Cardiac Histology

Question 1

What are the two parts of the transverse region of the intercalated disc?

Answer 1

Fascia adherens: actin filaments, transmit contractile forces between cells (most numerous)

Desmosomes: anchor intermediate filaments to the cytoskeleton

Question 2

In what layer are the coronary vessels found?

Answer 2

In the epicardial fat

Question 3

What are lipofuscin granules?

Answer 3

Small bodies of materials digested by lysosomal function. They accumulate near the nuclei as a part of aging.

Question 4

What helps smooth muscle cells contract uniformly?

Answer 4

Gap junctions

Question 5

Where are the T Tubules in the myocardium located?

Answer 5

On top of the Z discs

Question 6

What is released by myoendocrine cells?

What is its function?

Answer 6

Atrial natriuretic factor.

Tells the kidney to increase the glomeriolar filtration rate.

Increases excretion of Na and Water (to lower blood volume)

Question 7

What anchors the contractile apparatuses of smooth muscle to the cell wall?

Answer 7

Dense bodies

Question 8

What two structures sit on top of Z discs?

Answer 8

T Tubules

Intercalated disks

Question 9

What do we find in the longitudinal region of the intercalated disc?

Answer 9

Gap junctions

allows excitation to pass between cells

Question 10

What is the epicardium made of?

Answer 10

Fibrocollagenous connective tissue with a mesothelium lining.

Question 11

What are dense bodies made of?

Answer 11

Desmin and vimentin

Question 12

What type of cardiac myocyte lacks T tubules and has less than normal intercalated discs?

Answer 12

Cardiac myocytes of the purkinje fibers

Question 13

What is the special name for the T Tubules of smooth muscle?

Answer 13

Caveolae

Question 14

What is the endocardium made of?

Answer 14

Endothelium and a thin layer of loose CT

Question 15

What is the tissue type of the epicardium?

Answer 15

dense fibrocartillagenous CT with elastic fibers, lined with mesothelium

branches of the coronary arteries are embedded with the surrounding adipose

Question 16

What are the Hallmark Features of the Myocardium?

Answer 16

Diad T tubule system

striations, intercalated discs, lipofuscin granules

Question 17

Z discs can be found at sites where __ meet end to end and function to do what?

Answer 17

cells

bind cells, transmit forces of contraction and allow the spread of excitation

Question 18

What are Diad T-Tubules?

Answer 18

1 T tubule and 1 SR cisterna

found at z lines

permits uniform contraction of myofibrils within a single cardiocyte

Question 19

What are nodal cardiocytes?

Answer 19

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

Question 20

Purkinje Fibers (subendocardial branches)

Answer 20

conduct electrical impulses that allow coordinated contraction

less myofibrils, lots of glycogen

mostly lack T tubules

Question 21

Ventricles:

What is the subendocardial layer?

Atria:

What is the subendocardial layer?

Answer 21

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

Question 22

What is the tissue type of the cardiac skeleton?

What is the function of the cardiac skeleton?

Answer 22

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

Question 23

What is the tissue type of Heart Valves?

Answer 23

Core of fibroelastic CT covered by endothelium continuous with cardiac skeelton

know the image (HY according to tuturs)