Sympathetic Nervous System quiz #1 Flashcards
Sympathetic Nervous System quiz #1
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What are the main physiological effects of the sympathetic nervous system during a fight or flight response?
The sympathetic nervous system increases heart rate, blood pressure, and airflow, dilates pupils, stimulates sweat glands, releases glucose from the liver, causes vasodilation in skeletal muscles, vasoconstriction in visceral vessels, decreases gastrointestinal activity, and contracts arrector pili muscles (causing goosebumps). Describe the analogy of the sympathetic nervous system as a subway system and explain the roles of the spinal cord, sympathetic trunk, ganglia, and effectors in this analogy.
In the subway analogy, nerve impulses are trains, nerve fibers are tracks, the spinal cord is the central terminal, the sympathetic trunk is a parallel track, ganglia are train stations where synapses (train changes) occur, and effectors (organs/glands) are the destinations. From which spinal cord segments do sympathetic preganglionic fibers originate, and what is the significance of this region?
Sympathetic preganglionic fibers originate from spinal cord segments T1 to L2, known as the thoracolumbar region, which is responsible for initiating the sympathetic (fight or flight) response. Explain the difference in length between preganglionic and postganglionic fibers in the sympathetic nervous system and the reason for this arrangement.
In most sympathetic pathways, preganglionic fibers are short because they synapse in ganglia close to the spinal cord, while postganglionic fibers are long as they travel from the ganglia to distant effector organs. What are the three main pathways by which sympathetic preganglionic fibers can synapse with postganglionic fibers?
Sympathetic preganglionic fibers can synapse at the same level in the sympathetic trunk ganglion, at a higher or lower level in the trunk, or pass through the trunk without synapsing to reach a collateral ganglion (as splanchnic nerves). What are splanchnic nerves, and how do their fiber lengths differ from typical sympathetic fibers?
Splanchnic nerves are sympathetic preganglionic fibers (arising from T5-L2) that bypass the sympathetic trunk to synapse in collateral ganglia near abdominal organs. In this pathway, preganglionic fibers are long and postganglionic fibers are short, which is the opposite of the usual sympathetic pattern. Describe the role of the adrenal medulla in the sympathetic nervous system and its unique innervation.
The adrenal medulla is only innervated by sympathetic preganglionic fibers. When stimulated, it releases epinephrine and norepinephrine (adrenaline and noradrenaline) into the bloodstream, amplifying the fight or flight response. It acts as a modified sympathetic ganglion. What is the function of the white and gray rami communicantes in the sympathetic nervous system?
The white ramus communicans carries myelinated preganglionic fibers from the spinal nerve to the sympathetic ganglia, while the gray ramus communicans carries unmyelinated postganglionic fibers from the ganglia back to the spinal nerve for distribution to effectors. What are two major changes in blood flow that occur during sympathetic nervous system activation in a fight or flight response?
Blood flow increases to skeletal muscles through vasodilation and decreases to visceral organs through vasoconstriction. In the subway analogy for the sympathetic nervous system, what do the ganglia and effectors represent?
Ganglia represent train stations where synapses (train changes) occur, and effectors are the final destinations (organs or glands) affected by the nerve impulses.
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