Muscles Flashcards
Types of muscles
Smooth
Cardiac
Skeletal
which muscles are striated
cardiac
skeletal
how is skeletal muscle attached to bone
via tendons
features in skeletal muscle
cell membrane
myofibril
sarcoplasm
myofilaments
what is within myofibrils
lots of myofilaments
what is within myofilaments
actin and myosin
what are the units in myofilaments
sarcomeres
is actin thick or thin
thin
is myosin thick or thin
thick
what is the dark band
A band
what the light band
I band
what line is myosin attached to
M line
what is actin anchored to
Z discs
sliding filament theory
- Ca2+ are released from the SER into the sarcoplasm
- Ca2+ diffuse and bind to troponin
- causing a conformational change to the tertiary structure
- causing tropomyosin to move away exposing the myosin head binding sites on actin
- myosin heads bind to actin bindings dorming cross bridges
- myosin heads bend pulling the actin filament (power stroke)
- ADP + Pi are released from myosin head
- new ATP binds to myosin heads
9a. breaks cross bridges and separates it from actin
9b. ATP hydrolysis to ADP and Pi (recovery stroke) - process repeats pulling the actin along
what is ATP required for
sliding of filaments during contraction
the active transport of calcium to the SER
role of Ca2+ ion
Ca2+ ions are actively transported back into Sarcoplasmic ER
Ca2+ ions also activate ATP Hydrolase
describe the role of phosphocreatine
provide phosphate
to synthesis ATP
how do slow twitch fibres work
produce slow sustained contractions over long time periods but have a slower rate of contractions
eg. calves
how do fast twitch fibres work
produce rapid strong contractions as have a faster speed of contractions but only sustained over a short period of time
muscles which contain this fibre are fast to fatigue due to a buildup of lactate
properties of slow twitch fibres
darker in colour
more mitochondria
more capillaries
less glycogen
less phosphocreatine
less sarcoplasmic ER
less calcium ions
slow sustained contractions
less force
slow fatigue
aerobic respiration
properties of fast twitch fibres
more pale
more glycogen
more phosphocreatine
more sarcoplasmic ER
more calcium ions
rapid strong contractions
more force
fast fatigue
anaerobic respiration
People who have McArdle’s disease produce less ATP than healthy people. As a result, they are not able to maintain strong muscle contraction during exercise. Use your knowledge of the sliding filament theory to explain why
(Idea ATP is needed for:) 1. Attachment/cross bridges between actin and myosin; 2. ‘Power stroke’ / movement of myosin heads / pulling of actin; 3. Detachment of myosin heads; 4. Myosin heads move back/to original position / ‘recovery stroke’;
