Muscles 1 Flashcards
What do muscles allow us to do?
Generate force and movement
Express and regulate ourselves
What are the two types of muscles?
Striated - skeletal and cardiac
Smooth - blood vessels, airways
Skeletal muscles are very ______. The form in ______ from ______ myoblasts and increase fibre size during growth.
Long, utero, mononucleate
How are the connective tissue muscles connected to bones?
By tendons
What proof is there that chains in the muscle fibres are very strong and compressed?
Nuclei found on the outside of cells.
Why are deeply penetrating blood vessels necessary?
Muscle fibres need a thick blood supply.
What are z-lines?
Border of the repeating unit.
What is another name for repeating unit?
Sarcomere
What is a guiding proteins function?
Ensures myosin can always slide in between 2 actin filaments.
Define actin.
Arranged in a double helix and each monomer is a binding site.
Define myosin.
2 actin binding sites on head, 2 ATP sites and a heavy chain and a light chain.
What is the process of the cross bridge cycle?
Cross bridges bind to actin Calcium concentration increases ADP and Pi break off of myosin Cross bridge has a conformational change ATP binds to myosin head Cause myosin to detach ATP hydrolyses Repeat
What does troponin, tropomyosin and calcium do in the cross bridge cycle?
Tropomyosin partially covers myosin binding site
Cooperative block with troponin
Calcium binds to troponin
Troponin alters shape, pulling tropomyosin away
Removal of calcium will reblock the myosin sites
Where is calcium stored?
Sarcoplasmic reticulum.
Define motor unit.
Motor neurones and muscle fibres.
