Lesson 2 Cardiovascular System

Question 1

What is the cardiac cycle

Answer 1

The cardiac cycle is the mechanic event of ONE heart beat.

Question 2

Diastole

Answer 2

1. The heart at this point is relaxing and filling up with blood.
2. The atria fill with blood and pressure builds within these chambers.
3. As the pressure increases, the valves begin to slowly open and let small amounts of blood through.

Question 3

Systole

Answer 3

Pressure has built up in the atria during diastole phase.
ATRIAL SYSTOLE PHASE
1. Valves are now forced open, both atrial contract and remaining blood is forced into ventricles.
VENTRICULAR SYSTOLE PHASE
1. Blood is now in ventricles, ventricles now contract increasing the pressure within these chambers.
2. Aortic valve and Pulmonary valve are
forced open, allowing blood to be pushed through into the aorta or the pulmonary artery

Question 4

Conduction system of the heart

Answer 4

The heart is MYOGENIC – produces its own impulse!
Impulse starts in the SINOATRIAL NODE (SA NODE)
Then the pulse travels down into the ATROVENTRICULAR NODE (AV NODE) and onto the BUNDLE OF HIS.
These impulses here stimulate the atria
From here, the pulse travels down the left and right branches and down into the PURKINJE FIBRES.
Here the ventricles are squeezed.

Question 5

What are the names of the valves in the heart and where are they located?

Answer 5

Tricuspid – between RA and RV
Bicuspid valve between LA and LV
Semi lunar valves – in the pulmonary artery (stops backflow into the RV) and the aorta (stops back flow into the LV)

Question 6

Starting at the venae cavae (inferior and superior vena cava), place the following structures in the correct order that a red blood cell would pass on its journey through the heart

Answer 6

Venae cavae – RA – Tricuspid valve – RV – semilunar valve – pulmonary artery – lungs – pulmonary vein – LA – bicuspid valve – LV – semilunar valve - aorta - body