Muscle structure Flashcards
Based on Yeo lectures. Basics of muscular structure
What are the three types of muscle?
Smooth, cardiac, skeletal
What is the definition of contraction?
The active state of muscle generating tension
What are the three types of contraction?
Isometric (no length change), concentric (shortening), and eccentric (lengthening)
What is the definition of tension?
A pulling force exerted by each end of muscle
What is the hierarchy of muscle?
Actin + myosin filaments Sarcomeres Myofibril Fibers Fascicles Muscle Compartments
Outline the sliding filament theory
A.p. along sarcolemma Down t-tubules To SR Ca2+ released Bind to troponin Tropomyosin moved aside Myosin head binds to actin (cross-bridges) Myosin head moves backwards • - ADP + Pi released Actin filament pulled past myosin ATP to myosin head Cross-bridges hydrolysed • - ATP --> ADP + Pi Myosin head moves to original position
What are fibers covered in?
Endomysium, which carries capillaries and the nerves that innervate each fiber
What are fasicles covered in?
Peromysium, which protects muscle fibres and provides pathways for nerves and blood vessels
What are muscles covered in?
Epimysium, which transfers tensions to the tendon
What are compartments separated by?
Fascia, which is a sheet of fibrous tissue
How is force transferred?
The contractile fibres generate tension, applying force to both ends. This force is gathered in tension and the resultant force pulls bone, transferring force from fibre to bone
What is the name of the point at which tendon connects to muscle?
Musculo-tendinous junction
What is the name of the point at which tendon connects to bone?
Teno-osseous junction
What is the composition of tendons?
Consist of collagen fibres arranged parallel to force application of muscle
What is an aponeurosis?
A sheet of fibrous tissue taking the place of a tendon in sheet-like muscles with a wide area of attachment