Task
A Draw up a table and Title it Artifical Heart Valves
Some of the doctors and scientists who develop artificial heart valves try to copy nature, believing that valves work best if they are modelled on nature. Others believe that it is not important to worry about what a valve looks like but to make a valve that functions properly.
Use these below as headings and put all information in a table
- Type of artificial heart valve
- Description e.g. what is it made of?How does it work?
- Function e.g When would this type of valve be used? What are its advantages?
- Disadvantages of this type of heart valve
Below is an example of what is required for this question
|
Type of artificial valve |
Description/Structure |
Function |
Disadvantage |
|
Mechanical valves |
A ball or disc is placed so it has restricted movement between a ring and a cage. As the heart contracts, the ball is forced towards the cage. As the heart relaxes, the back-flow of blood forces the ball against the ring. |
These types of valves function to allow blood flow through the valve opening and around the ball or disc as the heart contracts and prevent back flow of blood as the heart relaxes. |
|
|
e.g. tilting disc or bileaflet valves. |
A disc or some leaflets swing open as blood flows in the required direction and close when blood flows back. |
These types of valves function more efficiently as there is less obstruction to blood flow from a ball or floating disc. They also last longer as there is less fatigue resulting from repeated ramming against a cage. |
|
B Complete Questions on heart valves (page 18 in your worksheets)
C Answer the questions below
Question 1
Imagine you are 47 years old. You have been experiencing shortness of breath, seemingly constant exhaustion and a fluttering feeling in your chest. You are referred to a cardiac specialist. The cardiac specialist tests the electrical signals within your heart and recommends the implantation of a pacemaker. You listen to her explanation about the procedure.
In two paragraphs or less, write a concise explanation of a pacemaker, its parts, installation, function, length of surgery and adjustments after surgery that the cardiac specialist is likely to tell you. Remember to think like a cardiac specialist as you are writing your explanation. Use the terms they would when dealing with a patient and remember to explain all the points outlined in the previous paragraph.
Question 2
Heart valves have a specific function. Their structure is closely related to their function.
In one paragraph, explain their structure, how heart valves work and relate this to their function. You may use diagrams in the margin to help with your answer.
Question 3
Imagine you are a patient experiencing tiredness and shortness of breath. Your doctor explains you are likely to have faulty heart valves, although he doesn’t have time to explain it to you.
You go home and search the Internet to find out what could be wrong with your heart valves. Imagine that you find a webpage that fully explains two problems associated with faulty heart valves that you could have. Use the space provided below to create a web page that you think fully explains the two possible heart valve conditions. Be as creative and innovative as you like. This page has been left blank for this purpose
Question 4
Draw an example of a replacement heart valve below
Question 5
Explain two problems associated with replacement heart valves encountered by doctors through history.
Question 6
State three materials currently used in heart valves and explain why these materials are suitable for use in transplants