Lecture 22: Heart Gross Anatomy Flashcards
what is another term for anterior IV branch
LAD (left anterior descending)
what do cardiac veins accomplish
remove metabolic products from myocardium
what do coronary arteries do
supply myocardium with oxygen
what do arteries end in
arterioles then capillaries
what is the basis of collateral circulation
anastemoses
if an artery doesnt have an anastemosis what is it called
end artery
what happens with occlusion of an end artery
necrosis of the tissue being supplied
classic example of an end artery
central artery of the retina
what happens with coronary occlusion
myocardial infarction (necrosis) and heart attack
what happens with coronary insufficiency
myocardial ischemia and angina pectoris (cardiac/chest pain)
3 most common areas of cardiac occlusion
RCA, LAD, circumflex
what kind of gland is the heart
endocrine
what kind of cells is the myocardium composed of
cardiac muscle cells (myocytes or cardiocytes), contractile cells, myoendocrine cells (atrial myocytes), conducting cells
conducting cells of the heart
nodal cells, bundle branches, purjinke fibers
how do cardiac muscle fibers in myocardium run
opposite directions, spirally around atria and ventricles
complex spiral arrangements of ventricles explanation on a cellular level
Cardiac myocytes are separated by perimysium into
bundles/fascicles of various sizes with different
orientations
how does ventricle contract (physical description)
like wringing of a towel
length of cardiac myocytes
long lived
what do cardiac myocytes accumulate in old age
lipofuscin pigment (yellow/brown, wear and tear)
can cardiac myocytes regenerate
no
describe the ECM of the heart
1) basal lamina form weave surrounding cardiocytes
2) elastic fiber bundles wrap around cardiocytes
3) collagen fibrils insert onto basal lamina
4) collagen fiber bundles form collage struts between neighboring cardiocytes
atrial vs ventricular myocytes
smaller in size
fewer transverse tubules
have granules
why is heart an endocrine organ
atrial myocytes synthesizes atrial natriuretic peptide (ANP) and store it in granules
when is ANP released
in response to stretch of atrial wall - secreted by exocytosis into blood circulation
what does ANP do
blocks sodium reabsorption in renal tubules thereby promoting sodium and urine excretion
what is the atrioventricular bundle called and composed of
bundle of his
L and R ventricular bundle
where are purjinke fibers
sub endocardium
