CH12 the heart Flashcards
1
Q
What side of the heart does oxygenated blood flow
A
Left
2
Q
What side of the heart does deoxygenated blood flow
A
Right
3
Q
Why doesn’t heart muscle get fatigued
A
- coronary arteries supply muscle with oxygenated blood
4
Q
What does inelastic pericardial membrane do
A
- prevents heart over-distending with blood
5
Q
What is the order of blood flow in left side of heart
A
- enters left atrium from pulmonary vein
- pressure builds and bicuspid valve opens between left atrium and ventricle
- ventricle fills with blood and when both chambers full, atrium contracts
- blood forced into left ventricle which contracts
- blood forced through semi lunar valves into aorta
6
Q
What is order of blood flow in right side of heart
A
- blood enters right atrium through superior and inferior vena cava at low pressure
- blood fills and pressure builds until tricuspid valve opens and ventricle fills
- when both chambers fill, atrium contracts and blood forced into ventricle
- ventricle contracts and blood forced through semi lunar valves into pulmonary artery
7
Q
Why is muscular wall thicker on left side
A
- has to produce sufficient force to overcome resistance of aorta and arterial systems of whole body
- has to move blood to all extremities of body
- right side has to pump blood short distance and only has to overcome resistance of pulmonary circulation
8
Q
How long does a heart beat last
A
- 0.8 seconds
9
Q
Diastole
A
- heart relaxes
- atria and ventricles fill with blood
- volume and pressure of blood builds but pressure in arteries is at minimum
10
Q
systole
A
- atria contract (atrial) followed by ventricles (ventricular)
- pressure inside increases dramatically and blood forced out
- volume and pressure are low at end of systole
11
Q
What makes ‘lub’ sound
A
- blood forced against atrio-ventricular valves as ventricles contract
12
Q
What makes ‘dub’ sound
A
- backflow of blood closes semi lunar valves into aorta and pulmonary artery as ventricles relax
