Topic 6 Skeletal Muscle Fiber types Flashcards
RE. Skeletal muscle types, not all skeletal muscle fibres are the same - differences include (3)
the speed which they generate tension
how they use different energy substrates
how they fatigue
There are 3 main types of skeletal muscle fibre
1) Slow oxidative
2) Fast Oxydative-Glycolytic (FOG)
3) Fast Glycolytic
True/False
The forcefulness of contraction (ability to generate force) depends on the length of the sarcomeres within a muscle BEFORE the contraction begins
True
Greatest ability to generate tension
Optimal overlap (resting tension) ***Mid range - greatest capacity to generate force
Decreased ability to generate tension - 1
Minimal overlap (lengthening)
Decreased ability to generate tension - 2
Excessive overlap
Types of contractions…
muscle contraction through a range against a resistance that is not changing
Isotonic
Iso=Same Tonic=Assistance
Types of contractions…
a shortening contraction
Concentric
Types of contractions…
a lengthening contraction
Eccentric
Types of contractions…
muscle contraction which the length of the muscle does not visibly change
Isometric
Iso=Same Metric=Measurement
Types of contractions… NEW
muscle contraction through a range in which equipment varies the resistance to match the length of the curve
Variable resistance
Types of contractions… NEW
muscle contraction through a range in which equipment keeps the same velocity of movement constant
Isokinetic
Iso=same Kinetic=Movement
Re. muscle tone…
a small amount of tension being generated in the muscle;
not strong enough to produce motion
Resting tone
*resistance in tissue
muscle term
a brief contraction of all the muscle fibres in a motor unity in response to a single AP in its motor neuron
Twitch contaction
*single motor unit level - usually
muscle term
a lack of tone from the nerve being damaged or cut
Flaccidity
*nerve has reconnected if you see a twitch during rehab
muscle term
increase in muscle size
Hypertrophy
*muscle growth
muscle term
decrease in muscle size
Atrophy
*decrease in muscle size
Types of muscle fatigue (5)
1) inability of a muscle to function at the required level
2) energy substrate depletion
3) metabolic by-products (eg. heat interfering with muscle performance
4) neurological fatigue (eg physiology - overworked muscles)
5) central nervous system fatigue (eg Drive/ motivation is affected depression - speaks to motivation)
Re. muscle regeneration…
They are undifferentiated muscle cells;
actively involved in muscle repair and regeneration;
capacity is limited
Satellite cells
*stem cells for muscles
Re. muscle connective tissue…
it surrounds the entire muscle
Epimysium
Re. muscle connective tissue…
it surrounds the fascicles
Perimysium
Re. muscle connective tissue…
it surrounds the muscle fibre
Endomysium
Tendons are an extension of muscle cells
eg. the epimysium, perimysium, endomysium are all interconnected;
They extend beyond the muscle fibres to connect the muscle to the periosteum (or other structures)
these connections are known as junctions
The transition from muscle tissue to tendon
musculotendendinous junction
The transition from tendon to periosteum
tendoperiosteal junction
Its known as a ‘broad, flat, tendon
Aponeurosis
A tube that surrounds a tendon to protect it
Tendon sheath
Type of muscle…
> Same actin/ myosin arrangement as skeletal muscle;
> Fibres are branched - the ends are fit tightly together with neighbouring fibres called intercalated discs;
> Anchoring junctions hold them together;
> Gap junctions allow for cells to communicate quickly
> involuntary control (electric synaps)
Cardiac muscle
Re. Autorythmicity…
What type of muscle has specialized cells that can generate their own electric signals;
They act as a pacemaker
Cardiac muscle
Type of muscle... > Found in the walls of hollow tubes; > Spindle shaped > have gap junctions > involuntary control > contractions start slowly and last longer
Smooth muscle
Smooth muscle has 2 types of tissue ?
1) single unit smooth muscle tissue
2) multi unit smooth muscle tissue
Type of smooth muscle tissue…
One AP supplies smooth muscle fibres…
> Via gap junctions, they operate as a single unit;
> walls of small arteries, hollow organs
single unit smooth muscle tissue
Type of smooth muscle tissue…
One motor neuron terminal supplies one smooth muscle muscle fibre
> Via few gap junctions;
> Walls of large arteries, airways in lungs, erector pilli, muscle of iris
multi unit smooth muscle tissue
