What are muscles and why do they contract?
They are a band or bundle of fibrous tissue in a human or animal body that has the ability to contract, producing movement in or maintaining the position of parts of the body
They contract becuase they've been sent electrical impulses from the brain.
What is the difference between concentric and eccentric contractions?
A concentric contraction causes muscles to shorten, thereby generating force.
Eccentric contractionscause muscles to elongate in response to a greater opposing force.
What is the difference between Isotonic and Isometric contractions?
Isometric contractions are when the muscle is contracting without changing shape e.g. carrying a heavy box in front of you, there is nomovement, but the muscles are contracting.
Isotonic Contractions are when the muscle changes shape e.g. shortening (concentric contractions) or lengthening (eccentric contractions)
What are the three types of muscle tissue?
- Smooth - visceral organs
- Cardiac - heart
- Skeletal - attach to skeletons - we choose to move them
What is meant by muscle
- Speed of contraction
It's ability to force it can use against a restisance e.g. lifting a barbell
- Speed of contraction
How fast they get into postion e.g. concentric, eccentric or isometric
How long they can perform a task for
How poised and ready for action they are, best views in a relaxed or under slight tension.
What is meant by
- Stabilizer / fixator
- This is the main muscle we are working on
- The muscle opposite that will be extending whilst our agonist is contracting.
- Pulls against the agonist to stabilise it
- Stabilizer / fixator
- Also works to stablise the muscle, by using the bone to which it is anchored.
How does exercise impact on muscles?
Increase in muscle mass
Inscrease in muscle strength
There are 5 principle muscle characteristics, that enable it to function what are they? How do they impact?
Excitability - how it responds to a stimulus
Contractility - The ability of the muscle to shorten
Conductivity - How well a muscle cell can conduct an electrical impulse to instruct the entire muscle
Elasticity - How quickly they can go back to their original shape
Extendibility - How far they can stretch
What do we know about cardiac muscle? (Five things are listed)
- Striated (like skeletal muscle), looks like it's fused together, like chromosomes strands
- Has been known to beat unconnected to the CNS suggesting its stimulus comes from within
- Beats on average 72 times a minute
- It forms the walls and partitions of the heart
- It will die very quickly without a constant supply of blood ...hence heart attacks from insufficient blood supply
What do you know about smooth muscle? (I've listed 7 items)
- Also known as visceral muscle
- Tapered in shape
- No striations
- More elastic than the othet two
- Temperature sensitive
- Can stay in contraction for longer than the other two
- Contract slowly
Some facts about Skeletal muscles
- Under conscious control
- Made up of
- Fast twitch muscle - explosive, responds quickly
- Slow twitch muscle - slower to respond, will keep going
- Some operate between the two of them
- Fast Fibres contract more quickly and develope more tension
- Slow fibres are slower but have more endurance.
- Heredity - depends on where you come from, training in adulthoood has little effect, training in childhood may do.
- Its striated - has fibres that run across each other to forms stripes.
- Myofibrils are the smallest structure of the mucle, up to 1000 of them, they are full of filaments of protein and are the contractile filaments.
What are some characateristics of slow twitch muscle?
- Good for endurance
- Red in colour due to their myglobin content -myoglobin is an oxugen binding protein
- Narrow in diameter
- Surrounded by capillaries
- Prefer aerobic matabalism as they use oxygen to fuel the muscle cells
- Resistant to fatigue hense there being a lot of them in the postural muscles.
What are some of the characateristics in fast twich fibres?
- Well firstly there are two types
- Oxiadative (type 11a fibres)
- Glycolic (type IIb fibres) These are a lot bigger in size, they're pale pink or white due to their less generous supply of capillaries, they also havea lower myglobin content.
- In general they prefer anerobic conditions, they don't really rely on oxygen for their energy.
- Type iia mostly aerobic... which makes no fuckiing sense after you just said they dont use it!
- iib are mostly anerobic and have fuck all arobic capability