Home › HPCSA Board Exam › Physiology › Blood Vessels and Circulation › A mean arterial pressure held below 60 mm Hg for…
A mean arterial pressure held below 60 mm Hg for an extended period leads to what?
AIschemia, since perfusion of the tissues fails
BHypervolemia, since fluid is retained by kidneys
CPolycythemia, since marrow output rises sharply
DHypertension, since arterioles constrict strongly
Answer & Solution
Correct answer: A. Ischemia, since perfusion of the tissues fails
1. Mean arterial pressure normally sits between 70 and 110 mm Hg.
2. Below 60 mm Hg the driving force is too weak to push blood to and through the tissues.
3. That insufficient flow is ischemia, and inadequate tissue oxygenation, or hypoxia, usually follows it.
4. Neurons tolerate hypoxia poorly and may die if flow is not restored quickly.
5. Hypervolemia and hypertension both describe excess rather than shortfall, so neither fits a falling pressure.
_Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 20 "The Cardiovascular System: Blood Vessels and Circulation", section 20.2 Blood Flow, Blood Pressure, and Resistance_
Related questions
A vessel carrying blood at high pressure close to the heart will have walls that are:The endothelium is described as physiologically critical to regulating capillary exchange Vasoconstriction in arteries occurs when smooth muscle contracts in which layer?In arteries, vasoconstriction makes the lumen narrower and has what effect on blood flow?Endothelins constricting vessel smooth muscle have what effect on blood pressure?The endothelium releases local chemicals called endothelins that can do what to smooth musWhich components of arterial blood pressure are named alongside systolic and diastolic?Which reading is given as a normal adult blood pressure?