1. Copyright © 2008 by Youth Take Heart
We Got the Beat
Copyright © 2008 by Youth Take Heart

2. ? What does the human heart look like?
*Use the clay you were given to model
What you think a heart looks like
Goal: To explain the structure and function of the human
Heart. ?

3. What is the function of the
human heart?

4. What features do they have in Common?
Different kinds of pumps:
Bike pump Camera Duster Turkey Baster
What features do they have in
Common?

5. They all…..
Have an open chamber (air space)
Have flexible walls
Move fluids in and out
Have valves

6. Common Valves Car Tire Air Mattress Bike Tube
Bike Tube

7. Play Button to open link
Heart Animations:
HABITS OF THE HEART ©
Click (or Right Click)
Play Button to open link

8. Revising your heart model:
How has your thinking changed?
Make any changes to your heart model that you would like.
Sketch and describe the changes you made in your science notebook.
Explain why you changed your model.

9. Click (or Right Click) Play Button to open link
Background Reading:
“Your Heart & Circulatory System”
Click (or Right Click) Play Button to open link

10. ----- Oxygen-rich blood
Heart Diagram:
1. Label the following parts:
atria, valves, ventricles, vena cava and aorta
2. Draw the path of the blood traveling through the heart (use color code below)
----- Oxygen-rich blood
----- Oxygen-poor blood
3. Explain to your partner the path the blood takes as it travels through the heart

11. Brainstorm: How could a pump fail?
What can go wrong with your heart as a pump?
*Try to think of at least 3 problems a pump/heart could develop

12. Design Challenge Design a solution to this problem:
Amy, a 13 year old student at Deer Ridge Middle School, recently went for a physical for volleyball. She was born with congenital aortic valve stenosis.
Congenital aortic valve stenosis is a narrowed valve in the aorta.
When she was born, Amy’s body wasn’t getting as much blood as it could from the left ventricle.
Her replacement valve, which comes from the outside of a pig heart, has become calcified. Calcium has built up on the aorta. (See next slide.)
It is uncommon, but not unusual for a child or young adult to require an artificial heart valve.  One example is congenital aortic valve stenosis, which is narrowing of the aortic valve resulting in obstruction to flow out of the left ventricle (the main chamber that pumps blood to the body). Normally the aortic valve has 3 leaflets (flaps).  Rarely, people are born with a valve that has only a single leaflet, in which case they may require either balloon valvuloplasty or surgical  valve replacement in early childhood. Bicuspid (2 leaflet) aortic valves are actually the most common congenital heart defect, and are present in about 1% of the population.  These patients can develop valves that are either leaky or stenotic, and in either case may require surgical valve replacement, either in young adulthood or, more commonly, in middle age. There are 3 general types of replacement valves: 1. Mechanical, in which the leaflets of the valve are tilting discs made of carbon fiber composite and supported by metal struts.  These valves are not popular in kids because they require that patients be on blood thinners (coumadin) to prevent formation on the valve surface of blood clots that could either prevent the valve from opening or closing normally or break off and travel to the brain to cause a stroke.  Because kids are very active, they are at high risk for bleeding problems while on the blood thinners.  Also, they have to be very meticulous in taking their medication and require frequent blood tests to make sure that the level of blood thinning is neither too high or too low.  These valves typically last about 15 years before they wear out and require replacement.  They also do not grow as the patient grows, so for that reason also are not favored in very young children. 2.  Bioprosthetic, in which the valve leaflets are fashion from pericardial tissue (pericardium is the sack that surrounds the heart) obtained from pigs or cows.  An advantage of these valves is that they do not require blood thinners.  However, they tend to develop calcium deposits and wear out more quickly in kids than do mechanical valves.  Also, like mechanical valves, they do not get bigger as the patient grows. 3.  Homografts, which are human valves obtained from cadavers.  These are the ideal valves in very young patients, because they do grow as the patient grows.  Also, they do not require patients to be on blood thinners.  However, as you might imagine, the supply of this type of valve is quite limited.  Therefore, it might be particularly useful to discuss this type of valve in your class for 2 reasons:  a) It highlights the advantages of using a biological material for valve replacement (lack of need for blood thinners and ability to grow as the patient grows) and b) to discuss organ donation. Kevin D. O'Brien, M.D. Professor of Medicine
Division of Cardiology
University of Washington

13. Calcified Aortic Heart Valve
Calcification on the valve
Calcification on the valve
Opening in valve where blood leaks backward
Image courtesy of CDC/ Dr. Edwin P. Ewing, Jr.
Aortic valve viewed from above

14. Amy’s doctor said,
“Unfortunately you will need another valve replacement to fix your blood flow problem. We have hired a team of bioengineers to design an artificial valve for you. You won’t be able to play this year, but with any luck, you should be ready for the volleyball team next season!”

15. Normal heart vs. Pulmonary valve stenosis

16. Examples of Artificial Valves
Photos courtesy of Rachel Hervey

17. Final Thoughts
Two positives of the lesson
One wish