciliary
Submandibulr
Otic

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Summary of the Parasympathetic Division

Visceral motor nuclei associated with cranial nerves III, VII, IX and X and sacral segments S1-S4
Ganglia are located proximal or in the target organ
All parasympathetic neurons are cholinergic
Contain either Nicotinic receptors or Muscarinic receptors (excitement of inhibition)
Stimulation is breif and restricted to specific organs

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6 autonomic plexus'

cardiac
pulmonary
esophageal
ciliac
inferior mesenteric
hypogastric

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Autonomic tone

Background level of activity in which both sympathetic and parasympathetic divisions innervate. This provides a grater range of control options because of the opposing effects of the two systems. Small amounts of Ach and NE are released contimuously.

44

Visceral reflex arc

Consists of a receptor, a sensory neuron, a processing center (one or more interneurons) and two visceral motor neurons.
Long reflex: the processing step involves an interneuron within the CNS
Short reflex: Bypass the CNS - synapse in autonomic ganglia outside the spinal cord

45

Cellular mechanisms of memory formation

Increase in neurotransmitters
Facilitation at synapse
Formation of additional synaptic connections