B2 W3 Flashcards
Phase 1
Phase of cardiac action potential where sodium channels are inactivated and fast potassium efflux occurs
Which leads give an anterior view of heart?
V3 and V4
Septal view of heart from leads
V1 and V2
Phase 3 of action potential
Phase of action potential where Calcium channels inactive and delayed K+ efflux?
Which aortic sinus does not drain into one of the coronary arteries?
Right posterior
Troponin complex that inhibits myosin binding
Troponin I
Ejection fraction
Fraction of EDV ejected out by each ventricle
ECG which provides lateral view of the heart
V5 and V6
Cardiac axis
Direction of electrical current flow in the heart when ventricles are contracting
What separates the rough and smooth muscle of the right atria
Crista terminalis
Which coronary veins drain into the RA?
Great, middle, small and oblique coronary vein- this is via the coronary sinus
What demarcates marks the crista terminalis?
Sulcus terminalis
Lateral view of heart from leads
V5 and V6
Inferior view of heart
Lead III
Which arteries fill during diastole?
Only the coronary arteries which are thin. They cannot fill during systole.
ST segment
Isoelectric line between depolarisation and repolarisation
What type of receptor is an adrenergic receptor?
G-protein coupled receptor
What is the effect of noradrenaline on SAN receptors?
G protein phosphorylates phospholamban to induce Ca2+ release following cAMP cascade
What separates arterial and venous blood flow?
Transverse pericardial sinus
Which leads provide inferior view of the heart
Lead II, Lead III and avF
What does the left aortic sinus give rise to?
Left coronary artery: this splits into a LAD and a left circumflex and marginal artery
WHat does the right aortic sinus give rise to?
Right coronary artery which splits into RPD (right posterior descending) and right marginal artery
What is normal cardiac axis?
-30 to +90
Effect of Digoxin
Increases inotropy and reduces chronotropy. Reduced use due to toxicity,
Which leads have positive deflection and lateral heart view?
Lead avL, V5, V6 and I- these also provide a lateral view
Isovolumetric ventricular relaxation
Ventricles relax and pressure falls so semilunar valves close
Which veins drain the heart chambers?
Thesbian veins- smallest veins
What returns calcium to SR following contraction?
SERCA (Sarcoendoplasmic reticulum ATPASE)
What is the rough muscle of the right atria?
Musculi pectinati
What is the smooth muscle of the RA?
Sinous venarum
Which vein corresponds to the marginal coronary artery?
Small cardiac vein
Oblique pericardial sinus
What is the blind recess caused by pericardial reflections off the pulmonary veins and inferior vena cava?
Length of atrial systole?
0.1 seconds
How many pulmonary veins drain into Left Atria?
4
Which vein descends from the left atria?
Oblique coronary vein
Time between two QRS complex
RR interval
Chordae tendinae
Connects the papillary muscles to the valve
What inhibits binding of myosin?
Troponin I
Anterior coronary vein
Drains blood from R ventricle into R atria
Which calcium channels open during depolarisation?
L-type Calcium channels
Digoxin
Inhibits Na+/K+ ATPase pump. Increases intracellular sodium to cause Na+/Ca2+ exchanger to increase intracellular Ca2+ levels
