Muscle 1 Flashcards
What are the 2 types of Muscle?
Smooth and striated
What two subtypes make up striated muscle?
Skeletal (voluntary muscle and diaphragm)
Cardiac
What does smooth muscle make up?
Blood vessels, airways, uterus etc
What makes up each skeletal muscle fibre?
Each fibre is a large multinucleic cell packed with protein pushing the nulcei to the edge
How do skeletal muscle fibres form?
In Utero from mononucleate myoblasts
What encases the bundles of fibres that make muscles?
A connective tissue sheath
What connects muslce tbone?
Tendons
What cells replace injured skeletal muscle cells?
Satellite Cells
Why cant muscles fully recover from injury and what is done to compensate?
Theres a limited supply of satellite cells
Other fibres undergo hypertrophy to compensate for the damaged fibres.
What is a myofibril?
Every muscle fibre is packed with protein in the form of myofibrils that are like lon chains of myosin and actin filaments.
What is the sarcomere?
The sarcomere is the repeating unit of the myofibril
How are actin and myosin filaments arranged in the myofibrils?
The thick myosin filaments are arranged in triangles and the thin actin filaments in hexagons. This way every myosin filament is evenly surrounded by 6 actin filaments.
What binds myosin and actin filaments together?
Cross bridges on the myosin fliament
What happens to the filaments when muscle contracts?
The cross bridges drag the actin filament along, sliding the two filament types along eachother.
What binds to myosin cross-bridges?
They have actin binding sites and ATP binding sites.