Muscle Structure Flashcards
What is a myofibril?
a structure made of fused cells that share nuclei and sarcoplasm
What are the myofibrils made up of?
sarcomeres
What are muscle fibres made up of?
many myofibrils that collectively bring about force to cause movement
What 2 types of proteins make up sarcomeres?
myosin and actin
What is the thick filament made up of?
myosin
What is tropomyosin and where is it located?
a protein found wrapped around actin
What is the A-band?
the total width of the myosin, bands are dark due to both action and myosin
What is the H-zone?
the area made up of ONLY myosin
What is the I-band?
where there is actin ONLY
What is the M-line?
middle of the myosin
What is the Z-line?
the line showing the start/end of the sarcomere
What is the general structure of slow-twitch fibres?
- contain large amounts of myoglobin (storage of oxygen)
- a rich blood supply (deliver oxygen and glucose for respiration)
- many mitochondria (to produce ATP in aerobic respiration)
What is the general structure of fast-twitch fibres?
- more myosin
- large store of glycogen
- store of phosphocreatine
- large amount of enzymes needed in anaerobic respiration
What is myoglobin?
a protein that can store oxygen
What are the general properties of slow-twitch fibres?
contract slower and respire aerobically for longer periods, adapted for endurance work
