Muslces Flashcards
What’s sarcoplasm
Cytoplasm of muscle fibres
What’s sarcolemma
Cell membrane of muscle fibres
What are T - tubules
Sarcolemma folded inwards. Conductive. Carry electrical impulse throughout sarcoplasm
What’s the sarcoplasmic reticulum
network of sac-like membranes that is found in the sarcoplasm.
○ Its structure is very similar to the endoplasmic reticulum.
○ The sarcoplasmic reticulum stores calcium ions (Ca2+); these are important for muscle contraction.
What does it mean if skeletal muscle fibres are multinucleate?
Each cell may contain several nuclei and are also rich in mitochondria for atp production
What proteins are myofibrils composed of?
Myofilaments
What is myosin
Protein, dark band,called A-band
What is actin
Protein, light band, called I- band
What are sarcomeres
Smallest functional unit of skeletal muscle. End is called Z-line and middle is called M-line
What is the sliding filament theory
Actin and myosin filament slide over one
another to contract and shorten the
sarcomere.
Sliding filament theory: muscle contradiction
The I-band (composed of actin) gets
shorter.
The H-zone (composed of myosin) gets
shorter.
The A-band (a mixture of actin and myosin)
stays the same length.
Myosin filament structure
Globular head which attaches to binding site on actin filament. Refers to as actin myosin binding site
What is tropomyosin
A protein that blocks the actin myosin site at rest
What is the sources of atp
Phosphocreatine
Anaerobic
Aerobic
Role of atp in muscle contraction
Hydrolyse during the power stroke
Another molecule of atp is hydrolysed to break the cross bridge
Muscle contraction stops when ca+ ions leave sarcoplasm
How lactic acid effects muscles
Lowers ph level
Muscles fibres denature
Can’t grasp onto muscle as much as
