intro to muscles Flashcards
1
Q
what are the different types of muscle
A
1) skeletal [striated]
2) cardiac muscle [striated]
3) smooth muscle [non-striated]
2
Q
what are muscles made of
A
muscle fibre: skeletal muscle cell- endomysium.
fascicle- clusters of muscle fibres- perimysium
multiple fascicles- epimysium
3
Q
actin
A
thin filaments
anchored to Z line
4
Q
myosin
A
thick filaments
anchored to the M line
5
Q
filament structure
A
6 thin filaments surround each thick filament
6
Q
contraction
A
myosin molecules rapidly bind and release to actib and ‘walk’ along actin filameny
7
Q
T- tubular system- muscle contraction
A
- nerve signal
- excitation f muscle cell membrane
- message conveyed by T-tubular system
- calcium released from terminal cisternae into sarcoplasm
- initiates muscle contraction
8
Q
cardiac muscle
A
- central nuclei
cellular connections:
development differs to skeletal muscle.
intercalated discs-> communicating gap junctions
9
Q
smooth muscle
A
location- follow viscera and blood vessels
- spindle shapes
- variable size
- central nucleus
- longitudinal: lineal bundles
- cross section- polygonal profiles
- external lamina surrounds cells
contraction:
- very different to striated muscle
- no myofilaments
- contractile proteins crisscross- anchored at focal densities
- cell elongated when relaxed
- globular shape during contraction
