(DONE) Week 9 Lab Manual 18

Question 1

define: stroke volume
define: cardiac output

Answer 1

• the amount of blood pumped out of the right ventricle to the lungs and the amount pumped from the left ventricle to the rest of the body
• rate at which heart pumps blood per min; symbol Q.

Question 2

Explain the function of stroke volume

Answer 2

The stroke volume of blood is active in absorbing oxygen from the lungs while unloading carbon dioxide to the air and carrying absorbed oxygen and food around the body

Question 3

What is the effectiveness of the cardiovascular system dependent on (2)? What is blood pressure dependent on(2)?

Answer 3

• dimensions and cardiac output

- cardiac output and flexibility of blood vessels

Question 4

Give the equations for cardiac output

Answer 4

• Q= SV x HR

- Q/flow= mean arterial blood pressure divided by total peripheral resistance (TPR)

Question 5

Give the following average measurements for a male at rest

• Stroke volume SV
• Heart rate HR
• Cardiac output Q

Answer 5

• SV: 80mL
• HR: 70beats/ min
• Q: 5.60/ min

Question 6

Define: Sinoatrial node (pacemaker) (SA node) and give its location

Answer 6

• contracts heart by sending electrical signals that cause it to contract
• located in the right atrium

Question 7

electrocardiograph (ECG)

Answer 7

• equipment that allows us to see the electrical activity of the heart

Question 8

Define: Einthoven leads

Answer 8

• the 3 standard electrode positions used to produce an electrocardiogram and allows for 12 different ECG patterns to be observed

Question 9

• give the Einthoven leads (3 main, 2 supporting leads)

Answer 9

• left wrist
• right wrist
• left ankle
• right ankle (reference electrode)
• chest (exploring electrode; optional)

Question 10

How is a subject prepped before an ECG reading

Answer 10

• area where skin will contact the electrodes is cleaned and scrubbed with an abrasive to remove dead surface cells
• a conducting gel is applied
• electrodes are held in place by being incorporated into an adhesive patch

Question 11

What is the importance of an ECG

Answer 11

• analysis of an ECG can reveal heart disfunctions

- example: delayed contractions of the heart chambers caused by disease creates an abnormal shaped waveform

Question 12

define: bipolar ECG

Answer 12

• 3 electrode system is used: 2 recording and 1 reference electrode
• 2 placed on subjects chest and remote electrode on the scapula or sternum

Question 13

Why is a 3 electrode system better than a 12 electrode system for muscular activity testing?

Answer 13

• subject cannot be tested properly because motion is restricted by so many electrodes
• requires little beforehand prep

Question 14

Exercise electrocardiography is used to determine what (2)?

Answer 14

• if oxygen demand is greater than oxygen supply due to obstructed flow (given by ST segment depression)
• a more accurate measure of heart rate during exercise (in comparison to stethoscope, or palpation of neck or wrist)

Question 15

define a sphygmomanometer

Answer 15

• equipment used to measure blood pressure

includes:
- compression bag enclosed in a cuff
- inflating bulb
- pump (increases pressure)
- manometer (reads applied pressure)
- controlled exhaust (deflates system)
- stethoscope

Question 16

define: systolic pressure (SBP)

Answer 16

• pressure during contractions

Question 17

define: diastolic pressure (DBP)

Answer 17

• pressure between heart contractions

Question 18

pulse pressure equation

Answer 18

pulse pressure= (SBP) - (DBP)

- unit: mmHg

Question 19

mean arterial pressure equation

Answer 19

MAP= [(SBP-DBP)/3] +DBP

- UNIT: mmHg

Question 20

How is a blood pressure reading expressed?

Answer 20

• systolic pressure/ diastolic pressure

Question 21

Describe the difference between measuring blood pressure indirectly and directly (give the method)

Answer 21

• indirect: sphygmomanometer

- direct: catheter into artery

Question 22

Describe the importance of the bag and cuff size of the sphygmomanometer; give the width of a bag used for the average adult

Answer 22

• if its too narrow, BP reading will be very high
• too wide, BP reading will be very low
• inflatable bag should be 20% wider than diameter of the limb being measured
• 25cm-35cm circumference of bag for the average adult

Question 23

Describe the 3 different types of manometers

Answer 23

• mercury gravity manometer: more accurate than the aneroid BUT mercury spills are toxic
• aneroid manometer: metal bellows elongate with the application of pressure
• electronic blood pressure monitor

Question 24

What are some factors that can impact blood pressure readings? How do we try and negate that in the lab?

Answer 24

• anxiety, emotional turmoil, meals, tabacco, bladder distension, climate variation, exertion, and pain (stimulus of any in general)
• subject should be comfortably seated in a chair with back support and in a quiet room, resting for at least 5 min with legs uncrossed and feet on floor. forearm should be supported at heart level on a smooth surface

Question 25

describe the Astrand test

Answer 25

• predicts maximum aerobic power (VO2 max) from heart rate measured at the end of a six minute work rate on a bicycle ergometer.

Question 26

What is the standard error of prediction of VO2 max

Answer 26

• 15% in moderately trained individuals of different ages but 10% in well trained individuals of the same age

Question 27

List the equipment used in the Astrand test (6)

Answer 27

• monarch bicycle ergometer
• electrocardiograph/ heart rate monitor
• pre gelled disposable electrodes
• stopwatch for recording exercise duration
• sphygmomanometer
• ruler

Question 28

What are the work rates for cycle ergometry commonly expressed in?

Answer 28

• kilopond-meters per minute

- kilopond: force of gravity acting on a 1 kg mass

Question 29

What is the pedalling frequency used in the Astrand test

Answer 29

50rpm