Arteries: oxygenated blood away from the heart. Veins: deoxygenated blood to the heart
1 of 28
What does the pulmonary artery carry and where to?
Deoxygenated blood from the heart to the lungs
2 of 28
What does the pulmonary vein carry and where to?
Oxygenated blood from the lungs to the heart
3 of 28
Where are semilunar valves present?
In the aorta and the pulmonary artery
4 of 28
What do the atrioventricular valves do?
They prevent backflow of blood when the pressure increases
5 of 28
Which chamber of the heart has a thick muscular wall and why?
The left ventricle- it has to pump all the blood around the body at a high pressure
6 of 28
What is meant by systole?
When the heart contracts/empties
7 of 28
What is meant by diastole?
When the heart relaxes/fills
8 of 28
What is the cardiac output?
The volume of blood pumped per minute
9 of 28
How is the cardiac output calculated?
Stroke volume (cm3) x Heart rate (bpm)
10 of 28
Name 3 features of the cardiac muscle
1) myogenic- no need for external stimulation 2) Has its own separate blood supply 3) Cells react to give maximum contraction
11 of 28
What is step 1 of the cardiac cycle?
ATRIAL SYSTOLE- the atria contract, the blood flows from atrium to ventricle, the valves in the veins close. Pressure increases and volume decreases
12 of 28
What is step 2 of the cardiac cycle?
VENTRICULAR SYSTOLE. Ventricles contract, atrioventricular valves are pushes shut by pressurised blood in ventricles. Semilunar valves open. Blood flows from ventricles to arteries. Pressure increases, volume decreases
13 of 28
What is step 3 of the cardiac cycle?
VENTRICULAR DIASTOLE. Atria and ventricles relax, semilunar valves are shoot. Blood flows from the veins -> artria -> ventricles. Pressure decreases, volume increases
14 of 28
Talk about the cardiac cycle in terms of pressure and volume changes
As ventricle muscle contracts, pressure increases and blood is forced out. As pressure in one chamber exceeds another, valves will open or shut.
15 of 28
How is the heartbeat controlled? (1-4)
SAN sets rhythm- sends out regular waves of electrical activity to atrial walls. 2) Atria contract 3) Waves are transferred after a delay (so ventricles contract after atria have emptied) to the AVN. 4) AVN passes waves to Bundle of His.
16 of 28
How is the heartbeat controlled (5-7)
5) Bundle of His conducts waves to the Purkinje fibres in ventricular walls. 6) Purkinje fibres carry waves up into muscular walls of ventricles, causing them to contract simultaneously from the bottom up.
17 of 28
What is the heart rate?
Number of contractions of the heart per minute
18 of 28
What type of condition is coronary heart disease?
Multi-factoral
19 of 28
What happens if coronary circulation is interrupted (e.g by a blocked artery)?
1) part of heart wall is deprived of oxygen and glucose 2) cells in this region cannot respire and release energy 3) muscles in this region will be unable to contract
20 of 28
What is an atheroma?
A mixture of fatty substances including cholesterol, cells and fibres of connective tissue
21 of 28
What is atherosclerosis?
The process in which an atheroma is deposited in the walls of the arteries. It narrows an artery and roughens its endothelium.
22 of 28
What could result from atherosclerosis?
A blood clot (because roughened surface triggers clot formation) or a blocked artery (by a blood clot because its narrowed already by the atheroma)
23 of 28
What is an aneurysm?
When a weakened wall of an artery becomes distended
24 of 28
How would an aneurysm develop?
The atheroma weakens the artery wall of the pressure of the blood distends the artery
25 of 28
What will happen if an aneurysm bursts?
Blood will be lost- in the brain it can cause a stroke from too much pressure on the brain.
26 of 28
What are the risk factors of CHD?
Smoking, not enough exercise, tiredness, alcohol, obesity, poor diet (one high in saturated fat), high blood pressure, high cholesterol
27 of 28
How can diet increase the risk of CHD?
Too much saturated fat or cholesterol can form an atheroma in the artery walls. This blocks coronary arteries, so less oxygen can reach the heart muscle. This increases blood pressure and an increased risk of a clot or aneurysm.
28 of 28
Other cards in this set
Card 2
Front
What does the pulmonary artery carry and where to?
Comments
No comments have yet been made