Download Guided Lecture Notes

Guided Lecture Notes, Porth
Chapter 23: Disorders of Blood Pressure Regulation
Learning Objective 1: Define the terms systolic blood pressure, diastolic blood
pressure, pulse pressure, and mean arterial blood pressure.

Describe to the students the mechanisms of pressure generation, ventricular
contraction, and vessel resistance. Explain the contraction phase leading to
systolic pressure and the resting phase of diastolic pressure. When talking about
pulse pressure and mean arterial pressure, make sure to emphasize the
continuous driving pressure. (PowerPoint slide 2)
Learning Objective 2: Explain how cardiac output and peripheral vascular resistance
interact in determining systolic and diastolic blood pressure.

Explain how the mean arterial pressure is the driving pressure that is generated
by ventricular ejection (stroked volume  heart rate) and vascular smooth muscle
contraction. Have the students envision constantly flowing blood with a mean
driving pressure. (PowerPoint slide 3)
Learning Objective 3: Describe the mechanisms for short-term and long-term
regulation of blood pressure.

Explain to the students how blood pressure changes as needed. When they stand
up, sit down, or walk up stairs, CO will go up, and therefore if unchecked, blood
pressure would rise. To counter this, we have short-term regulation via neural
(baroreceptor reflex) and humoral (chemoreception) mechanisms. Explain how
pressure changes are instantly recognized by the baroreceptors and how changes
in PaCO2 and PaO2 are monitored in the medulla for rapid recognition. Explain
how long-term regulation is handled by the renal system via blood volume.
(PowerPoint slide 4)
Learning Objective 4: Describe the requirements for accurate and reliable blood
pressure measurement in terms of cuff size, determining the maximum inflation
pressure, and deflation rate.

In the process of describing the generation of systolic and diastolic pressure,
incorporate into the discussion the methodology of measuring blood pressure.
Describe how the brachial artery is compressed by the sphygmomanometer by
inflating the cuff. To ensure full compression, the cuff must be the appropriate
size for the patient (PowerPoint slides 5, 6)
Learning Objective 5: Cite the definition of hypertension put forth by the seventh
report of the Joint National Committee on Detection, Evaluation, and Treatment of
Hypertension.

Explain the definition and relate it to normal physiology. (PowerPoint slide 10).
Learning Objective 6: Differentiate essential, systolic, secondary, and malignant forms
of hypertension.

Begin by explaining the concept of heightened blood pressure (learning
objective 5), exploring each contributing component. Then describe how the
different types of hypertension arise from alterations of these mechanisms.
(PowerPoint slides 12, 13)
Learning Objective 7: Describe the possible influence of genetics, age, race, obesity,
diet and sodium intake, and alcohol consumption on the development of essential
hypertension.

Explain how physiologic factors and behavior factors will affect each of the
components of blood pressure. For example, chronic alcohol use affects systolic
pressure more than diastolic pressure. (PowerPoint slides 14, 15)
Learning Objective 8: Cite the risks of hypertension in terms of target organ damage.

Explain how hypertensive damage is usually related to damage to small blood
vessels. Organs that require extensive blood flow are very susceptible to damage.
(PowerPoint slide 16)
Learning Objective 9: Describe behavior modification strategies used in the prevention
and treatment of hypertension.

Explain that modifications in lifestyle and drug treatments will counter the
pathological changes that affect blood pressure. Drugs will counter vessel
constriction, decreased salt intake will decrease blood volume, exercise will
improve vascular efficiency, etc. (PowerPoint slides 17, 18)
Learning Objective 10: List the different categories of drugs used to treat hypertension
and state their mechanisms of action in the treatment of high blood pressure.

Explain the mechanism of each hypertensive drug. For example, diuretics act by
decreasing blood volume. (PowerPoint slide 17)
Learning Objective 11: Explain the changes in blood pressure that accompany normal
pregnancy and describe the four types of hypertension that can occur during pregnancy.

Describe the massive changes that take place in a woman’s body during
gestation. Explain how the demands of the fetus and the physiologic changes
significantly increase the demands on the system. (PowerPoint slides 22, 23)
Learning Objective 12: Cite the criteria for the diagnosis of high blood pressure in
children.

Explain to the students that children are much different from adults for numerous
physiologic reasons. Therefore, the criteria for hypertension are more specific
for age, height, and weight. (PowerPoint slide 24)
Learning Objective 13: Define systolic hypertension and relate the circulatory changes
that occur with aging that predispose to the development of systolic hypertension.

Define systolic hypertension as a systolic pressure of 140 mm Hg or greater and
a diastolic pressure of less than 90 mm Hg. Describe how systolic pressure often
rises with age.
Learning Objective 14: Define the term orthostatic hypotension.

Describe the normal baroreceptor response and how changes in position are
compensated for by changes in CO and vascular resistance. Then describe the
process of orthostatic hypotension as a defective baroreceptor reflex.
(PowerPoint slide 25)
Learning Objective 15: Describe the cardiovascular, neurohumoral, and muscular
responses that serve to maintain blood pressure when moving from the supine to
standing position.

Explain to the students the baroreceptor reflex, chemoreceptor reflex, and the
skeletal muscle pump, as well as venous valves actions. Incorporate all these
mechanisms into the regulation of blood pressure. Then describe how these
mechanisms compensate simultaneously when changing position. (PowerPoint
slide 27)
Learning Objective 16: Explain how fluid deficit, medications, aging, disorders of the
ANS and bed rest contribute to the development of orthostatic hypotension.

Have the students revisit the factors involved in blood pressure maintenance and
how each of these disturbances would cause decreases in blood pressure when
changing position. (PowerPoint slides 27, 28)