Cardiac Histology Flashcards
What are the two parts of the transverse region of the intercalated disc?
Fascia adherens: actin filaments, transmit contractile forces between cells (most numerous)
Desmosomes: anchor intermediate filaments to the cytoskeleton
In what layer are the coronary vessels found?
In the epicardial fat
What are lipofuscin granules?
Small bodies of materials digested by lysosomal function. They accumulate near the nuclei as a part of aging.
What helps smooth muscle cells contract uniformly?
Gap junctions
Where are the T Tubules in the myocardium located?
On top of the Z discs
What is released by myoendocrine cells?
What is its function?
Atrial natriuretic factor.
Tells the kidney to increase the glomeriolar filtration rate.
Increases excretion of Na and Water (to lower blood volume)
What anchors the contractile apparatuses of smooth muscle to the cell wall?
Dense bodies
What two structures sit on top of Z discs?
T Tubules
Intercalated disks
What do we find in the longitudinal region of the intercalated disc?
Gap junctions
allows excitation to pass between cells
What is the epicardium made of?
Fibrocollagenous connective tissue with a mesothelium lining.
What are dense bodies made of?
Desmin and vimentin
What type of cardiac myocyte lacks T tubules and has less than normal intercalated discs?
Cardiac myocytes of the purkinje fibers
What is the special name for the T Tubules of smooth muscle?
Caveolae
What is the endocardium made of?
Endothelium and a thin layer of loose CT
What is the tissue type of the epicardium?
dense fibrocartillagenous CT with elastic fibers, lined with mesothelium
branches of the coronary arteries are embedded with the surrounding adipose
What are the Hallmark Features of the Myocardium?
Diad T tubule system
striations, intercalated discs, lipofuscin granules
Z discs can be found at sites where __ meet end to end and function to do what?
cells
bind cells, transmit forces of contraction and allow the spread of excitation
What are Diad T-Tubules?
1 T tubule and 1 SR cisterna
found at z lines
permits uniform contraction of myofibrils within a single cardiocyte
What are nodal cardiocytes?
modified cells within the SA/AV nodes that initiate/relay electrical signals
only modify the rate of intrinsic cardiac muscle contraction
SA node-AV node-AV buncle-R/LBB-purkinje fibers
Purkinje Fibers (subendocardial branches)
conduct electrical impulses that allow coordinated contraction
less myofibrils, lots of glycogen
mostly lack T tubules
Ventricles:
What is the subendocardial layer?
Atria:
What is the subendocardial layer?
thin layer of CT with smooth muscle in the ventricle that merges with the myocardium
contains subendocardial branches
lacking. Purkinje fibers are closer to endoethlium with mixed myocardium
What is the tissue type of the cardiac skeleton?
What is the function of the cardiac skeleton?
dense irregular CT in endocardium
anchors valves, surrounds AV canals to mantain shape, contributes to interventricular and interatrial septa, extends into the valves and Chordae Tendondae for insertion of muscle and insulates atria/ventricles
What is the tissue type of Heart Valves?
Core of fibroelastic CT covered by endothelium continuous with cardiac skeelton
know the image (HY according to tuturs)
