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18 Cards in this Set

  • Front
  • Back
Cardiac Cell Structure
-cylindrical

-striations: same filaments as skeletal muscle
:actin, tropomyosin, troponin, myosin
cardiac cell structure
-Intercalated Disks
-connections between cardiac cells

-Ca2+ binded to troponin

-many desmosomes-keep cells together

-many gap junctions-help spread electrical activations
Circulatory Flow Circuit
-double circuit

vena cava -> RA -> RV -> lungs -> LA -> LV -> body -> vena cava
Cardiac Activation Structures
-5% autorhythmic cells in the heart

-fastest depolarizer reaches threshold first and starts heart beat
cardiac activation structures
-atria
-right atrium - where heartbeat is initated
cardiac activation structures
-atria
-SA Node
-right atrium

-autorhythmic-depolarizes to threshold with no stiumulus

-no stable membrane potential
cardiac activation structures
-atria
-Atrial Muscle
-SA node AP's spread to atrial muscle by gap junctions

-contracts forcing blood into ventricles
cardiac activation structures
-AV Node
-autorhythmic

-atrial muscle AP's enter AV node by gap junction

-carry AP into ventricles, but there is a delay that allows the atria to pum blood (1/10 sec)
cardiac activation structures
-Ventricles
AV node activates Bundle of His at top of septum
cardiac activation structures
-Ventricles
-Bundle of His
-autorhythmic

-carries activation to Purkinje Fibers
cardiac activation structures
-Ventricles
-Purkinje Fibers
-autorhythmic

-nerve-like

-branch from apex(bottom) of heart upwards

-activate ventricular muscle upwards-pumps blood into aorta and pulmonary artery
cardiac activation structures
-Ventricles
-Ventricular Muscle
-gap junctions open, Na+ enters, open v-gated Na+ channels -> AP -> open v-gated Ca2+ channels allowing Ca2+ to enter -> Na+ and Ca2+ are closed, so K+ open and return the membrane potential to baseline
Pacemaker Cells
-autorhythmic

-no stable, baseline potential

-SA node, AV node, Bundle of His, and Purkinje fibers
Depolarization
-close K+ channels and open Ca2+ channels

-@ threshold-open many v-gated Ca2+ channgels

-Peak-Ca2+ channels close, K+ channels open and return below threshold
depolarization
-Neural Influences
SYMPATHETIC: -open more Ca2+ channels
-reach threshold sooner -> increase heartrate and get a stronger contraction

PARASYMPATHETIC: -decrease rate of K+ channel closing
-decrease rate of Ca2+ channels opening
-decrease heartrate
Electrocardiogram
sum of all AP's in heart
Electrocardiogram
-Relation To Cardiac AP
-1st derivative of sum of the electrical vectors

-leads detect electrical signal at different times
Electrocardiogram
-Relation To Cardiac AP
-P Wave
-QRS Complex
-T Wave
P wave-atrial depolarization

QRS complex-ventricular depolarization masking atrial repolarization

T wave- ventricular repolarization
-if EEG is mishapen-indicats myocardials inferact(tissue death)