Flashcards in The cardiovascular system/the structure of the heart Deck (15):
what are the features of an alveolus that make it effective at gas exchange?
Features of an alveolus that help gas exchange:
- folded membrane gives large surface area
- the cells of the capillary and the alveoli are thin and flattened so diffusion distance is very short
- good blood supply to maintain concentration gradient
- moist lining so gases can dissolve
which blood vessel takes blood away from the heart towards the lungs?
The pulmonary artery takes blood away from the heart towards the lungs
which valves stop the blood flowing back into the ventricles from the arteries?
Describe what a natural pacemaker is
A natural peacemaker is controlled by a group of cells found in the right atrium of your heart that acts as your natural pacemaker. Also it is a pulse generator.
What are the problems if the natural pacemaker stops working?
If the natural pacemaker stops working properly, this can cause serious problems. If the heart beats too slowly, the person affects will not get enough oxygen. If the heart beats too fast, it cannot pump blood properly.
Describe how an artificial pacemaker works
An artificial peacemaker works by an electrical device which is implanted into your chest. They are usually very small and attach to your heart by two wires. The artificial pacemaker sends strong, regular electrical signals to the heart to make it beat properly.
Heart valves can become damaged. If this happens then the flow of blood through the heart is affected so they may have to be replaced. Currently, there are two options for a replacement heart valve: a mechanical valve or a biological valve.
Write down a list of advantages and disadvantages of having a mechanical heart valve rather than a biological one. Remember to consider personal, social and economic factors:
-These valves are made of lightweight, strong, and durable materials, such as titanium.
-They will last 20–30 years before a replacement is needed.
-Mechanical valves are cheaper than biological ones.
-Because of the materials in the valve, it is likely that blood clots will form on it.
-This could stop it from working.
-Patients will need to take blood thinning drugs every day for the rest of their lives.
-Even with the thinning drugs, there is also the risk that a blood clot will form and then move to block a blood vessel, which could cause a stroke or heart attack.
Biological Heart Valves
Biological valves are created from animal valves or other animal tissue that is strong and flexible, usually from pigs. They can last 10–20 years. The risk of blood clotting is very small, so patients don't usually require the long-term use of medication. Mechanical valves are cheaper than biological ones, but this does not take into account the long-term use of drugs.
In what situation might someone need an artificial heart?
When a person needs a heart transplant.
What are some of the disadvantages of having an artificial heart
(consider medical as well as social issues)
But sometimes it is not enough to restore a person's health.
Many people die before they get a chance to have a heart transplant (because of the wait).
There is always a risk of the blood clotting in an artificial heart, which can lead to death.
What are some of the advantages of having an artificial heart?
Scientists have developed temporary hearts that can support your natural heart until it can be replaced.
These artificial hearts need a lot of machinery to keep them working.
This new technology gives people a chance to live a relativity normal life while they wait for a heart transplant.
Artificial hearts can also be used to give a diseased heart a rest, so that it can recover.
Identify/Label the structures of the heart
1. Vena cava (from body)
2. Semilunar valves
3. Right atrium
4. Tricuspid valve
5. Right ventricle
6. Left ventricle
7. Bicuspid valve
8. Left atrium
9. Pulmonary vein (from lungs)
10. Pulmonary artery (to lungs)
11. Aorta (to body)
Explain why the left ventricle wall is thicker than the right ventricle
The left ventricle wall is thicker than the right ventricle wall because the muscle of the the left ventricle is noticeably thicker than the wall of the right ventricle. This allows the left ventricle to develop the pressure needed to force the blood through the arterial system all over your body. The blood leaving the right ventricle moves through the pulmonary arteries to your lungs, where high pressure would damage the delicate capillary network where gas exchange takes place.