Cardiac Output, Blood Flow, and Blood Pressure 487| CHECKPOINT
- Explain how stress and a high-salt diet can
contribute to hypertension. Also, explain how
different drugs may act to lower blood pressure.
15a. Using a flowchart to show cause and effect, explain
why a person in hypovolemic shock may have a fast
pulse and cold, clammy skin.
15b. Describe the compensatory mechanisms that act to
raise blood volume during cardiovascular shock.
15c. Explain how septic shock may be produced.
- Describe congestive heart failure and explain the
compensatory responses that occur during this
condition.
Mark’s Crohn’s disease caused him to lose proteins through
the intestine. This produced a fall in plasma protein concen-
tration (hypoproteinemia) and a fall in his plasma oncotic
pressure, so that interstitial fluid was not sufficiently returned
to the vascular system and produced edema. His prolonged
running made him dehydrated, which gave him orthostatic
hypotension that made him dizzy upon standing. He was
advised to drink more and to switch from water to sports
drinks for prolonged exercise sessions, because he needed
to replenish his Na^1 , K^1 , and Cl^2 that were lost in sweat.
This would allow him to maintain his blood volume and pres-
sure, so that his baroreceptor reflex could prevent the ortho-
static hypotension. He later had essential hypertension and
took an ACE inhibitor, which inhibits angiotensin-converting
enzyme, reducing angiotensin-II-induced vasoconstriction
(increasing peripheral resistance) and lowering the total
peripheral resistance. He was advised not to perform the
Valsalva maneuver when lifting heavy weights, to avoid the
fluctuations in heart rate and blood pressure that this pro-
duces, because hypertension is a risk factor for atheroscle-
rosis and coronary heart disease.
See the additional chapter 14 Clinical Investigations on
Orthostatic Hypotension and Pheochromocytoma in the
Connect site for this text.