10) Pulse: Physiology And Regulation

Question 1

What is the pulse?

Answer 1

• The bounding or pulsation of arterial blood flow
• Palpable at various points on the body
• Indicates status of the circulatory system

Question 2

How should the pulse be assessed?

Answer 2

• Palpate to assess contour, amplitude, and strength of each beat
• Compare characteristics on right and left sides
• Palpate carotid pulses separately to avoid compromising brain blood flow

Question 3

What should be noted when palpating pulses?

Answer 3

• Pressure or volume of pulse wave (normal, bounding, thready, absent)
• Rigidity or hardness of the vessel wall
• Presence of any palpable vibration (thrill)

Question 4

What indicates vascular dysfunction?

Answer 4

• Diminished or absent pulse distal to an injury site

Question 5

What are normal pulse findings in older adults?

Answer 5

• Either dorsalis pedis or posterior tibial pulse may be difficult to locate, but not both on same foot

Question 6

What creates the palpable pulse?

Answer 6

• Intermittent ejection of blood from the heart into the aorta
• Expansion and recoil of the arterial wall with each blood injection

Question 7

What information does pulse palpation provide?

Answer 7

• Pulse rate
• Rhythm
• Strength
• Equality between sides

Question 8

What regulates the pulse rate (heart rate)?

Answer 8

• Sympathetic nervous system (increases rate via epinephrine/norepinephrine)
• Parasympathetic nervous system (decreases rate via acetylcholine)

Question 9

What initiates cardiac contraction?

Answer 9

• Electrical impulses originating from the sinoatrial node

Question 10

What is the stroke volume?

Answer 10

• Approximately 60-70 mL of blood entering the aorta with each ventricular contraction

Question 11

How is the pulse wave created?

Answer 11

• Aortic wall distends with stroke volume ejection
• Pulse wave travels to distal arteries

Question 12

How is the pulse rate measured?

Answer 12

• By palpating a peripheral artery against bone/muscle
• Counting pulsing sensations in 1 minute

Question 13

What is cardiac output?

Answer 13

• The volume of blood pumped by the heart in 1 minute
• The product of heart rate and stroke volume

Question 14

What is a typical adult cardiac output?

Answer 14

• About 5000 mL/minute
• E.g. 70 beats/min x 70 mL stroke volume = 4900 mL/min

Question 15

Does a change in heart rate or stroke volume always change cardiac output?

Answer 15

• No, cardiac output or blood in arteries may not change

Question 16

What factors regulate stroke volume?

Answer 16

• Mechanical factors
• Neural factors
• Chemical factors

Question 17

How does heart rate affect blood pressure?

Answer 17

• Increasing rate decreases filling time, lowering BP
• Decreasing rate increases filling time, raising BP

Question 18

What indicates a health problem?

Answer 18

• Inability of BP to respond to heart rate changes

Question 19

How does an abnormal pulse affect cardiac output?

Answer 19

• Slow, rapid, or irregular pulse alters cardiac output

Question 20

How is cardiac output assessed?

Answer 20

• Palpate peripheral pulses
• Listen to apical heart sounds