Muscle Structure and Function Flashcards
muscle tissue
consist of muscle cells (fibres)
all muscle characteristics
excitability
contractibility
extensibility
elasticity
3 major muscle types
smooth
cardiac
skeletal
smooth muscle
has spindle-shaped non-striated uninucleated fibres
occurs in walls of internal organs
vessel, digestive tract
-is involuntary
Muscle types differentiated by
fibre shape
location of nuclei
appearance - striated, smooth
nature of control- voluntary or involuntary- hybrid
cardiac muscle
has striated, branched, uninucleated fibres
occurs in walls of heart
is voluntary
skeletal muscle
has striated, tubular, multinucleate fibres
is usually attached to skeleton
is voluntary
Epimysium
surrounds all the muscle fibre bundles (fasciculi) to form the entire muscle
Perimysium
surrounds several muscle fibres and forms bindles called fasciculi
Fassiculus
bundle of up to 150 muscle fibres
endomysium
wraps each muscle fibre
by weight, a single muscle fibre is made up of primarily
water
single muscle fibre (cell, weight consists of)
75% water
20% protein
5% other
-minerals (K+, Na+, CI-) fats, CHO, amino acids, enzymes, ATP, lactate ect.
Microstructure of muscle: sarcolemma
muscle cell membrane surrounding muscle fibre
Microstructure of muscle: satellite cells
located within the sarcolemma (between the plasma and basement and membrane)
-help regenerative cell growth (myogenic stem cells)
-play a role in hypertrophy
Microstructure of muscle: sarcoplasm
protoplasm (enzymes, fat, glycogen)
nuclei
sarcoplasmic reticulum (SR)
network of tubules and vesicles (triads)
located around myofibrils
provides structural integrity and spreads depolarization
role: stores, releases and reabsorbs Ca2+
each sarcomere contains ____ triads
two
triad system
2 large sacs (vesicles)
-terminal cistern of the SR
small central sac
-T tubule
Muscle microstructure
within the single muscle fibre there are myofibrils
-myofibrils =1/1000mm in diameter
up to 8000 myofibrils
myofibrils contain myofilaments
Myofilaments are _______ that make up sarcomere units
proteins
myofilaments
-functional unit of muscle fibre
-runs from z-line to z-line
order from whole muscle
-myofilament
-myofibril
-muscle fibre
-muscle fasiculi
whole muscle
muscle fasiculi
muscle fiber
myofibril
myofilament
at what level would we find a bundle of muscle fibres?
fascicle