Final answer:
After severe hemorrhage, compensatory responses include increased heart rate and cardiac output, vasoconstriction, and release of epinephrine and norepinephrine.
Step-by-step explanation:
In response to severe hemorrhage, the body initiates compensatory responses to maintain blood pressure and restore blood volume. These responses include:
- Increase in heart rate and cardiac output: The cardiovascular centers stimulate sympathetic responses to increase heart rate, boosting cardiac output and maintaining blood flow. This restores cardiac output to normal levels and helps increase blood pressure.
- Vasoconstriction: The arterioles constrict, leading to an increase in vascular resistance, while constriction of the veins increases venous return to the heart. Both of these steps help increase blood pressure.
- Release of epinephrine and norepinephrine: Sympathetic stimulation triggers the release of these hormones, which enhance cardiac output and vasoconstriction. This further assists in maintaining blood pressure.