ILA 3 chest pain

Question 1

What is cardiac output and what is the equation for it?

Answer 1

Volume of blood heart pumps in one minute
CO= stroke volume x heart rate

Question 2

What is the average CO?

Answer 2

5L/min

Question 3

What 4 factors affect heart rate?

Answer 3

Autonomic innervation
Hormones
Fitness levels
age

Question 4

What 7 factors affect stroke volume?

Answer 4

Contractility
Preload
Afterload
Heart size
fitness
gender
contraction duration

Question 5

What is preload and afterload respectively?

Answer 5

End diastolic volume
Pressure the heart must work against during systole

Question 6

What are 5 factors that affect blood pressure?

Answer 6

Blood viscosity
Volume of Blood
Elasticity of Blood vessels
Peripheral Vascular resistance
Cardiac output

Question 7

Why does heart failure cause oedema in legs/ankles?

Answer 7

Less blood being pumped out means an increase in BP before the heart causing fluid to move into surrounding tissues hence causing pitting oedema

Question 8

What does the frank-starling law state?

Answer 8

Greater the stretch on myocardium before systole, the stronger the ventricular contraction

Question 9

Why does increased EDV cause an increased ventricular contraction?

Answer 9

Actin and myosin filaments brought to more optima degree of overlap for force generation

Question 10

What are the two types of heart failure by Frank-Starling mechanism?

Answer 10

Systolic and diastolic dysfunction

Question 11

What does Diastolic heart failure result in?

Answer 11

Lower EDV and reduced stroke volume so lower BP

Question 12

What does the P wave represent on an ECG?

Answer 12

Atria depolarisation (Diastole)

Question 13

What does the QRS represent on an ECG?

Answer 13

Ventricular depolarisation

Question 14

What makes the first heart sound?

Answer 14

AV valve shutting
Ventricular pressure>Atrial pressure

Question 15

What causes the second heart sound?

Answer 15

Mitral valve shutting

Question 16

When does most myocardial perfusion occur? Why?

Answer 16

During Diastole
Heart closes coronary arteries during systole causing blood to flow back into the aorta

Question 17

Where does deoxygenated blood drain from the coronary arteries?

Answer 17

Coronary sinus then right atrium

Question 18

What artery first branches off the left coronary artery? What does it supply?

Answer 18

Left anterior descending artery
Both ventricles

Question 19

What other artery branches off the Left coronary artery? Where does it run? What does it supply?

Answer 19

Circumflex artery
Goes to the inferior/diaphragmatic surface and supplies left atrium and parts of the right and left ventricle

Question 20

What artery arises from the circumflex artery?
What does it supply?

Answer 20

Left marginal artery
Left ventricle

Question 21

What does the Right ventricle supply blood to? (4)

Answer 21

Right ventricle
Right atrium
SA and AV node

Question 22

What is the branch and what is a continuation of the RCA? What does each supply? Where does the continuation run?

Answer 22

Right marginal artery (Supplies inferior border)
Posterior interventricular artery (Runs in posterior interventricular sulcus and supplies both ventricles)

Question 23

What is the effect of occlusion of the LAD artery?

Answer 23

Blocks impulse conduction between atria and ventricles

Question 24

Signs on ECG of occluded LAD?

Answer 24

ST elevation and prolonged PR

Question 25

What are the effects of occlusion of RCA?

Answer 25

Conduction of nodes affected causing contractions to become out of rhythm or slower

Question 26

What does Mitral valve stenosis cause an increase in?

Answer 26

Higher left atrial end systolic volume

Question 27

What is the average EDV and stroke volume in a healthy person?

Answer 27

120mls (EDV)
70mls (Stroke volume)

Question 28

What phase are both the atria and ventricles in during the isovolumetric ventricular relaxation phase of the cardiac cycle?

Answer 28

Both in diastole