Flashcards in 5.1 Skeletal muscle Deck (39):
what is each muscle composed of?
what is the connective tissue called that bundles fibres together?
what are the smaller fibres in muscles called?
what do myofibrils contain?
2 types of protein
myosin and actin
muscles are made of...
fascicles are made of...
muscle fibres are made of...
myofibrils are broken down into...
sarcomeres are made of...
thin & thick filaments (actin and myosin)
what are the I bands and why?
light - actin and myosin don't overlap
only actin there
what is the A band and why?
appear darkest where actin and myosin overlap
darkness due to presence of thick myosin filaments
where is the Z line found?
at the centre of each light band
what is the distance between the two z lines?
what happens to the sarcomere when muscle contracts?
it shortens, z bands move closer and I bands nearly disappear
what is the H zone?
a lighter coloured region in the centre of the dark band
what is in the H zone?
only myosin filaments
what are the two different types of muscle fibres in skeletal muscle?
slow twitch and fast twitch
do slow twitch fibres contract slowly or quickly?
are slow twitch fibres more or less powerful over time?
what are slow twitch fibres used for?
do slow twitch fibres tire easily?
where is slow twitch fibres energy gained from?
what are slow twitch fibres rich in?
myoglobin, blood vessels and mitochondria
Where are slow twitch fibres found in large proportion?
Muscles that maintain posture e.g. Back and calf muscles
Do fast twitch fibres contract quick or slow?
Do fast twitch fibres give powerful contractions?
Yes for short periods
What are fast twitch fibres used for?
Short birds of speed and power
Do fast twitch fibres tire easily?
Where do fast twitch fibres gain energy from?
What colour are fast twitch fibres?
What are fast twitch fibres low in?
Levels of myoglobin and blood vessels
What do fast twitch fibres have more of?
More thick myosin filaments
What do fast twitch fibres store?
What does creatine phosphate do?
Rapidly generates ATP from ADP in anaerobic conditions
Where are fast twitch fibres found in high proportions?
In muscles that need short bursts of energy such as biceps and eyes
What are myofibrils?
Long cylindrical organelles
Made of actin and myosin
Specialised for contraction
Lined up parallel to provide maximum force
What is actin?
Filament consisting of two strands twisted around each other
What is myosin?
The thick filament consisting of rod shaped fibres with bulbous heads that project to one side