heart Flashcards
Describe the passage of blood through the right side of the heart.
(superior and inferior) Vena Cava
Right atrium
Right AV valve (tricuspid)
Right ventricle
Semi lunar valve
Pulmonary Artery
Describe the passage of blood through the left side of the heart.
Pulmonary vein
Left atrium
Left AV valve (bicuspid)
Left ventricle
Semi lunar valve
Aorta
How does the thickness of the left ventricle walls compare to the right ventricle walls?
Thicker, more muscular walls.
What is the importance of the muscle tissue in the artery walls?
Contracts
Arteries constrict to regulate blood flow.
Why are the walls of the left ventricle thicker and more muscular?
Contracts more powerfully
Blood pumped out at a higher pressure
Pumps blood all around the body
Why do the ventricles have thicker walls than the atria?
So they can push blood out of the heart
Atria just needs to push blood the short distance into ventricles
What is the purpose of the function attaching the AV valves to the ventricles?
Stops AV valves being forced up into atria when ventricles contract.
When will a valve open?
When the pressure BEHIND the valve is greater than the pressure in front of the valve
What is the importance of valves only opening when the pressure is high behind them than in front?
Blood flows in ONE DIRECTION
Unidirectional
What is the importance of the elastic tissue in the artery walls?
Stretch at high pressure when left ventricle contracts
Recoil at low pressure when left ventricle relaxes
Smooth blood flow
What are the stages of the cardiac cycle?
- Ventricles relax and atria contract
- Ventricles contract and atria relax
- Ventricles and atria relax
Why do the atria contact?
Decreases volume of chambers
Increases pressure behind AV valve (opens)
Blood pushed into ventricles
Why do the ventricles contract?
Decreases volume of chambers
Increases pressure in front of AV valve (shuts)
Increases pressure behind semi lunar valves (open)
Blood forced out into arteries
What is another name for contraction and relaxation?
Systole
Diastole
What is cardiovascular disease?
Disease associated with heart and blood vessels
How do most cardiovascular diseases start?
Atheroma formation
How does an atheroma form?
Endothelium damaged
White blood cells and lipids clump under lining
Form fatty streaks
Build up with connective tissue and harden to form fibrous plaque (atheroma)
What is Coronary heart disease?
Coronary arteries have many atheromas
Blood flow to cardiac muscle decreases
Leads to myocardial infarction
Why are atheromas dangerous?
Partially block lumen
Restrict blood flow
Blood pressure increases
What is an aneurysm?
Swelling of the artery
Atheromas form- damage and weaken arteries
Blood pressure increases
Inner layers forced through elastic layer
What happens if an aneurysm bursts?
Haemorrhage (bleeding)
What is thrombosis?
Formation of blood clot
How do blood clots form?
Atheroma forms
Atheroma plaque ruptures endothelium
Damages artery wall leaving rough surface
Platelets and fibrin accumulate
Why are blood clots dangerous?
Can cause complete blockage of artery
Debris can lead to formation of other blood clots
