BIOL273 Lecture Notes - Lecture 16: Sinoatrial Node, Skeletal Muscle, Resting Potential
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Lecture 16
C. Internal Anatomy of the Heart
Parts of the heart: 4 chambers: 2 atria, left and right are superior (?) separated by
the atrial septum and 2 ventricles that are inferior, left and right, divided by the
ventricular septum. Side by side, works in unison
Left atrium
oReceives blood from the pulmonary veins sends to ventricles
oWe have blood from the superior portion of the body via superior
vena cava to the inferior portions
oWe have well 02 blood here, the pulmonary veins carries it to the
heart? (behind, you have two of these) carries blood to the left
atrium, when it reaches it, it will send it to the left ventricle, which
upon contraction will send it to the systemic circulation (rest of the
body via aorta)
oSo we are in systematic circulation here
Left ventricle
oReceives blood from left atrium sends to atrium
Right atrium
oReceives blood from venae cavae sends to right ventricle
oSuperior to inferior vena cava?
Right ventricle
oReceives blood from right atrium sends to lungs
oBlood back to heart via pulmonary veins
Valves ensure flow is unidirectional (one-way)
oNo valves at entrance to the right & left atrium
Due to weak atrial contraction relative to ventricular
contraction
Atrial contraction compresses the veins at the entry to the
heart closes the exit to the heart & reduces backflow
During ventricular contraction
oAtria-ventricular (AV) valves tricuspid (right AV) & bicuspid/mitral
valve (left EV) (fig 14.7, you have a superior view – looking down)
Attached on ventricular side to collagenous cords chordae
tendinae
Prevents valves from being pushed back into atrium
oSemilunar valves aortic (Between left ventricle and aorta) and
pulmonary (right ventricle and…?)
During ventricular contraction these SV two are nice and open
You don’t want the blood from the ventricle into the
atria that it just game from so both the right AV and
left AV are shut
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Document Summary
Lecture 16: internal anatomy of the heart. Parts of the heart: 4 chambers: 2 atria, left and right are superior (?) separated by the atrial septum and 2 ventricles that are inferior, left and right, divided by the ventricular septum. Left ventricle: receives blood from left atrium sends to atrium. Right ventricle: receives blood from right atrium sends to lungs, blood back to heart via pulmonary veins. Valves ensure flow is unidirectional (one-way: no valves at entrance to the right & left atrium . Due to weak atrial contraction relative to ventricular contraction. Atrial contraction compresses the veins at the entry to the heart closes the exit to the heart & reduces backflow. During ventricular contraction: atria-ventricular (av) valves tricuspid (right av) & bicuspid/mitral valve (left ev) (fig 14. 7, you have a superior view looking down) Attached on ventricular side to collagenous cords chordae tendinae.