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17 Cards in this Set
- Front
- Back
Peripheral Nervous System Divisions
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PNS---->1. Sensory Division (afferent) [a). somatic sensory & b.) visceral sensory]
---------->2. Motor Division (efferent) [a. somatic nervous system & b.) autonomic nervous system {i. sympathetic division & ii. parasympathetic division}] |
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Peripheral Nervous System: Autonomic Nervous System
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-Only motor nerves with motor neurons
-Only innervate smooth muscle, cardiac muscle, and glands -involuntary -regulates VISCERAL MOTOR FUNCTIONS (heart rate, digestion, blood pressure, urination) -maintains homeostasis by either increasing or decreasing activity |
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Autonomic System Divisions: Parasympathetic & Sympathetic Divisions
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-Sympathetic Nervous System---speeds up activity (fight or flight); inenrvates smooth muscle in walls of blood vessels [vasoconstriction], heart pumps blood harder)
-Parasympathetic Nervous System---slows down activity; most active when body is at rest; "rest & digest" |
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Motor Division of Peripheral Nervous System
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-Somatic nervous system (voluntary)---skeletal muscles; *single* neuron innervating muscle
-Autonomic nervous system (involuntary)---smooth muscle, cardiac muscle, glandular epithelium; *two* neurons innervating muscle |
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Details on Somatic (voluntary) Nervous System
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-single axon (ONE neuron innervating muscle)
-cell bodies ONLY in CNS -innervates skeletal muscle -voluntary -each somatic motor neuron runs from the CNS, all the way to the muscle being innervated -each somatic motor neuron consists of a single neuron plus the skeletal muscle cells that it innervates -typical somatic motor axons are thick, heavily myelinated fibers that conduct nerve impulses rapidly |
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Details on Autonomic Nervous System
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-includes pre & post-ganglionic neurons (TWO motor neurons innervating muscle)
-cell bodies found inside AND outside CNS -involuntary |
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Ganglion
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in the autonomic nervous system, it is a clump of cell bodies outside the CNS
-autonomic ganglia are MOTOR ganglia containing cell bodies of motor neurons |
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Pre-ganglionic neuron
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-part of motor unit in ANS
-myelinated -cell body found within CNS -smooth muscle -travels to ganglion, its preganglionic axon then synapses w/ post-ganglionic neuron -functionally, the preganglionic neuron signals the postganglionic neuron -includes WHITE RAMUS COMMUNICANS |
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Post-ganglionic neuron
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-unmyelinated
-part of motor unit in ANS -larger diameter -voluntary/somatic motor axon (skeletal muscle) -slower signal transmission -ravels to effector visceral organs: cardiac muscle, smooth muscle, glandular epithelium, adipose tissue -includes GRAY RAMUS COMMUNICANS |
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Sympathetic vs. Parasympathetic
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-these two divisions of the ANS arise from different regions of the CNS
-the PREGANGLIONIC axon terminals of both divisions BOTH RELEASE ACETYLCHOLINE -Sympathetic division is aka the THORACOLUMBAR division bc its fibers emerge from the thoracic & superior lumbar parts of the spinal cord -----sympathetic pathways have SHORT PRE-ganglionic neurons & LONG POST-ganglionic neurons; sympathetic fibers branch profusely -------SYMPATHETIC POSTGANGLIONIC NEURONS RELEASE NOREPINEPHRINE (NOADRENALINE); adregenic effects -Parasympathetic division is aka the CRANIOSACRAL division bc its fibers emerge from the brain and the sacral spinal cord -----parasympathetic have LONG PRE-ganglionic neurons & SHORT POST-ganglionic neurons -PARASYMPATHETIC POSTGANGLIONIC NEURONS RELEASE ACETYLCHOLINE |
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Sympathetic:
THORACOLUMBAR Trunk Ganglia (aka paravertebral ganglia) |
-pre-ganglionic neurons exit spinal cord through ventral root from T1-L2, go into spinal nerve to reach ganglia (VIA WHITE RAMI); then axon for 2nd postganglionic neuron leaves via GRAY rami
-paravertebral ganglia joined to ventral rami of nearby spinal nerves by white & gray rami communicantes -preganglionic is WHITE rami -post ganglionic is GRAY rami |
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Parasympathetic:
CRANIOSACRAL |
-4 cranial nerves (III, VII, IX, X)
-sacral spinal nerves (S2-S4) -cranial outflow of parasympathetic division originates from sacral spinal cord and supplies the rest of the abdominal organs and the pelvic organs |
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BIG PICTURE OF THORACOLUMBAR VS CRANIOSACRAL
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-Thoracolumbar---SPEEDS UP
-Craniosacral---SLOWS DOWN -BOTH INNERVATE THE SAME STRUCTURES |
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Terminal Ganglia
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NOT located next to spinal cord, they're found ON or NEAR the effector organ
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PARASYMPATHETIC LENGTH OF FIBERS
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-LONG PRE-GANGLIONIC
-SHORT POST-GANGLIONIC |
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SYMPATHETIC LENGTH OF FIBERS
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-SHORT PRE-GANGLIONIC
-LONG POST-GANGLIONIC |
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Effects of autonomic stimulation
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-The eye:
---sympathetic: pupils dilate, increase activity ---parasympathetic: pupils constrict -Glands: ---sympathetic: increase sweat, decrease saliva ---parasympathetic: increase tears, inecrease saliva -Heart: ---sympathetic: increase HR ---parasympathetic: decrease HR -Blood vessels: ---sympathetic: vasoconstriction, increase BP ---parasympathetic: vasodilation? (muscle in blood vessels can only make them smaller, no real effect on venous side) -Lungs: ---sympathetic: dilation of bronchioles ---parasympathetic: constriction of bronchioles (don't need all lung capacity) -GI tract: ----sympathetic: sphincters closed (humans different animals) ---parasympathetic: sphincter closing inhibited |