Cardiac Cycle

Question 1

Define convection

Answer 1

Mass movement of fluid caused by pressure difference

Question 2

Pulmonary artery vs pulmonary vein

Answer 2

P-artery transports deoxygenated blood from the right ventricle to the lungs

P-vein transports oxygenated blood from the lungs to the heart

Question 3

Sinoatrial node

Answer 3

• located in right atrium
• produces action potentials
• electrial condunction throughout heart
• pacemaker which sets rhythm of the heart

Question 4

What is the function of the atrioventricular node

Answer 4

• connects right atrium to right ventricle
• delays impulses
• atria have time to eject their blood into ventricles before ventricles contract

Question 5

Phase 4

Answer 5

• After hyperpolarization, membrane potential returns to the resting membrane potential.
• It repolarises
• At minus 50mV, Na+ channel activated, slow Na+ influx and slow depolarisation

Question 6

Phase 0

Answer 6

• Rapid depolarisation
• Voltage gated Ca2+ channel opens
• Ca2+ influx

Question 7

Phase 3

Answer 7

• Cell becomes negative again, repolarisation
• Ca2+ channels close
• Voltage gated K+ channel open, K+ leave

Question 8

Phase 1

Answer 8

-early repolarisation, cells begins to become negative after rapid depolarisation

Question 9

Phase 2

Answer 9

• Plateau phase is where repolarisation briefly stops
• line plateaus/is horizontal
• due to voltage gated Ca2+ open which outweigh repolarisation

Question 10

Electrical conduction through heart

Answer 10

-SA node generates, atria contract, AV node, electrical impulse delayed, bundle of His into ventricles, purkinje fibres spread conduction throughout ventricles, ventricles contract begins at apex

Question 11

Lung circulation

Answer 11

1) atrial contraction, ventricular filling
2) right atrium pressure > right ventricle pressure
3) tricuspid valve forced open
4) isovolumetric contraction
5) right ventricle pressure > pulmonary artery
6) pulmonary valve forced open
7) ejection into pulmonary artery
8) isovolumetric relaxation
9) pulmonary artery transports deoxygenated blood to lungs

Question 12

Systemic circulation

Answer 12

Same principle as lung circulation but with left atrium, mitral valve, left ventricle, aortic valve, aorta transports oxygenated blood to body

Question 13

What is ESV

Answer 13

End systolic volume

• volume of blood in ventricles at the end of contraction, systole
• 40ml

Question 14

Draw the “left ventricular volume changes” graph

Answer 14

Show isovolumetric contraction and relaxation

Question 15

Draw “ventricular pressure-volume loop” graph

Answer 15

Show where valves open and close

Question 16

What is JVP

Answer 16

Jugular venous pressure
Connected to right atrium without valves
Represents atrium changes
Clinical measurement

Question 17

S1

Answer 17

Lub sound

Tricuspid or mitral valves close before v systole begins