muscle contraction Flashcards
what is the function of myoepithelial cells
expel secretions from glandular acini
what are pericytes
smooth muscle like cells that surround blood cells
what are myofibroblasts
cells with a contractile role in addition to secreting collagen. important following tissue damage during the process of healing and repair, leading to the formation of a scar
what is atrophy
decrease in the size of an organ
what are myocytes
muscle cells
what does the sarcolemma do
make t tubules that project downward to the centre of the muscle fibre
what is the functional unit of myocytes
sarcomere
what is the sarcoplasm
the cytoplasm of a myocyte
what does the sarcoplasmic reticulum do
stores calcium and runs parallel to t tubules
what is found within the sarcoplasm
myofibrils that consist of contractile proteins and regulatory proteins
what do contractile proteins consist of
thick myosin and thin actin filaments
what is thick myosin
hundreds of myosin proteins
what are actin filaments
small globular proteins made from g actin
what is found on each g actin that forms the actin filaments
an active site that the myosin heads bind to during contraction
what do g actin form
a filament that looks like a long helix structure
what is f actin
the long helix structure formed by the combination of g actin
which proteins are found on f actin
troponin and tropomyosin
what are troponin and tropomyosin
regulatory proteins found on f actin
what is tropomyosin
string like protein that wraps around g actin and covers the active sites so the myosin heads cant bind
what is troponin
a protein with three subunits - t subunit, i subunit and c subunit. each one binds to something different
what does the t subunit of troponin bind to
tropomyosin
what does the i subunit of the troponin bind to
f actin
what does the c subunit of troponin bind to
calcium ions
what is the m line
the centre of the sarcomere