J Aehlert
Automaticity - ANSWER:the ability of pacemaker cells to create an electrical impulse
without being stimulated from another source.
Increased blood concentrations of ______ increase automaticity, while decreased
blood concentrations of _______ decrease automaticity. - ANSWER:Calcium /
Potassium
When the inside of a cell is more negative than the outside, the cell is said to be in a
_______________ state - ANSWER:Polarized
When a cell is at rest, ______ leaks out of it - ANSWER:K+ (Potassium)
The movement of charged articles across a cell membrane that causes the inside of
the cell to become positive is called _______________ - ANSWER:depolarization
Depolarization, which is an electrical event, must take place before the heart can
____________ - ANSWER:contract and pump blood (mechanical)
a 'P WAVE' represents: - ANSWER:Atrial Depolarization.
'QRS' complex is recorded when: - ANSWER:The ventricles are stimulated.
(depolarization)
The movement of charged particles across a cell membrane in which the inside of
the cell is restored to its negative charge is called: - ANSWER:Repolarization
'ST' segment and 'T' Wave are recorded when - ANSWER:Ventricular Repolarization
occurs
Refractoriness - ANSWER:term used to describe the period of recovery that cells
need after being discharged before they are once again able to respond to a stimulus
Absolute Refractory Period (ARP) - ANSWER:cell will not respond to further
stimulation within itself. Corresponds to the time needed for the reopening of
channels that allow the entry of sodium and calcium into the cell
Sinoatrial Node (SA NODE) - ANSWER:Located in the upper posterior part of the right
atrium where Superior VC and Right Atrium meet. Pacemaker of the heart. 60-100
BPM. Can increase to around 150 due to sympathetic stimulation
Ectopic - ANSWER:"out of place"
, Terms used to describe an impulse that originates from a source other than the SA
Node: - ANSWER:Ectopic or Latent
Atrioventricular Node (AV) - ANSWER:Located in the floor of the right atrium
immediately behind tricuspid valve. Size varies among individuals. Supplied by
branch of RCA in most people. Conduction begins before atrial depolarization is
completed.
AV Node is divided into three functional regions: - ANSWER:1. Atrionodal Region
(AN). located between atrium and rest of node. 2. Nodal Region (N). Compact AV
node where transitional messages merge with midnodal cells. 3. Nodal-His (NH) or
lower region where the fibers of the AV node gradually merge with the bundle of
His.
Bundle of His - ANSWER:"Common Bundle" or "AV Bundle". Continuation of the AV
node and connects the AV Node with the bundle branches.
The AV Node and the Bundle of His are called the: - ANSWER:AV Junction
His-Purkinje System - ANSWER:refers to the bundle of His, bundle branches and the
Purkinje fibers.
Accessory Pathway - ANSWER:The abnormal route taken when the AV Node and
bundle are bypassed by an abnormal pathway.
The right bundle branch: - ANSWER:is thin and travels to the apex of the right
ventricle
The left bundle branch - ANSWER:spreads the electrical impulse to the
interventricular septum and left ventricle. Is thicker that right and splits into divisions
called fascicles on the subendocardial surface of the left side of the interventricular
system
The R and L Bundle Branches divide into smaller and smaller branches and eventually
into: - ANSWER:Purkinje Fibers
Purkinje Fibers - ANSWER:Large diameter and abundant concentration of gap
junctions, which enable rapid propagation of electrical impulses.
Standard Limb Leads - ANSWER:I, II, III
Lead I Views - ANSWER:Lateral Surface of the left ventricle. Records difference in
electrical potential between the left arm (+) and the right arm (-) electrodes.
Lead II Views - ANSWER:Inferior surface of the left ventricle. Records difference in
electrical potential between the left leg (+) and the right arm (-) electrodes.