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cardiac muscle vs. Skeletal?
- cardiac- smaller in size, single-centered nucleus,
- skeletal-do not branch between cells, do not have intercalated discs.
when is first heart sound heard?
AV valve closes
when blood comes back to heart after going to lungs what structure does it go to first?
what happens during isovolumetric phase of ventricule systole?
Atrioventricular valve and semilunar valve closed
expandable extension of atrium
what happens if damage to chordae tendinae?
- 1- mitral regurgitation
- 2- mitral valve prolapse
- 3- bicuspid regurgitaton
- 4- bicuspid prolapse
when semilunar valve close what happens to AV valve?
coronary sulcus location?
marks border between atria and ventricle
what happens during cardiac cycle?
QRS complex of ECG precede the increase in ventricular pressure
what structure deliver blood to myocardium?
right and left coronary artery
location of pecinate muscle
muscle ridges run along surface of auricles
first vessel to branch from aorta?
volume of blood ejected from each ventricle during contraction
blood supplied to L atrium via?
L coronary artery
chordae tendineae do what?
attach papillary muscle to cusps of atrioventricular valve
first sign of coronary artery disease?
what branches are part of R coronary artery?
- marginal branch
- posterior interventricular branch
what increase cardiac output?
- incrase venous return
- incrase sympathetic stimulation
- increase heart rate
how long heart beat last?
what do contractions of papillary muscle do?
prevent AV valve from reverse into atria
size of cells in conducting sytem and contain how many myofibrils?
most of cells in conducting system are smaller then contractile cells of myocardium and contain few myofibrils
branches of L coronary artery?
- circumflex branch
- anterior descending artery
What is SA node known as?
cardiac pacemaker /natural pacemaker
Starlings law of heart re: cardiac output?
directly related to venous return
another name for visceral pericardium?
if action potential initated in AV node how many heart beats per minute?
where do great and middle cardiac veins drain?
into coronary sinus
what increase heart rate?
- -sympathetic stimulation of nodal fibers
- -incrase levels of epinephrin in flud around heart
- -increase permeability of myhocardial membrane to sodium
- -activation of cAMP in heart muscle
function of pericardium?
anchor heart to surrounding structures
depolarization of atria
what structure permit blood flow from R to L atrium while lungs develop before birth?
what happens when increased blood to R atrium?
- cause SA node to depolarize faster
- increase HR
- trigger atrial reflex (bainbridge)
why cant tetanic muscle contract in normal cardiac muscle cell?
refractory period lasts until muscle cell relaxes.
what circuit does L ventricle pump blood?
what makes amt of force that blood comes out of heart?
- degree of stretching at end of ventricle diastole
- contractile of ventricle
- amt of pressure required to eject blood
depolarization phase of action potential is result of what?
incrase membrane permeability to sodium
intercalated disk is what?
two cardiac muscle cells connected by gap junction
ventricle systole what happens?
AV valves close
plateu phase is due to what?
calcium channel remain open longer then sodium channel
how many times heart beat daily?
wha happens to ventricle chamber when L ventricle contracts ?
where do calcium ions come from for contraction?
liters of blood pumped daily?
what happens as result of long refractory period ?
calcium channel blockers do what?
decrease force of heart contracation
enzymes found in blod following MI?
order of conduction system?
- sa node
- av node
- av bundle
- bundle branches
- purkinje fibers
clot form on plaque of coronary vessel and blocks blood flow