The cardiac cycle - phases. Differences between the left and the right part of the heart.

Question 1

phase 1

Answer 1

ATRIAL SYSTOLE/ CONTACTION

VALVES
- AV valves open
- SL valves closed

SA node fires an AP causing atria to contract which pushes blood from atria into ventricles to complete ventricular filling

Question 2

phase 2

Answer 2

ISOVOLUMETRIC CONTRACTION

AV valves closed + SL valves closed

ventricular contract (depolarise)
but are unable to eject blood yet due to lack of power
so volume remains same

Question 3

phase 3

Answer 3

VENTRICULAR EJECTION

AV valve closed + SL valve open

ventricles have enough pressure to force open SL valves
blood from ventricles -> aorta
ventricle volume decreases

Question 4

phase 4

Answer 4

ISOVOLUMETRIC RELAXATION

AV valve closed as ventricle pressure > atria pressure

+ SL valve closed as ventricle pressure > artery pressure

ventricle volume is constant

Question 5

phase 5

Answer 5

VENTRICULAR FILLING

AV valves open + SL valves closed

atria pressure > ventricle pressure
- passive bloodflow from atria to ventricles

• rapid + slow filling = diastasis

Question 6

differences between the left and the right part of the heart - 1a

Answer 6

PATHWAY - PULMONARY

deooxygenated blood from body -> lungs to become oxygenated

1 - right atrium
2 - right ventricle
3 - pulmonary artery
4 - lungs
5 - pulmonary veins
6 - left atrium

Question 7

differences between the left and the right part of the heart - 1b

Answer 7

LEFT SIDE = SYSTEMIC CIRCULATION

1 - left atrium
2 - left ventricle
3 - aorta
4 - arteries
5 - arterioles
6 - capillaries
7 - venules
8 - veins
9 - vena cava
10 - right atrium

Question 8

differences between the left and the right part of the heart - 2

Answer 8

VALVES

RHS
- tricuspid valves between right atrium + right ventricle
- pulmonic valve between right ventricle to pulmonic artery

LHS
- bicuspid valve between left atrium + left ventricle
- aortic valve between left ventricle + aorta

Question 9

differences between the left and the right part of the heart - 3

Answer 9

PRESSURE

RHS = low pressure
- bloodflow only to lungs = pulmonic
- thinner walls = less resistance

LHS = high pressure
- bloodflow to whole body = systemic
- thicker walls = more resistance

Question 10

differences between the left and the right part of the heart - 4

Answer 10

oxygen demand

RHS = lower due to lower pressure

LHS = higher due to higher pressure

Question 11

differences between the left and the right part of the heart - 5

Answer 11

function

RHS = deoxygenated blood into lungs

LHS = oxygenated blood into tissues