2. Cardiac Cycle

Question 1

What is the definition of convection?

Answer 1

Mass movement of fluid caused by pressure difference

Question 2

What are the components of convection in the human body?

Answer 2

• Heart – driving force (creates large pressures)
• Arteries – distribution (alter blood flow)
• Capillaries – exchange (huge numbers - thin)
• Veins – reservoir (2/3rd of blood volume)

Question 3

1st stage of electrical conduction through the heart?

Answer 3

Electrical activity generated in the SA nodes spreads out via gap junctions in the atria

Question 4

2nd stage of electrical conduction through the heart?

Answer 4

At AV node, conduction is delayed to allow correct filling of ventricles

Question 5

3rd stage of electrical conduction through the heart?

Answer 5

Conduction occurs rapidly through bundle of His into ventricles

Question 6

4th stage of electrical conduction through the heart?

Answer 6

Conduction through Purkinje fibres spreads quickly throughout the ventricles

Question 7

What does the P wave represent?

Answer 7

Atrial depolarisation

Question 8

What does the PR segment represent?

Answer 8

AV nodal delay

Question 9

What does the QRS complex represent?

Answer 9

Ventricular depolarisation (atria repolarising simultaneously).

Question 10

What does the ST segment represent?

Answer 10

Time during which the ventricles are contracting and emptying

Question 11

What does the T wave represent?

Answer 11

Ventricular repolarisation

Question 12

What does the TP interval represent?

Answer 12

Time during which ventricles are relaxing and filling