The Heart Flashcards
What makes up the looser connective tissue layer of the endocardium?
Fibroelastic connective tissue
What types of tissues and fibers make up the dense irregular connective tissue layer of the endocardium?
More collagen I and elastic fibers and some smooth muscles (for support not contraction)
What is a term used to describe the looser connective tissue layer and dense irregular layers of the endocardium?
Sub-endothelium connective tissue layer
What makes up the sub-endocardial layer of the endocardium?
Looser connective tissue with blood vessels, nerves
Where are the Purkinje fibers located in the endocardium?
Within the sub-endocardium
What are Purkinje fibers?
Modified cardiac myocytes
What substance is stored in the Purkinje fibers?
Glycogen
How are Purkinje fibers attached?
Gap junctions and desmosomes
What is the function of the Purkinje fibers?
To conduct contraction impulse rapidly
What chambers of the heart have less muscle and more elastic fibers?
Atria
What chambers of the heart have well-developed cardiac muscle layer?
Ventricles
What portion of the intercalated discs are the risers of the stairs?
Transverse
What portion of the intercalated discs are the steps of the stairs?
Longitudinal portion
What cell junctions make up the transverse portion of the intercalated discs?
Macula adherens and fascia adherens
What portion of the intercalated discs have large gap junctions which enable the flow of ions for contraction?
Longitudinal portion
What is the function of the macula adherens in the transverse portion of the intercalated discs?
Attach cardiomyocytes in a row
What is the function of fascia adherens in the transverse portion of the intercalated discs?
Attach and stabilize myofibrils
What are the three functions of the intercalated discs?
Arrange cardiac myocytes in a row, attach and stabilize myofibrils, cell to cell communication/transfer of ions