Week 11 Flashcards
Define Epimysium
- Surrounds the entire muscle and then blends into the intramuscular tissue sheaths to form tendons
Define perimysium
Surrounds a bundle of fibres called a fasciculus
Define endomysium
Wraps each muscle fibre and separates it from neighboring fibers
Define sarcoplasm
- Contains the nuclei that contain the genes, mitochondria and other specialised organelles
Define sarcolemma
- Surrounds each muscle fibre and enclose the fibres cellular contents
Define muscle origin
- When the tendon is attached to the bone
Define insertion point
- Where the muscle is attached to the moving bone
Define Capiliarisation
The formation and development of a network of capillaries to a part of the body
What is the difference in total number of capillaries per area of muscle in endurance trained athletes to normal people
40
Myofibril contain what two things
Actin and myosin
What determines a muscles functional propertied
Sarcomere length
Define sliding filament model
Proposes that muscle shortens or lengthens because the thick and thin filaments slide past each other without changing length
myosin cross bridges attach to what
Actin filaments
Define cross bridge cycling
The molecular mechanism whereby myosin and acting myofilaments slide over each other is termed the cross-bridge cycle
Define excitation contraction coupling
describes the rapid communication between electrical events occurring in the plasma membrane of skeletal muscle fibres and Ca2+ release from the SR, which leads to contraction.
Deactivation serves what two purposes
- Prevents any mechanical link between myosin cross bridges and actin filaments
Inhibits myosin ATPase activity to curtail ATP splitting
When does relaxation occur
When actin and myosin return to their original state
Differences in sarcomere alignment and length affect what
Muscle force and power
two muscle fibre alignment types
Pennate
Fusiform
3 ways pennate muscles differ from fusiform fibers
- They generally contain shorter fibers
- They possess more individual fibers
- They exhibit less range of motion
What way do fusiform muscle fibers run
Parallel to the muscles long axis
What encases skeletal muscle
Connective Tissue
Muscle fibre consists of 75% X
25% Y
5% z
X - water
Y - Protein
Z - salts/other
What represents a functional unit of a muscle fiber
Sarcomere
What activates actin and causes myosin crossbirdges to attach
Calcium