Muscle Flashcards
Muscle
Highly specialized tissue with ability to contract in response to stimuli
What three types of muscles do vertebrates have?
skeletal, cardiac, smooth
what is the organization of the muscle?
muscle–> muscle fiber–> myofibril
sarcomere
The basic unit of contraction. gives muscle a striated appearance.
Myosin contains what two kinds of filaments?
1.Thick filaments;
– Composed primarily of myosin;
2. Thin filaments;
– Composed of two chains of globular actin, wrapped around each other in a helix;
Titin
Structural elastic protein that align actin and myosin;an accessory protein for contraction.
What do tropomyosin and troponin do>
Associated with the actin chains of the thin filaments;
– Regulate contraction by controlling the interaction of the cross bridges with the thin filaments.
What happens during a muscle contraction?
the muscle fibbers contract, the thin and thick filament slide over each other.
what are the signals for a muscle contraction?
Motor neurons from the somatic NS generate action potentials that liberates ACh

ACh is secreted into the neuromuscular junction and binds to nicotinic receptors in the muscle cell membrane

Ca2+ is liberated from the sarcoplasmic reticulum

what does myosin ATPase catalyze?
the decomposition of ATP into ADP
In the absence of calcium what does tropomyosin do?
tropomyosin cover myosin-binding sites;
The binding of Myosin to actin create the formation of what?
crossbridge
where is calcium taken once the action potentials stop after muscle contraction?
sarcoplasmic reticulum.
What are the 3 types of muscle fibbers?
– Slow oxidative fibres; – Fast oxidative fibres; – Fast glycolitic fibres.
oxidative fibers
Contain large number of mitochondria:
– High capacity for oxidative phosphorylation:
– Surrounded by many small blood vessels;
What colour of meat is oxidative fibbers?
Red meat. i.e breast of a duck
glycolytic fibers
Few mitochondria but high concentration of glycolytic enzymes and large stores of glycogen;
– Limited use of oxygen;
– Few blood vessels
– Little myoglobin,
What are the 3 major types of muscle fibers>
- slow oxidative fibers
- fast oxidative fibers
- fast glycolytic fibers
slow oxidative fibers
Have low rates of myosin ATPase activity but have the ability to make large amounts of ATP
– Do not fatigue easily;
– Used for prolonged, regular activity;
• flight, long-distance swimming;
Fast oxidative fibers
Fast-oxidative fibres:
– Have high myosin ATPase activity and can make large amounts of ATP;
– Do not fatigue quickly and can be used for long-term activities;
– They are particularly suited for rapid actions;
fast glycolytic fibers
High myosin ATPase activity but cannot make as much ATP as oxidative fibres, because their source of ATP is glycolysis;
• Best suited for rapid, intense actions;
– Short sprint at maximum speed or a cat
pouncing on its prey;
• Fatigue more rapidly than oxidative fibres;
Aerobic exercise of low intensity but long duration, increase what?
the number of mitochondria in the slow-oxidative fibres;
High-intensity exercise of short-duration affects what?
fast-glycolytic fibres, which are used during strong contractions:
What type of muscles are striated muscles?
Skeletal muscle and cardiac muscle
