The cardiovascular system/the structure of the heart

Question 1

what are the features of an alveolus that make it effective at gas exchange?

Answer 1

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

Question 2

which blood vessel takes blood away from the heart towards the lungs?

Answer 2

The pulmonary artery takes blood away from the heart towards the lungs

Question 3

which valves stop the blood flowing back into the ventricles from the arteries?

Answer 3

Tricuspid valve

Question 4

Artificial Pacemakers

Describe what a natural pacemaker is

Answer 4

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.

Question 5

Artificial Pacemakers

What are the problems if the natural pacemaker stops working?

Answer 5

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.

Question 6

Artificial Pacemakers

Describe how an artificial pacemaker works

Answer 6

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.

Question 7

Heart Valves

Answer 7

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.

Question 8

Heart Valves
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:

Answer 8

Advantages:
-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.
Disadvantages:
-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.

Question 9

Heart Valves

Biological Heart Valves

Answer 9

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.

Question 10

Artificial Hearts

In what situation might someone need an artificial heart?

Answer 10

When a person needs a heart transplant.

Question 11

Artificial Hearts
What are some of the disadvantages of having an artificial heart
(consider medical as well as social issues)

Answer 11

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.

Question 12

Artificial Hearts

What are some of the advantages of having an artificial heart?

Answer 12

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.

Question 13

Identify/Label the structures of the heart

Answer 13

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)

Question 14

Explain why the left ventricle wall is thicker than the right ventricle
wall

Answer 14

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.

Question 15

Explain why humans are said to have a double circulatory system

Answer 15

Humans are said to have a double circulatory system because in humans and other mammals the blood vessels are arranged into a double circulatory system. One transport system carries blood from your heart to your lungs and back again. This allows oxygen and carbon dioxide to be exchanged with the air in the lungs. The other transport system carries blood from your heart to all other organs of your body and back again. A double circulation like this is vital in warm-blooded, active animals such as humans. It makes our circulatory system very efficient. Fully oxygenated blood returns to the heart from the lungs. This blood can then be sent off to different parts of the body at high pressure, so more areas of your body can receive fully oxygenated blood quickly.