ELECTROCARDIOGRAM (ECG) Flashcards
ELECTROCARDIOGRAM (ECG)
- Takes resting heart rate
Records the electrical changes in the myocardium during the cardiac cycle.
Waves recorded represent various chambers depolarizing and repolarizing.
P wave
results from a depolarization (contraction) of the atria.
Wave is small as contraction of the atria is to push out the last ~30% of blood.
QRS complex
results from a depolarization (contraction) of the ventricles.
Wave is large and peaks quickly as contraction of the ventricles pushes the blood to the lungs/body.
T wave
results from a repolarization (relaxation) of the ventricles
Cardiac veins (sometimes called coronary veins)
paths parallel coronary arteries - drain blood that has passed through the myocardial capillaries.
These veins join the coronary sinus which returns blood into the right atrium.
aortic branches
the left and right coronary arteries
supply blood to the heart tissue.
The heart (specifically the myocardium), as well as other body tissues, needs a constant supply of freshly oxygenated blood, therefore the heart beats continually.
Coronary Heart Disease
is usually coronary atherosclerosis
- feed the heart tissue itself
- heart pumps out oxygenated blood
- feed heart tissue itself
Atherosclerosis
a pathological process resulting in the buildup of plaque.
- when the arteries are blocked
- starts with cholesterol then turns into plaque (cannot remove plaque)
(Plaque is a composed of connective tissue, smooth muscle cells, and cholesterol.)
functional syncytium
A mass of merging muscle fibers that act as a unit
Atrial syncytium
mass of muscle fibers along the atrial walls
Ventricular syncytium
mass of muscle fibers along the ventricular walls.
Arteriosclerosis
- decreased elasticity of arterial walls and narrowing of arterial lumens
Lumen
hole or opening
Collagen
allows vessel to expand and recoil
syncytium
when 1 fiber contractions, ALL of them do
