mitral valve

Examples of mitral valve in the following topics:

• Operation of Atrioventricular Valves

  • Valves open or close based on pressure differences across the valve.
  • The mitral valve is on the left side of the heart and allows the blood to flow from the left atrium into the left ventricle.
  • The relaxation of the ventricular myocardium and the contraction of the atrial myocardium cause a pressure gradient that allows for rapid blood flow from the left atrium into the left ventricle across the mitral valve.
  • The mitral annulus, a ring around the mitral valve, changes in shape and size during the cardiac cycle to prevent backflow.
  • Describe the operation of the atrioventricular valves: bicuspid (mitral) and tricuspid

• Heart Valve Disorders

  • Valvular heart disease is any disease process involving one or more of the valves of the heart (the aortic and mitral valves on the left and the pulmonary and tricuspid valves on the right).
  • Valvular heart disease includes aortic and mitral valve disorders, and pulmonary and tricuspid valve disorders.
  • Pulmonary valve diseases are the least common heart valve disease in adults.
  • The most common types of pulmonary valve diseases are: pulmonary valve insufficiency, pulmonary valve incompetence, and pulmonary valve regurgitation.
  • Both tricuspid and pulmonary valve diseases are less common than aortic or mitral valve diseases due to the lower pressure those valves experience.

• Pumps and the Heart

  • The septum divides the left and right side of the heart, while the valves of the heart ensure that blood only flows in one direction.They include the tricuspid valve-found between the right atrium and the right ventricle-and the mitral valve-found between the left atrium and the left ventricle.
  • The list of heart valves also includes the semi-lunar valves, which are located at the bottom of the aorta and pulmonary artery.
  • Strong tendinous chords attached to valves prevent them from turning inside out when they close.
  • The heart beat can be heard as a sound that the valves make when they close.
  • The ‘lub' sound is made when the atrio ventricular valves close and the ‘dub' sound is made when the semi lunar valves close.

• Heart Sounds

  • The two major heart sounds are "lub" (from the closure of AV valves) and "dub: (from the closure of aortic and pulmonary valves).
  • The closing of the heart valves produces a sound.
  • The first heart sound, called S1, makes a "lub" sound caused by the closure of the mitral and tricuspid valves as ventricular systole begins.
  • There is a very slight split between the closure of the mitral and tricuspid valves, but it is not long enough to create multiple sounds.
  • S2 is split because aortic valve closure occurs before pulmonary valve closure.

• Systemic and Pulmonary Circulation

  • The blood is then pumped through the tricuspid valve into the right ventricle.
  • From the right ventricle, blood is pumped through the pulmonary valve and into the pulmonary artery.
  • Once entering the left heart, the blood flows through the bicuspid valve into the left ventricle.
  • The blood is then pumped through the mitral valve into the left ventricle.
  • From the left ventricle, blood is pumped through the aortic valve and into the aorta, the body's largest artery.

• Blood Supply to the Lungs

  • The vena cava fills the right atrium with blood, which then ejects blood into the right ventricle by passing through the tricuspid valve.
  • After blood fills in the right ventricle, it contracts and pumps the blood through the pulmonary valve, and into the pulmonary arteries.
  • This blood then enters and fills inside the left atrium, which pumps it through the mitral valve (also called bicuspid) into the left ventricle.
  • The blood fills inside the left ventricle and is then pumped through the aortic valve into the aorta, which marks the beginning of systemic circulation.

• Structures of the Heart

  • The heart pumps blood through the body with the help of structures such as ventricles, atria, and valves.
  • This deoxygenated blood then passes to the right ventricle through the right atrioventricular valve (tricuspid valve), a flap of connective tissue that opens in only one direction to prevent the backflow of blood.
  • The valve separating the chambers on the left side of the heart is called the biscuspid or mitral valve (left atrioventricular valve).The blood passes through the bicuspid valve to the left ventricle where it is pumped out through the aorta, the major artery of the body, taking oxygenated blood to the organs and muscles of the body.
  • Once blood is pumped out of the left ventricle and into the aorta, the aortic semilunar valve (or aortic valve) closes, preventing blood from flowing backward into the left ventricle.
  • One-way valves separate the four chambers.

• Heart Murmurs

  • Heart murmurs are pathologic heart sounds indicative of valve and blood flow abnormalities.
  • Yet most heart problems do not produce any murmur and most valve problems also do not produce an audible murmur.
  • Anatomical sources of heart murmurs include stenosis of the bicuspid aortic valve which tends to appear between 40 and 70 years of age, and stenosis of the tricuspid aortic valve where symptoms more likely to appear after 80 years of age.
  • The first heart sound is caused by the atrioventricular valves--Mitral (M) and Tricuspid (T)--and the second heart sound is caused by the semilunar valves--Aortic (A) and Pulmonary/Pulmonic (P).
  • Heart murmurs are often the result of leaky valves.

• Chambers of the Heart

  • Blood passively flows into the atria without passing through valves.
  • The atria and ventricles are separated by the mitral and tricuspid valves.
  • The chordae tendinae are elastic tendons that attach to the valve from the ventricles and relax during atrial systole and ventricular diastole, but contract and close off the valve during ventricular systole.
  • There are no atrial inlet valves to interrupt blood flow during atrial systole.
  • During ventricular systole, the ventricles contract, pumping blood through the semi-lunar valves into systemic circulation.

• Operation of Semilunar Valves

  • These valves do not have chordae tendineae, and are more similar to valves in veins than to atrioventricular valves.
  • The semilunar valves act in concert with the atrioventricular valves to direct blood flow in the heart.
  • When the atrioventricular valves are open, the semi lunar valves are shut and blood is forced into the ventricles.
  • This anterior view of the heart indicates the semilunar valves, the aortic and pulmonary valves.
  • Describe the operation of the semilunar valves, the aortic and pulmonary valves