Please enable JavaScript.
Coggle requires JavaScript to display documents.
CV: Heart (Anatomy (controlled by conduction system (SA node (located…
CV: Heart
Anatomy
located within the thoracic cavity
in mediastinum then more internally in pericardial cavity
composed of 3 muscular layers
epicardium
outermost heart layer
composed of simple squamos epithelium
AKA visceral layer of serous pericardium
myocardium
thickest layer of heart
composed of cardiac muscle tissue
endocardium
composed of simple squamos epithelium
continuous with lining of valves
controlled by conduction system
Purkinje fibers
extend from AV bundle into L & R ventricles
AV bundle
extends from AV node
AV node
in the floor of R atrium between R AV valve and coronary sinus
SA node
located posterior wall of R atrium
"pacemaker" of heart initiates heart beat
separated in 4 chambers
L & R ventricle and atria
valves separate atria from ventricle
L & R AV valve
valves suspended by chordae tendinae
controlled by papillary muscles
valves allowing flow from ventricles out of heart
Pulmonary semilunar valve
flow from R ventricle to pulmonary trunk
aortic semilunar valve
flow from L ventricle to Aorta
Cardiac Cycle
Late Ventricular systole
atria relax while ventricles keep contraction
semilunar valves open allowing flow into aorta and pulmonary trunk
AV valves remain closed
Early Ventricular diastole
atria & ventricles relax
all valves closed
filling of atria
Early Ventricular systole
atria relax while ventricles contract
AV valves close, semilunar remain closed
Late Ventricular diastole
atria & ventricles relax
AV valves open to fill ventricles
semilunar valves close
begin cycle once again
Atrial systole
both Atria contract causing flow into ventricles
AV valves open while semilunar valves remain closed
Electrocardiogram
records electrical activity of the heart
composed of waves and segments
P wave
electrical changes of atrial depolarization
T wave
electrical charge associated with ventricular repolarization
one complex
QRS complex
electrical changes associated with ventricular depolarization
two intervals
P-R Interval
time from beginning of P wave to beginning of QRS deflection
Q-T Interval
time from beginning of QRS to end of T wave
Electrical & Mechanical events of Cardiac cells
Plateau
slow CA2+ channels open; CA2+ enters cell
entry of CA2+ initiates mechanical contraction
CA2+ ions bind to troponin beign cross-bridging with sarcomere
entrance of CA2+ triggers more release of CA2+ from SR
simultaneous entrance of CA2+ and release of K+ causes no electrical change
depolarization triggers opening of K+ channels; K+ leaves cell
Repolarization
CA+ channels close; K+ channels remain open
decrease in CA+ levels in cell
CA2+ releaesed from troponin; decrease in cross-bridges of tick and thin filaments; return to resting length
resting membrane potential reestablished
Depolarization
AP transmits opening of NA+ channels
NA+ ions flood cell causing depolarization
voltage gated channels close to inactive state