P wave =
Atrial depolarization
QRS complex =
Ventricular depolarization
T wave =
Ventricular repolarization
Order of heart valves
Tissue (tricuspid)
Paper (pulmonary)
My (mitral)
Assets (aortic)
Conductions of heart cycle
SA node -> AV node -> Bundle of His -> Purkinje fibers
Renin-Angiotensin-Aldosterone System (RAAS)
- 8 steps
- Renin (cells of renal arterioles)
- Angiotensin ( liver)
- Angiotensin I
- Angiotensin Converting Enzyme(ACE)(lungs/kidneys)
- Angiotensin II
- Aldosterone (adrenal cortex)
- reabsorption and retention of sodium & water
- increased blood volume & increased BP
systole
ventricular contraction
diastole
heart relaxes and and allows chambers to fill with blood
endocardium
inner layer of cardiac tissue that lines the heart chambers
myocardium
- made of muscle fibers
- responsible for pumping action of heart
- thickness varies in each chamber
epicardium
- outer layer of heart
- also the visceral pericardium
- coronary arteries are embedded in it
S1 (lub)
-occurs when ventricles contract during systole and when the mitral and tricuspid valves close
S2 (dub)
occurs during ventricular relaxation or diastole and is caused by the closing of the aortic and pulmonic valves
normal stroke volume
60-100mL
normal cardiac output
4-8 liters/minute
cardiac output equation
CO = Heart rate x stroke volume
preload
the amount of blood remaining in a ventricle at the end of the diastole or the pressure generated at the end of diastole
factors that INCREASE preload
- increased venous return to the heart
- overhydration
factors that DECREASE preload
- dehydration
- hemorrhage
- venous vasodilation
Afterload
- the amount of pressure the ventricles must overcome to eject the blood volume
- determined by pressure in the arterial system
factor that DECREASES afterload
vasodilation
factor that INCREASES afterload
vasoconstriction
the transfer of O2 and nutrients between blood and the tissue cells occurs in
capillaries
