Question

select the terms in each blank to accurately complete the sentences describing how the ans controls organs without dual innervation. 1. many blood vessels only have innervation from the (click to select) division of the ans. 2. to regulate blood pressure, the nerve fibers maintain a baseline degree of vessel constriction, called (click to select) tone. 3. if there is a drop in blood pressure, the sympathetic neurons fire, increasing smooth muscle (click to select) in the vessel. 4. the diameter of the vessel (click to select), which (click to select) the pressure inside the vessel. 5. conversely, if there is an increase in blood pressure, a drop in sympathetic firing frequency will (click to select) the smooth muscles and (click to select) the lumen, decreasing pressure.

Explanation:

1. Many blood vessels have only sympathetic innervation. The sympathetic division of the ANS plays a major - role in regulating blood vessels.
2. Vasomotor tone is the baseline degree of vessel constriction maintained by nerve fibers to regulate blood pressure.
3. When blood pressure drops, sympathetic neurons fire, causing smooth - muscle contraction in the vessel to increase blood pressure.
4. When smooth - muscle contracts, the vessel diameter decreases, which increases the pressure inside the vessel.
5. When blood pressure increases, a decrease in sympathetic firing frequency relaxes the smooth muscles and dilates the lumen, decreasing pressure.

Answer:

1. Sympathetic
2. Vasomotor
3. Contraction
4. Decreases, Increases
5. Relax, Dilate