Muscles Flashcards
What is the structure of Skeletal muscle?
Skeletal muscle is voluntary. It is striated, and multinucleated.
What is the structure of Cardiac muscle?
Cardiac muscle is involuntary. It is striated, and has a single nucleus.
What is the structure of Smooth muscle?
Smooth muscle is involuntary. It is non-striated and has a single nucleus.
What is the muscle cell called? What is it made up of?
One Muscle fibre is one muscle cell. It is made up on many myofibrils.
Where are the Epimysium, Perimysium, and Endomysium?
1) Epimysium is around the muscle belly. 2) Perimysium is around one Fasicle (many muscle cells 3) Endomysium around one Muscle cell.
How are myofibrils arranged?
Myofibrils are made up of many sarcomeres, which are the main units of muscle contraction.
What are Isometric, Concentric and Eccentric muscle contraction?
I - No change in muscle length. C - Muscle shortens. E - muscle lengthens.
What three muscle fibre types are there?
Type I - Slow Oxidative. Type IIa - Fast Oxidative Glycolytic. Type IIb - Fast Glycolytic.
What are Slow Oxidative Muscle fibres? What are they used for?
Fatigue resistant, smaller diameter. Low myosin ATPase activity, but high oxidative capacity. Used for postural stability.
What are Fast Oxidative Glycolytic (IIa) Muscle fibres? What are they used for?
High myosin ATPase activity. Both high oxidative and high glycollytic capacity.
What are Fast Oxidative (IIb) Muscle fibres? What are they used for?
Fatigue easily, larger diameter. High myosin ATPase activity, high glycolytic capacity. Used in power e.g. jumping.
Where might muscle fibre types differ in muscle?
In different muscles, within muscles themselves, between different species.
Give an example of muscles that may have high slow and fast muscle fibres.
1) Fast fibres e.g. flying, running etc.
2) Slow fibres e.g. standing.
Which muscle type would contain more mitochondria? How can this be stained?
Slow muscle. You can stain for Succinate Dehydrogenase (stored in mitochondria)
Where within a muscle would you expect there to be more slow muscle fibres?
Deep (closer to the bone) postural muscle would most likely have more slow fibres than more superficial muscles.
Give 4 circumstances in which muscle adapts.
Growth, Nutrition, Excercise, Ageing.
How does muscle adapt in growth?
Hypertrophy of muscle fibres, but there is NO change in number of fibres. Possible change in arcitecture (pennate vs. parallel)
Which muscle fibres hypertrophy most in strength training?
In specific ‘strength’ training, Fast fibres hypertrophy twice as fast as slow fibres.
When a muscle changes in length (excercise), what happens to the number of sarcomeres?
Chronic stretch = New sarcomeres
Shortened position = Decreased number.
When a muscle changes in length (exercise) where are sarcomeres added? What type of sarcomeres are they?
Fibres are added at the myotendinous junction. Regardless of parent type, they are ALWAYS slow sarcomeres.
Why is it important to consider type of training, as well as amount?
It is difficult to train for increased anaerobic capacity, as increased use makes more ‘slow’ fibres, and causes hypertrophy.
What is the best way to increase Fast twitch muscle fibres?
Resistance training e.g. strength training.
What happens in detraining? What happens to the fibre types?
Happens 2x as quickly as training. Fibre types return to Type II. Anti-gravity muscles are most at risk.
What are satellite cells?
Stem cell like cells in muscle, between BM and CM. Important in hypertrophy and muscle memory.
