Week 7-8 review

Week 7-8 review - 1: Chiara Maruggi BILD 2 Fall 2011- Prof....

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1: Chiara Maruggi BILD 2 Fall 2011- Prof. Fortes Week 7-8 Review (Lectures 11/10/2011 and 11/15/2011) http://www.hearthealthywomen.org/images/news/heart_valves.jpg Pathway of blood through heart: Deoxygenated blood enters the right atrium via the inferior and superior vena cava flows through the tricuspid valve (semi lunar valve) enters the right ventricle is pumped into the pulmonary artery to the lungs is oxygenated at the lungs returns to the heart’s left atrium via the pulmonary veins flows through the mitral valve (semi lunar valve) and enters left ventricle is pumped into the aorta to peripheral tissues and organs Remember the valves found between the arteries and the ventricles are known as atrial valves (aortic and pulmonary valve) Diastole = heart at rest; none of the muscles are contracting Pressure in the artery when there is no contraction of the heart= diastolic pressure (60-70mmHg) Systole = contraction of the heart Maximal pressure generated= systolic pressure (pressure during ejection period) http://3.bp.blogspot.com/k6Y7KP050mc/TZSLwLmUY2I/AAAAAAAAACg/US6WL80aqWA/s1600/cardiac%2Bcycle%2Bdiagram. JPG Cycle of Heart contraction: 1. Passive filling of the ventricles. Both the atria and the ventricles are diastolic (not contracting.)
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2: Chiara Maruggi BILD 2 Fall 2011- Prof. Fortes Right side: Blood flows from the vena cava into the right atrium, through the open semi lunar valve and into the right ventricle Left side: Blood flows from the pulmonary vein into the left atrium, through the open semi lunar valve and into the left ventricle Usually longest period, lasts about 0.4seconds Main increase in heart rate is at the expense of the filling period Ventricles are being filled up (AV valves are open); no contraction 2. Contraction of the atria (systole of atria, diastole of ventricles)- serves as a way to top off the filling of the ventricle (not major source of blood entering ventricles since most of it enters during passive filling) 3. Contraction of ventricles (diastole of atria, systole of ventricles) The ventricles contract squeezing the blood increase in P. the moment the P in the ventricles is higher than the P in the atria AV valves close (lub sound) Now both the valves are closed pressure of the ventricles increases drastically once the P in the ventricles is higher than that in the arteries pushes arterial valves open gush of blood fills the arteries (this is what one feels when one feels the pulse; the amount of blood that exits= cardiac output ) arterial pressure increases systolic pressure (pressure during ejection period) Pressure Pressure= (volume of contents)/ (volume of container) If you increase the volume of the contents in a container the pressure will increase That is why having too much blood volume will increase the pressure When there is blood loss or dehydration, on the other hand, the volume of the blood decreases
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Week 7-8 review - 1: Chiara Maruggi BILD 2 Fall 2011- Prof....

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