Final answer:
Decreased blood volume causes reduced blood pressure and flow, triggering responses like ADH release and increased heart rate to compensate and maintain vascular volume.
Step-by-step explanation:
When you lose blood volume, there is a decrease in both blood pressure and blood flow. This is similar to how water pressure and flow might reduce in a creek during a dry season. Hypovolemia, or low blood volume, can result from bleeding, dehydration, vomiting, severe burns, or some medications. Upon a loss of 5-10% of blood volume, there is a compensatory increase in ADH (Antidiuretic Hormone) release, which causes vasoconstriction and activation of aquaporin channels, leading to water recovery and restoration of vascular volume. Baroreceptors in the aorta and carotid arteries sense the decreased blood pressure and signal the heart to compensate by increasing its rate and strength of contractions.
For example, when a person loses blood volume due to dehydration or bleeding, the baroreceptors in the body detect the decrease in blood pressure and signal the heart to increase its rate and strength of contractions to compensate for the lowered blood pressure. This increase in cardiac output helps to restore blood pressure to normal levels. Additionally, when blood volume drops, the body releases antidiuretic hormone (ADH) to increase water reabsorption and restore vascular volume.