Flashcards in Cardiac Muscle Tissue - Downing Deck (8)
General Features of Cardiac Muscle:
T-tubule system (at z lines, not AI junctions)
Sarcoplasmic reticulum less well developed than in skeletal muscle
Single nucleus/cell; centrally located
Intercalated disks are diagnostic features of cardiac muscle tissue
If things look messy.... its cardiac muscle!
What is the comparison in number of mitochondria between cardiac and normal skeletal muscle?
Cardiac has TON of mitochondria!
Where do you normally find intercalated discs?
They can be located in spots where you would normally see the Z-disc
What parts of the intercalated discs do you see the macula adherens(desmosomes), zonula adherens, and gap junctions????
In the vertical portion:
What is microscopic feature unique to atrial cadriac muscle cells?
Contain atrial natriuretic peptide
Lowers blood pressure by decreasing renal tubules ability to resorb (conserve) sodium and water
What are the modified cardiac muscle cells in the conduction system of the heart called?
Myofibrils reduced in number
Contain more sarcoplasm
Nuclei more rounded
Referring to their development, why do cardiac muscles have a single nucleus rather than many like in skeletal muscle?
Myoblasts DO NOT fuse in cardiac muscle