Chapter 5 Heart & monitoring heart function

Question 1

What is the need for a mass transport system in multicellular organisms?

Answer 1

Due to higher demand for nutrients and greater production of waste from a higher metabolic rate and activity level.

Question 2

What is the general structure of the heart?

Answer 2

The heart acts as 2 pumps separated by a septum.

Question 3

What is the function of the left side of the heart?

Answer 3

Pumps oxygenated blood to the rest of the body.

Question 4

What is the function of the right side of the heart?

Answer 4

Pumps deoxygenated blood to the lungs.

Question 5

What type of muscle is cardiac muscle?

Answer 5

Specialised striated muscle that does not require nerve stimulation to contract (myogenic).

Question 6

What is the contraction speed of cardiac muscle compared to skeletal and smooth muscle?

Answer 6

Intermediate.

Question 7

What do the carotid arteries do?

Answer 7

Carry oxygen-rich blood to the head, brain, and face.

Question 8

What is the role of the aorta?

Answer 8

Carries oxygenated blood from the left ventricle to the body at high pressure.

Question 9

What does the pulmonary artery do?

Answer 9

Carries deoxygenated blood from the right ventricle to the lungs.

Question 10

What is the function of the pulmonary vein?

Answer 10

Carries oxygenated blood from the lungs to the left atrium.

Question 11

What is the role of the atria in the heart?

Answer 11

Contract to generate a force to move blood at low pressure into the ventricles.

Question 12

What differentiates the left ventricle from the right ventricle?

Answer 12

The left ventricle has the thickest wall and pumps oxygenated blood into the aorta at high pressure.

Question 13

What prevents backflow of blood from the aorta to the left ventricle?

Answer 13

Aortic valve.

Question 14

What prevents backflow of blood from the pulmonary artery to the right ventricle?

Answer 14

Pulmonary valve.

Question 15

What separates the right and left sides of the heart?

Answer 15

Septum.

Question 16

What is the function of the vena cava?

Answer 16

Carries deoxygenated blood from the body to the right atrium.

Question 17

What do chordae tendinae do?

Answer 17

Hold valves in place and prevent them from inverting during pressure changes.

Question 18

What is the cardiac cycle?

Answer 18

The events in a single heartbeat, approximately 0.8 seconds long in humans.

Question 19

What happens during diastole?

Answer 19

The heart relaxes and fills with blood.

Question 20

What occurs during ventricular systole?

Answer 20

Ventricles contract and eject blood into the pulmonary artery and aorta.

Question 21

What are the heart sounds ‘lub’ and ‘dub’ associated with?

Answer 21

‘Lub’ = atrioventricular valves closing; ‘Dub’ = semilunar valves closing.

Question 22

What initiates the wave of electrical excitation in the heart?

Answer 22

Sino-atrial node (SAN).

Question 23

What is the role of the atrio-ventricular node (AVN)?

Answer 23

Delays electrical activity to ensure atria have stopped contracting before ventricles contract.

Question 24

What is stroke volume?

Answer 24

Volume of blood pumped out of the left ventricle during each cardiac cycle (approximately 60-80 cm³).

Question 25

What is the formula for cardiac output?

Answer 25

CO = SV x HR.

Question 26

What factors affect heart rate?

Answer 26

* Age * Genetics * Diseases * Physical activity level * Smoking * Diet

Question 27

What is the significance of the SAN being myogenic?

Answer 27

It does not require input from the brain to initiate the heartbeat.

Question 28

What happens if both ventricles contract simultaneously?

Answer 28

It would cause backflow of blood into the atria, decreasing the volume of blood moved through the heart.

Question 29

What is the purpose of measuring pulse rate?

Answer 29

To assess heart rate and cardiovascular health.

Question 30

How can standard deviation (SD) be used in data processing?

Answer 30

To assess the reliability of the data.

Question 31

What does a smaller standard deviation indicate?

Answer 31

More reliable data set.

Question 32

What does it mean to reject the null hypothesis in a t-test?

Answer 32

There is a significant difference between the mean values of two groups.

Question 33

What is the formula to determine degrees of freedom for a paired t-test?

Answer 33

Paired t-test DoF = number of pairs of data - 1

Question 34

What is the formula to determine degrees of freedom for an unpaired t-test?

Answer 34

Unpaired t-test DoF = (n1 + n2) - 2

Question 35

At the 95% confidence level, what decision is made if tcalculated > tcritical?

Answer 35

Reject the null hypothesis

Question 36

At the 95% confidence level, what decision is made if tcalculated < tcritical?

Answer 36

Accept the null hypothesis

Question 37

What do ECGs measure?

Answer 37

Spread of electrical excitation through the heart

Question 38

What is the process called that measures electrical activity of the heart?

Answer 38

Electrocardiography

Question 39

Does an ECG directly measure electrical activity of the heart?

Answer 39

No, it measures small electrical differences in skin due to heart activity

Question 40

What can changes in peaks of an ECG be used to detect?

Answer 40

Heart conditions

Question 41

Are there any risks associated with ECG procedures?

Answer 41

Generally, there are no risks

Question 42

What might some patients experience during an exercise electrocardiogram?

Answer 42

Arrhythmias or heart distress

Question 43

What is ventricular fibrillation (VF)?

Answer 43

No regular pattern to ECG; muscle in ventricle walls flutter

Question 44

What is the most common cause of ventricular fibrillation?

Answer 44

Myocardial infarction

Question 45

What is the effect of ventricular fibrillation on a victim?

Answer 45

No blood circulation; usually unconscious; almost certainly fatal

Question 46

What is the immediate treatment for ventricular fibrillation?

Answer 46

Use of a defibrillator

Question 47

What characterizes atrial fibrillation (AF) on an ECG?

Answer 47

Muscle walls of atria contract arrhythmically, no distinct P waves

Question 48

What is the most common cause of atrial fibrillation?

Answer 48

Abnormalities or damage to the heart's structure

Question 49

What are some effects of atrial fibrillation?

Answer 49

* Increased risk of stroke * Increased risk of heart failure * Chronic fatigue

Question 50

What defines bradycardia in terms of resting heart rate?

Answer 50

Resting HR between 40-60 bpm

Question 51

What are the ECG features of bradycardia?

Answer 51

Longer gaps between QRS complexes; ECG looks normal except delay

Question 52

What is the treatment for severe bradycardia?

Answer 52

Artificial pacemaker

Question 53

What defines tachycardia in terms of resting heart rate?

Answer 53

Resting HR above 100 bpm

Question 54

What are the ECG features of tachycardia?

Answer 54

Shorter gaps between QRS complexes

Question 55

What is the most common cause of myocardial infarction?

Answer 55

Occlusion of coronary artery following rupture of atherosclerotic plaque

Question 56

What are some symptoms of a heart attack?

Answer 56

* Chest pain * Pain in other parts of the body * Shortness of breath

Question 57

What should you do first if you suspect someone is having a heart attack?

Answer 57

Call 999

Question 58

What is the CPR compression rate for adults?

Answer 58

100-120 compressions a minute

Question 59

What is the purpose of an automated external defibrillator (AED)?

Answer 59

Helps to establish a regular heartbeat during a cardiac arrest

Question 60

What do you do if an AED indicates the heart is fibrillating?

Answer 60

AED applies electrical discharge to stop fibrillation