Heart Flashcards
Where does the SVC and IVC meet?
sinus venarum
All blood from the lower extremity is drained into the IVC except for the lumbars, which are
drained into the SVC through the Azygous vein
This occurs when the mitral or tricuspid valve closes
isovolumetric contraction
The pulmonary artery has higher pressure than the R ventricle.
True
Enough pressure builds in the ventricle to blow open the pulmonic semilunar valves during
mid-systole
Which two arteries carry de-oxygenated blood?
Pulmonary artery and umbilical artery in fetus
How is blood oxygenated in the lungs?
via the Bohr effect (4 O2/molecule of hemoglobin)
Blood exits heart into the lungs through
2 pulmonary arteries
Blood exits the lung into the left atrium through
4 pulmonary veins
Which two veins carry oxygenated blood?
Pulmonary veins and umbilical vein in fetus
80% of blood passively flows into left ventricle. The other 20% needs
P-Wave-AV nodal delay
80% of blood passively flows into right ventricle. The other 20% needs
Atrial contraction
What is the correct sequence of events of left ventricular contraction?
Mitral closes → isovolumetric contraction → Midsystole → aortic valves open 70mL blood rushes into aorta → Aortic valve closes (isovolumetric relaxation)
What is the End diastolic Volume?
120mL
What is the End Systolic Volume?
50 mL
What is stroke volume (SV) in mL?
80 mL
Cardiac output is
Stroke volume ✗ Heart rate
Where does the P-Wave start?
at the SA node in the Crista Terminalis of the Right Atrium
On the EKG, where does atrial depolarization/contraction occur?
P-wave
On the EKG, what does the P-R interval represent?
AV nodal delay
On the EKG, what does the R wave represent?
isovolumetric contraction
On the EKG, ventricular depolarization/contraction is represented by the
QRS complex
On the EKG, atrial repolarization is hidden under the
QRS complex
On the EKG, what represents ventricular repolarization?
T wave
On the EKG, the U wave represents
repolarization of papillary muscle
On the EKG, i so volumetric relaxation is represented by what?
S-T segment
What does an inverted Haltered S-T segment on an EKG indicate?
Myocardial infarction
What is the main purpose of the AV node?
to delay the pulse going from the atrium to the ventricle on both sides
What are the fastest fibers in the body?
Purkinje fibers
Which heart sound is heard when AV valves closed during Isometric contraction?
1st