Week 1 Flashcards
Structures on the right side of the heart, or right heart, pump blood through the lungs and termed the
pulmonary circuit
The left side of the heart, or left heart, sends blood throughout the ________, which supplies
all of the body except the lungs
systemic circulation
thickest layer of the heart wall
myocardium
Which chamber of the heart has the thickest myocardium?
left ventricle
During _____________ the two AV valves (tricuspid and mitral valves) open and blood flows from the relatively higher pressure in the atria to the lower pressure in the relaxed ventricles.
ventricular relaxation
valves close and prevent backflow into the atria as the ventricles contract
ventricular contraction
open when intraventricular pressure exceeds aortic and pulmonary pressures and blood flows out of the ventricles and into the systemic and pulmonary circulations
semilunar valves of the heart (aortic and pulmonic valves)
blood fills the ventricles
-period of relaxation
distole
-contraction
-propels the blood out of the ventircles
Systole
The Five Phases of the Cardiac Cycle
- Ventricular diastole-opening of the mitral and tricuspid valves and then ventricular filling from the atria occurs
- Ventricular systole begins with “isovolumetric contraction; contraction pushes AV valves shut
- When ventricular pressure exceeds pulmonary artery and aorta, the semilunar valves open and ventricular ejection occurs
- ventricular relaxation- all valves closed
- L ventricle pressure falls below atrial- mitral and tricuspid valves open and passive ventricular filling occurs.
Ventricular diastole is the same as atrial
systole
supply oxygen and other nutrients to the myocardium, heart structures are nourished by vessels of the systemic circulation, the coronary circulation
coronary arteries
which coronary artery has the greatest flow
right coronary artery has greater flow
-in 70% of individuals
The left coronary artery generally divides into two branches—
- the left anterior descending artery
- circumflex artery.
delivers blood to portions of the left and right ventricles and much of the interventricular septum.
left anterior descending artery
supplies blood to the left atrium and the lateral wall of the left ventricle.
circumflex artery
travels behind the pulmonary artery, and extends around the right heart to the heart’s posterior surface, where it branches to the right atrium and ventricle.
R coronary artery
connections, or anastomoses, between branches of the same coronary artery or connections of branches of the right coronary artery with branches of the left.
collateral arteries
-protects the heart from ischemia
New collateral vessels are formed through two processes:
- arteriogenesis (new artery growth branching from pre-existing arteries)
- angiogenesis (growth of new capillaries within a tissue).
SA node loaction
unction of the right atrium and superior vena cava, just above the tricuspid valve.
SA node generates about 60 to 100 action potentials per minute depending on age and physical condition.
SA node generates about 60 to 100 action potentials per minute depending on age and physical condition.
caused by the movement of ions, including sodium, potassium, calcium, and chloride, across cardiac cell membranes.
depolarization
rapid sodium entry into the cell. (the inside of the cell becomes LESS negative lowering the membrane potential)
depolrization
property of generating spontaneous depolarization to threshold, enables the SA and AV nodes to generate cardiac action potentials without any stimulus
automacity
