Smooth And Cardiac Muscle Tissue Flashcards
What are intercalated discs?
The join 2 cardiocytes together.
What are the components of the intercalated discs?
Macula adherentes (desmosomes)- link the desmin of the adjoins cardiac muscle cells. Transverse component.
Fascia adherentes- transverse component anchors the actin filaments of the sarcomeres
Gap junctions- longitudinal component allows cell communication.
What are atrial natriuretic peptides (ANP)?
Secreted by cardiac muscle cells in the atria.
Promote dilation of blood vessels and low BP. Regulates fluid electrolyte balance. Stimulated by atrial stretch.
Smooth muscle doesn’t contain sarcomeres, how are actin and myosin arranged and what are dense bodies?
They’re arranged in a meshwork fashion. Dense bodies anchor actin filaments to the cell membrane and report force of contraction to cytoskeleton and cell membrane.
How does smooth muscle get its calcium if it has no T-tubules?
Extracellular calcium via pinocytotic vesicles.
What are calveolae and lipid rafts in smooth muscle?
Together they work on transportation via vesicles.
What chemicals are used in smooth muscle innervation?
Adenergnic- epinephrine and norepinephrine and muscarinic-acetylcholine
Nicotinic cholinergenic- ACTH
Via gap junctions
How is the T-tubule system different in cardiac and skeletal muscle tissue?
Cardiac T-tubules are less extensive and form a diad instead of a triad and they’re located further away at the Z lines compared to skeletal muscle.
