If there is an increase in stimulation from the sympathetic nervous system, in general what impact will it have on vasomotor tone, peripheral resistance and MAP?
If there is an increase in stimulation from the sympathetic nervous system, it will generally have the following impact on vasomotor tone, peripheral resistance, and mean arterial pressure (MAP):
1. Vasomotor tone: Sympathetic stimulation causes vasoconstriction, which increases vasomotor tone. Increased sympathetic activity leads to the contraction of smooth muscles in the blood vessel walls, narrowing the diameter of the blood vessels and increasing their resistance to blood flow.
2. Peripheral resistance: Increased sympathetic activity and vasoconstriction lead to an increase in peripheral resistance. Peripheral resistance refers to the resistance encountered by the blood as it flows through the systemic circulation. Increased vasoconstriction causes the resistance to blood flow in the arteries to increase, resulting in heightened peripheral resistance.
3. Mean arterial pressure (MAP): The MAP is directly influenced by the interaction of cardiac output and peripheral resistance. When sympathetic activity increases, as in a fight-or-flight response, there is greater vasoconstriction and an increase in peripheral resistance. This results in an increase in MAP since more force is required for the heart to pump blood against the higher resistance.
In summary, an increase in sympathetic nervous system stimulation leads to increased vasomotor tone, elevated peripheral resistance, and an overall rise in mean arterial pressure.