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RET 1125 CH 1 2 ELECTROP SOLHYUSTIOIOLNSOGY 10 0 OF% TVHEERIF HEIED!AR!T EXAM WITH COMPLETE
heart contracts by _____ and ____ action potentials - ANSWER generating andpropagating
electrical currents that travel across cell membranes of the heart - ANSWER actionpotentials
in neurons, a transmitted action potential is called - ANSWER nerve impulse when the heart is relaxed (not generating an action potential), cardiac muscle fibers arein a - ANSWER polarized or resting state (diastole)
filling state is taking place** filling w/blood for next contraction electrical difference between electrolytes inside cell membranes and electrolytesoutside of cell membranes - ANSWER resting membrane potential (RMP)
primary electrolytes responsible for electrical difference across RMP - ANSWERPotassium (K+) Sodium (Na+) Calcium (Ca2+) concentration is greatest inside cardiac cell (151 mEq/L) - ANSWER K+ (potassium) about 4 mEq/L outside cell
concentration is greatest outside cardiac cell - ANSWER Na+ (sodium) and Ca2+(Calcium)
concentration outside cardiac cell is about 144 mEq/L - ANSWER Na+ (sodium) about 7 mEq/L inside cell concentration outside cardiac cell is about 5 mEq/L - ANSWER Ca2+ (calcium) less than 1 mEq/L inside cell when cardiac cell is in resting/polarized state, inside of cell is _____ and outside of cell is______ - ANSWER inside: negatively charged with K+ ions outside: positively charged with Na+ ions for each Na+ ion that diffuses into the cell, about _____ K+ ions diffuse out of the cell -ANSWER 75 K+
deficiency of positive cations inside cell; cell has a negative charge difference between electrolytes inside cell and electrolytes outside cell generates an_______ - ANSWER electrical charge
potential force of resting membrane potential (RMP) is measured in - ANSWER millivolts(mV)
1 mV = 0.001 V RMP of myocardial cells is about -90 mV
K continues to flow out Resting or polarized state - ANSWER Phase 4; ion pumps inside cell remove Na, bring K back in, and remove Ca the heart is composed of two types of cardiac cells - ANSWER contractile muscle fibers- squeeze specialized "pacemaker" cells (autorhythmic cells) - transmit electrical impulse hearts cardiac cells have the following four specific properties - ANSWER automaticity,excitability, conductivity, and contractility
AECC unique ability of cells in SA node (pacemaker cells) to generate action potential withoutbeing stimulated - ANSWER automaticity
ability of cell to reach its threshold potential and respond to stimulus or irritation -ANSWER excitability (irritability)
ability of heart cells to transmit electrical current from cell to cell throughout entireconductive system - ANSWER conductivity
ability of cardiac muscle fibers to shorten and contract in response to electricalstimulus - ANSWER contractility
the sinoatrial node is seen as the - ANSWER co-pilot
components of conductive system - ANSWER Sinoatrial node (SA): HR 60- Atrioventricular (AV) junction: HR 40- Bundle of HisRight and left bundle branches Purkinje fibers - HR <40 (not life sustaining) electrical cycle of heart begins with - ANSWER SA node or pacemaker SA node initiates cardiac contraction by producing electrical impulse that travelthrough - ANSWER left and right atria
in right atrium, impulse is conducted through anterior, middle, and posterior ____ -ANSWER internodal tracts; all three pathways become one at AV junction
conducts impulses from SA node directly to left atrium - ANSWER Bachmann's Bundle impulse by SA node has right and left atria contract simultaneously, forcing blood tomove into - ANSWER ventricles
in normal heart, entire heart depolarizes in - ANSWER 0.22 seconds AV junction (AV bundle) sends impulse from atria to ventricles via - ANSWER bundle ofHis
bundle of his enters intraventricular septum and divides into - ANSWER left and rightbundle branches
soft sound- recommend echocardiogram heart murmurs - ANSWER due to turbulent blood flow/regurgitation of blood flow sounds like "whooshing" sound can be due to heart valve defects/congenital heart abnormalities
