ch 10 - lecture review Flashcards
epimysium
layer of collagen fibers that surrounds entire muscle and separates it from surrounding to tissues
perimysium
surrounds fascicles
endomysium
surrounds individual muscle cells
what is the organization of a muscle tissue
Myofilament
Myofibril
Muscle fiber
Fasicle
Muscle tissue
myofilament
bundles of contractile protein filaments
myofibril
collections of myofilaments that are responsible for muscle contraction
muscle fiber
muscle cell
fascicle
bundle of muscle fiber
muscle tissue
2 types of myofilament
actin (thin) and myosin (thick)
sarcolemma
plasma membrane of a muscle fiber
sarcoplasm
cytoplasm of a muscle fiber
transverse tubules (t-tubules)
narrow tubes continuous with the sarcolemma, which extend from the surface of the muscle fiber deep into the sarcoplasm
sarcomere
repeating structural and functional units of a myofibril
sarcoplasmic reticulum
tubular network similar to smooth ER that surrounds each myofibril and forms terminal cisternae
terminal cisternae
store calcium and attach to T tubules
triad
2 cisternae plus a T tubule
A bands
dark bands, which run the length of the thick filaments
subdivisions of A band
M line
H band
zone of overlap
M line
vertical line in center of A band; contains proteins that stabilize the position of the thick filaments
H band
made only of thick filaments and extends on either side of the M line
I band
light bands that contain only thin filaments
which segments in a sarcomere, shorten during contraction?
H and I bands
the 4 different types of protein that make up a myofibril.
Actin
Myosin
Tropomyosin
troponin
Which protein does the myosin head bind to during contraction?
actin
which ion helps in contraction process
calcium
sliding filament theory
during a contraction, thin filaments slide toward the center of the sarcomere (M line) alongside the thick filaments
Excitation- Contraction coupling?
the link between the generation of an action potential in the sarcolemma and the start of muscle contraction
neuromuscular junction
the synapse between a motor neuron and a skeletal muscle fiber
parts of nmj
axon terminal: expanded end of the axons of the motor neuron
motor end plate: folded membrane of the skeletal muscle fiber at the NMJ
synaptic cleft: space between the axon terminal and motor end plate
motor unit
a motor neuron and all the muscle fibers it controls
thin filament contain
- filamentous actin (f-actin)
- nebulin
- tropomyosin
- troponin
filamentous actin (f-actin)
twisted strand composed of 2 rows of G-actin molecules
active sites on G-actin bind to
myosin
nebulin
holds the F actin strands together
tropomyosin
covers the active sites on G-actin and prevents actin-myosin interaction
troponin
globular protein that holds tropomyosin in place and binds to calcium ions
contraction steps (6)
- brain stimulates muscle contraction + releases action potential
- terminal cisternae releases Ca to bind to troponin
- troponin becomes flat when Ca binds
- tropomyosin slips off which exposes active sites on G-actin
- myosin heads binds to exposed active sites
- power stroke/musclencontracts
Tendon
Bone to muscle
aponeurosis
blending of epi, peri, and endomysium that forms a broad sheet at the end of a muscle
thin filament consists of
pair of F actin molecules twisted together
