Muscle tissue Flashcards
functions of muscle tissue:
movement, stability, storage/movement of substances within body, heat production
properties of muscle tissue:
- electrical excitability (chemical/ electrical stimuli)
- contractility (actin/ myosin sliding)
- extensibility (controlled stretching, protected by ct)
- elasticity (return to og size)
how does motion occur:
conversion of chemical energy (ATP) –> mechanical energy by contractile apparatus of muscle cells
contractile apparatus: made of
proteins actin and myosin
how does the 2 proteins create cellular contraction:
actin/ myosin form myofillaments, arranged parallel to direction of cell contraction
how do muscle cells respond to stimulus?
have excitable cell membrane, responds to stimulus = cellular contraction
muscle tissue term for: cytoplasm
sarcoplasm
muscle tissue term for: plasma membrane
sarcolemma, invaginated by (transverse) t tubules
- can pass action potentials
muscle tissue term for: sER
sarcoplasmic reticulum, stores and releases Calcium ions (key for action potentials)
list types of muscle tissueL
skeletal, cardiac, smooth
brief info/ contraction: skeletal
striated (striped), neatly arranged actin/ myosin
strong, quick discontinuous voluntary contraction
brief info/ contraction: cardiac
striated,
strong, quick continuous involuntary contraction
brief info/ contraction: smooth
not striated, irregular arrangement
weak, slow involuntary contraction
skeletal muscle features:
- very long tubular cells (myofibres/ muscle fibres)
- up of 30cm
- striated; cross striations
- voluntary: innervated (stimulated) by somatic nervous system
brief structure of muscle tissue:
muscle= many fascicles (muscle cell bundles)
surrounded by connective tissues: endomysium, perimysium, epimysium
define fascicle:
consists of myofibres
define myofibre:
consists of many myofibrils
define myofibrils:
bundles of myofilaments thick (myosin), thin (actin)
muscle tissue organisation: small to largest
myofilaments (proteins) -> myofibrils (organelles) -> myofibres (cells) -> muscle fascicle -> muscle
myofibre features: cross section/ structure/ glycogen
cross section: polygon shaped
- developed from myoblasts
- sarcoplasm (cytoplasm) surrounded by sarcolemma (plasma mem.) with 1-2 peripheral nuclei (just underneath sarcolemma)
- substantial glycogen