Anatomy and Function of the Heart Valves
What are heart valves?
The heart consists of 4 chambers, 2 atria (upper chambers) and 2 ventricles (lower chambers). Blood passes through a valve before leaving each chamber of the heart. The valves prevent the backward flow of blood. Valves are actually flaps (leaflets) that act as one-way inlets for blood coming into a ventricle and one-way outlets for blood leaving a ventricle. Normal valves have 3 flaps (leaflets), except the mitral valve, which only has 2 flaps. The 4 heart valves include:
|Click image to enlarge|
Tricuspid valve. This valve is located between the right atrium and the right ventricle.
Pulmonary valve. The pulmonary valve is located between the right ventricle and the pulmonary artery.
Mitral valve. This valve is located between the left atrium and the left ventricle. It has only 2 leaflets.
Aortic valve. The aortic valve is located between the left ventricle and the aorta.
How do the heart valves function?
As the heart muscle contracts and relaxes, the valves open and shut, letting blood flow into the ventricles and atria at alternate times. The following is a step-by-step description of how the valves function normally in the left ventricle:
When the left ventricle relaxes, the aortic valve closes and the mitral valve opens, to allow blood to flow from the left atrium into the left ventricle.
The left atrium contracts, allowing even more blood to flow into the left ventricle.
When the left ventricle contracts again, the mitral valve closes and the aortic valve opens, so blood flows into the aorta.
What is heart valve disease?
Heart valves can malfunction in several ways, including:
Regurgitation is leakage of the valve. This means the valve doesn’t close completely, causing the blood to flow backward through the valve. This results in leakage of blood back into the atria from the ventricles (in the case of the mitral and tricuspid valves) or leakage of blood back into the ventricles (in the case of the aortic and pulmonary valves).
Stenosis is narrowing of the valve. With stenosis, the valve opening is narrowed and the valve doesn’t open properly, inhibiting the ability of the heart to pump blood across the narrowed valve due to the increased force required to pump blood through the stiff (stenotic) valve(s).
Atresia. This means the valve opening doesn’t develop normally as a child, preventing blood from passing from an atria to a ventricle, or from a ventricle to the pulmonary artery or aorta. Blood must find an alternate route, usually through another existing congenital (present at birth) defect, such as an atrial septal defect or a ventricular septal defect.
1351Baby shower guest sign in ideas
2533Boy baby shower decorations ideas
1607Girl baby shower favors ideas
1791TOP 10 Girl baby shower themes ideas for 2017
600Baby shower fruit tray ideas
3923Baby shower snack ideas pinterest
4319Baby shower afternoon tea ideas
1909Purchase The Special Twin Baby Shower Cakes From Your Local Stores
4291High tea baby shower ideas – 10 ways to have a High tea baby shower party!
2553TOP 10 Baby girl baby shower food ideas
218710 Useful Triplet baby shower ideas for you!
2463Baby shower ideas pinterest boy
554Welcoming a Baby Angel in Style with the Best Baby shower souvenir ideas
2041Planning a Baby shower program ideas – detailed guide
4315Baby shower centerpieces ideas pictures – 10 methods to brighten your baby shower party
23689It is Safe to Eat Raw Meat – A Guide to Choosing the Right Type
3165Baby shower charades ideas
4327Baby shower onesie ideas – 10 secrets to know
4303Baby shower ideas melbourne
3697Star baby shower ideas
4159Baby shower room ideas
1721Baby shower prize ideas for guests
532Baby shower corsage ideas
2379125 Paleo Breakfast Ideas
1155Garden baby shower ideas
3389Table decoration ideas for baby shower
4271Baby shower nappy cake ideas
21731Week 25 of Pregnancy – The Pregnancy Excitement
4281Baby shower favors ideas cheap
1757Brunch food ideas for baby shower
23722Security Blankets and Other Comfort Objects
706Baby shower table decoration ideas
3763Sentimental baby shower ideas
1865Baby shower food ideas for boys
676Baby boy shower theme ideas
18Boy baby shower ideas