Final answer:
An increase in sympathetic stimulation from the vasomotor center to blood vessels results in increased vascular resistance, which helps raise blood pressure, particularly following blood loss.
Step-by-step explanation:
An increase in sympathetic stimulation from the vasomotor center to blood vessels will result in increased resistance. The vasomotor center controls the degree of constriction in blood vessels through sympathetic nerve signals. When there's a need to raise blood pressure, such as following blood loss, sympathetic stimulation is enhanced. This leads to vasoconstriction of the arterioles which increases vascular resistance, and also stimulates the release of epinephrine and norepinephrine, further promoting vasoconstriction and elevating cardiac output.
Conversely, when blood pressure is too high, baroreceptors in blood vessels detect this and can trigger an increase in parasympathetic activity while decreasing sympathetic stimulation, leading to vasodilation and reduced resistance. Therefore, a decrease in sympathetic signals causes the vessels to relax, lowering vascular resistance and subsequently blood pressure.