Quiz 5: cardiology (26) Flashcards
cardiac cycle
- SA node releases wave, depolarizing the LA and RA causing atrial systole.
- AV node temporarily stops the wave from entering the ventricles.
- Bundle of His, the wave passes down the bundle of his or bundle branches and on to the
- Purkinje fibers which spread the depolarization through the ventricles, resulting in ventricular systole. At the same time, the atria are relaxing= atrial diastole.
the pressure in the ventricles build up. once greater than the pressure in the arteries, the blood is forced back up toward the atria, which forces the AV valves closed. (LUBB)The pressure continues building which then forces the semilunar valves open.
about half the blood is ejected into arteries. Then the ventricles repolarize, resulting in ventricular diastole. The pressure in the ventricles then drops below that in the arteries so the blood pushed back, forcing the semilunar valves closed. (DUP)
- this entire process takes about 1/10 of a second. called the systolic phase.
- the diastolic phase is about 7/10ths of a second and occurs before the heart repeats the systolic phase.
veins and arteries
- veins bring blood to heart
- arteries bring blood away from heart.
-generally, veins carry deoxygenated blood, and arteries carry oxygenated blood. The pulmonary veins carry oxygenated blood and the pulmonary artery carries deoxygenated blood.
lungs–> o2 blood to pulm. veins to LA–>LV–> aorta–>systemic circuit–>Vena Cava–>RA–>RV–>Pulm. Trunk–> deoxy blood–> lungs
heart tissue
- pericardium–sack around heart
- parietal–outer layer of sack
- visceral pericardium/epicardium–inner layer of sack, on heart muscle
- myocardium–actual heart tissue/muscle
- endocardium–lines heart chambers
cardiac muscle
- striated
- autoergonic (self stimulating_
- myocytes=cells connected through intercalated discs and desmosomes and gap junctions
- cardiac muscle cannot repair itself. once damaged, it is replaced by fibrous tissue.
- heart is like one big muscle cell
