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36 terms

ECG Essentials CH 3

Electrocardiography Essentials Chapter 3
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myocardium
the heart muscle
atrium
one of the two top chambers of the heart, that receives blood from the large veins and then pumps blood into the lower chambers of the heart
superior vena cava
the main vein that drains blood from the upper part of the body into the right atrium of the heart
inferior vena cava
the main vein that drains blood from the lower part of the body into the right atrium of the heart
pulmonary vein
one of the two large vessels that returns oxygenated blood from the lungs to the left atrium
ventricle
one of the two large muscular pumping chambers of the heart located inferior to the atria
aorta
the large artery that receives blood from the left side of the heart and distributes the blood to the rest of the body
6 steps of Pulmonary circulation
1a. superior vena cava
1b. inferior vena cava
2. right atrium
3. tricuspid valve
4. right ventricle
5. pulmonary valve (semilunar)
6a. right pulmonary arteries
6b. left pulmonary arteries
6 steps of systemic circulation
7a. left pulmonary veins
7b. right pulmonary veins
8. left atrium
9. bicuspid valve (mitral)
10. left ventricle
11. aortic valve
12. aortic arch
tricuspid valve
the three-cusp valve which controls the flow of blood between the right atrium and right ventricle
pulmonic valve
the valve that is in the right ventricle and which separates the ventricle from the pulmonary artery
mitral valve
the two-cusp valve separation the left atrium from the left ventricle
aortic valve
the valve on the left side of the heart that opens to allow blood to flow from the left ventricle into the aorta
pericardial sac
the fibrous covering which completely encloses and protects the heart
electrolyte
an ion or a small particle that is positively or negatively charged, such as sodium (Na+), potassium (K+), or chloride (Cl-)
extracellular
fluid and particles outside of and surrounding the cell
intracellular
within a cell
cellular membrane
a layer of protein that surrounds a cell and keeps it separated from the surrounding fluid and cells
sinoatrial node "SA Node"
the natural pacemaker of the heart, located in the upper part of the right atrium
polarization
the resting state, meaning that there is a balance between the electrical charges on both sides of the cellular membrane and no movement of ions across the membrane occurs. "ready for action"
depolarization
a current, or wave of electricity that is created when sodium and potassium trade places across the cellular membrane. "active"
repolarization
when sodium and potassium again change places across the cellular membrane returning to their original places. "recharging"
atrioventricular node "AV Node"
special conductive tissue located in the lower right atrium that conducts electrical impulses from the atria to the ventricles
bundle of His
special conductive tissue in the middle of the septum of the heart, or inter-ventricular septum, that allows smooth and rapid conduction of the electrical impulse from the AV node to the ventricle
bundle branches
special conductive tissue fibers that extend from the Bundle of His and into the left and right ventricle
purkinje fibers
conduction fibers that branch off from the bundle branches and deliver the electrical stimulus to the ventricles, causing the ventricles to contract
systole
the period of time in which the heart muscle is contracting
diastole
the period of time when the heart muscle is relaxed
5 steps of the conduction system
1. SA Node
2. AV Node
3. Bundle of His
4. bundle branches (left and right)
5. Purkinje fibers
vascular
relating to the system of blood vessels
vena cava
large vein returning deoxygenated blood to the right side of the heart
atria
the upper chambers
pulmonary
relating to the lungs
ventricles
lower chambers or main pumping chambers
ion
very small charged particle
cardiac cycle
the series of electrical and mechanical events that comprise each heart beat