Reading 5 (103-113)

Question 1

What is the diastolic pressure?

Answer 1

The pressure remaining in the arteries at the end of diastole (diastole is the relaxation phase of the heart)

Question 2

What is MABP?

Answer 2

The avg arterial BP over the cardiac cycle. Not simply arithmetic mean of systolic and diastolic pressures, cause diastole approx 2X duration of systole

Question 3

What is the eqn for MABP involving systolic and diastolic pressure?

Answer 3

MABP = [(systolic pressure – diastolic pressure)/3] + diastolic pressure

Question 4

What is the pulse pressure?

Answer 4

Difference btwn systolic and diastolic pressure

Question 5

What are teleological arguments

Answer 5

Arguments attribute intelligence to body parts like heart e.g. HR inc in order to provide more blood to working muscles. But HR inc cause of neural and/or humoral (i.e. blood-borne molecules e.g. epinephrine) stimuli.

Question 6

What is the more scientific, physiologically correct explanation of arterial BP regulation?

Answer 6

Negative feedback model

Question 7

Where are the baroreceptors located

Answer 7

Aortic arch and in wall of each internal caraotid artery in the caraotid sinus

Question 8

Fxn of baroreceptors?

Answer 8

Send afferent signals to vasomotor centre in medulla oblongata at base of brain

Question 9

What are 5 factors that affects arterial BP?

Answer 9

Posture, exercise, emotional state of subject, fatigue, pain, meals, drugs

Question 10

What precautions must occur when measurements of resting BPs are obtained for clinical purposes?

Answer 10

Patients avoid exertion, exposure to cold, eating, or smoking at least 30 min before measurement, then should rest in quiet room at comfortable temp at least 5 mins w/no postural changes

Question 11

The effect which any factor has on BP is mediated thru 2 mechanism?

Answer 11

CO and TPR. Aka if arterial BP inc, either CO has inc, or TPR has, or both.

Question 12

What is the eqn for MABP in terms of CO and TRP?

Answer 12

MABP = CO x TPR

Question 13

Changes in arterial BP usually compensated w/in ____ by baroreceptors

Answer 13

Seconds

Question 14

Arterial BP may be regulated over longer term by ______.

Answer 14

Kidney

Question 15

How does inc rate of urine output lead arterial BP to dec?

Answer 15

Inc rate or urine output dec total body water, which dec plasma volume. Dec plas volume in CV system will dec pressure distending the walls of arteries, thus dec arterial BP.

Question 16

What are the effects of exercise on BP?

Answer 16

Exercise induces locally mediated vasodilation in active muscle, and a generalized vasoconstriction of non-active skeletal muscles and splanchnic area. Also, HR and myocardial contractility inc, which inc CO.

Question 17

What is involved in mediating the CV and hemodynamic adjustments to exercise?

Answer 17

Central command, the exercise pressor reflex, the arterial baroreflex, and cardiopulmonary baroreflex

Question 18

How does the normal BP response to dynamic exercise differ from normal response to isometric exercise?

Answer 18

• DYNAMIC exercise, SYSTOLIC BP normally RISES w/inc work rate, while DIASTOLIC pressure changes LITTLE. In heavy DYNAMIC exercise, the SYSTOLIC pressure may rise to 200 mmHg.
• ISOMETRIC exercise, BOTH systolic and diastolic pressure normally RISE. Magnitude of the BP response to isometric exercise depends on the amount of muscle mass involved in contraction, the strength of contraction, and whether upper or lower limbs involved. Generally, MABP may inc 20-50mmHg w/isometric am work.