Section 4: Cardiology Flashcards
12 major structures of heart
vena cavae right atrium tricuspid valve right ventricle pulmonary valve pulmonary artery lung pulmonary vein left atrium bicuspid (mitral) left ventricle aorta
Syncytium
contractile myocites function as a single unit
autorhythmic cells (3)
specialised excitatory cells
SA node
AV node
Purkinje fibres
Desmosome
adhesion between two cells
Gap Junction
channel between cells
allows for faster depolarization
angina pectoris
severe chest pain due to cardiac ischemia, generally due to obstruction of coronary arteries
Heart attack (MI)
cardiac cell death by failure of coronary circulation
effects of nitroglycerin
Nirtoglycerin generates NO, which stimulates vasodilation
action potential of cardiac myocite duration
approx 300ms
puropse of long refractory period of myocyte
prevents sumation, prevents rigor
SA node frequency
75BPM
AV node frequency
50 BPM
AV bundle and purkinjie fibres frequency
25-40
Traditional EKG readouts:
3
I) arms
II) Right arm / left leg
III) Left arm / left leg
EKG peaks
P
QRS complex
T
P wave
Atrial depolarization
QRS complex
Ventricular depolarization
T wave
Ventricular repolarization
Organelle that stores Ca2+
Sarcoplasmic reticulum
10 steps tp EC coupling in cardiac muscle
1) Action potential from adjacent cell
2) Voltage gated (L type) calcium channel opens
3) Calcium causes calcium release from SR via ryanodine receptor (RyR)
4) Local release cause Ca spike
5) Spike causes Ca signal
6) Ca causes troponin activation
7) Relaxation occurs when Ca unbinds from troponin
8) Ca is pumped back into SR
9) Ca is eschanged with Na by NCX transporter
10) Na+ gradient is maintained with Na/K ATPase
L type sodium channel
lets Na into cardiomyocyte
Ryanodine Receptor (RyR)
allows calcium out of SR
SERCA
pulls Ca back into SR
Beta adrenergic stimulation causes
increase in L type Ca channels, RyR receptors, and SERCA
