18-3: Regulation and measurement of blood pressure

Question 1

Neural regulation of blood pressure counteracts moment-by-moment fluctuations in BP by altering ___.

Answer 1

peripheral resistance

Question 2

vasomotor center

Answer 2

clusters of sympathetic neurons in the medulla whose function is to control the diameter of blood vessels, especially arterioles.

Question 3

The vasomotor center transmits impulses along _ _ neurons into __.

Answer 3

sympathetic motor neurons; smooth muscle in vessel walls

Question 4

vasomotor tone

Answer 4

VC sends steady rate of impulses resulting in a constant state of mild vasoconstriction

Question 5

vasoconstriction

Answer 5

VC increases the # of impulses sent, increasing blood pressure

Question 6

vasodilation

Answer 6

VC decreases the # of impulses sent, lowering blood pressure

Question 7

In vasoconstriction, a(n) ___ # of impulses are sent, __ blood pressure; in vasodilation, a(n) __ # of impulses are sent, __ blood pressure.

Answer 7

increased; increasing; decreased; lowering

Question 8

Vasomotor activity is modified by inputs from where?

Answer 8

baroreceptors, chemoreceptors, higher brain centers

Question 9

baroreceptors

Answer 9

pressure receptors in the wall of the aorta and carotid sinuses that send impulses to the vasomotor center as well as the cardiac center in the medula

Question 10

What is the affect of increased blood pressure on the baroreceptors?

Answer 10

increased BP > stretches baroreceptors > inhibits VC

less sympathetic stimulation of arterioles > vasodilation > decreased blood pressure

Question 11

Baroreceptors protect circulation against _ changes in BP.

Answer 11

short-term

Question 12

chemoreceptors

Answer 12

special cells in the aorta and carotid arteries that are sensitive to blood levels of oxygen, carbon dioxide and pH.

Question 13

hypoxia, hypercapria, and acidosis have what effect on chemoreceptors?

Answer 13

low blood oxygen, high blood carbon dioxide, or low pH > stimulate chemoreceptors to send impulses to vasomotor center

increased sympathetic stimulation of arterioles > vasoconstriction > causes blood pressure to rise

(increase speed of return of blood to heart and lungs)

Question 14

What affect do the higher brain centers have on vasomotor activity?

Answer 14

anxious/angry/very emotional > cerebral cortex and hypothalamus stimulate vasomotor center

increase sympathetic impulses to arteriorles > vasoconstriction > increased blood pressure

Question 15

What chemicals have an effect on blood pressure?

Answer 15

epinephrine and norepinephrine; antidiuretic hormone; histamine; nicotine

all short-term control

Question 16

epinephrine and norepinephrine

Answer 16

hormones produced by the adrenal gland during periods of stress

Question 17

Epinephrine/NE cause cardiac output to _, resulting in _ and blood pressure to _

Answer 17

increase; vasoconstriction of all vessels (except skeletal and cardiac muscle); increase

Question 18

antidiuretic hormone

Answer 18

a hormone made by the hypothalamus that stimulates the kidneys to conserve water

Question 19

Antidiuretic hormone causes __, causing blood pressure to __.

Answer 19

vasoconstriction (for severe blood loss); increase

Question 20

histamine

Answer 20

potent vasodilator produced during the inflammatory response and certain allertiges - causes blood pressure to decrease (as in anaphylactic shock)

Question 21

nicotine

Answer 21

causes intense vasoconstriction - blood pressure goes up

Question 22

Which chemicals cause vasodilation, and therefore blood pressure to go down?

Answer 22

histamine

Question 23

Which chemicals cause vasoconstiction, and therefore blood pressure to go up?

Answer 23

epinephrine/norepinephrine, antidiuretic hormone, nicotine

Question 24

renal regulation of blood pressure

Answer 24

long-term control; the kidneys act directly and indirectly to provide major long term control of blood pressure by altering blood volume

Question 25

direct renal regulation of blood pressure

Answer 25

pressure diuresis: blood pressure increases > rate of fluid filters through kidneys increases > urine production increases

blood volume decreases > blood pressure decreases

Question 26

indirect renal regulation of blood pressure

Answer 26

renin-angiotensin mechanism

Question 27

What are the four classic vital signs?

Answer 27

blood pressure, pulse/heart rate, temperature, respitory rate

(newer: O2 saturation)

Question 28

Where is blood pressure usually measured?

Answer 28

left brachial artery (closed to the aorta) using a sphygomomanometer

Question 29

How is blood pressure reported? [x / y]

Answer 29

Systolic Blood Pressure / Diastolic Blood Pressure

Question 30

When is systolic blood pressure reported?

Answer 30

at the first Korotkoff sound - produced when blood is able to squirt through during ventricular systole (eg. heart contracting)

Question 31

When is diastolic blood pressure reported?

Answer 31

when the Korotkoff sound disappears - when the vessel is wide open and blood is able to flow through smoothly (eg. heart is between contractions)

Question 32

What are the steps of measuring blood pressure?

Answer 32

1. BP cuff wrapped around arm over brachial artery just superior to the elbow
2. cuff inflated until P in cuff > P in artery - wall compresses and no blood flows through, no pulse felt, no sound heard in stethoscope
3. cuff gradually deflated - SBP reported at first Korotkoff sound when blood is able to squirt through during ventricular systole
4. Korotkoff sound gets louder and then disappears entirely when the vessel is wide open, allowing blood to flow smoothly - DBP reported

Question 33

systolic BP

Answer 33

force with which blood is pusing against arterial walls when the heart is contracting (in systole)

Question 34

diastolic BP

Answer 34

force with which blood is pushing against arterial walls when the heart is relaxing (in diastole)

Question 35

Normal blood pressure varies with what?

Answer 35

age, gender, weight, mood, race, posture, and physical activity

Question 36

pulse pressure

Answer 36

the difference between systolic and diastolic blood pressure, felt as throbbing in the artery. It decreases as you move farther away from the heart, disappears in arterioles

Question 37

MAP

Answer 37

mean arterial pressure

MAP = DBP + (PP/3) = DBP + ((SBP-DBP)/3)