More on muscle :) Flashcards
there are 2 categories of individual fibre types, name them.
Fast twitch and Slow twitch
Name the fibre that is called a slow fibre.
Type I
Type I are slow-______ fibres and slow-______ fibres.
twitch, oxidative
Type I fibres have large amounts of ________.
mitochondria
Type I fibres have a high _____ concentration.
myoglobin
Name the 2 types of fast fibres.
Type IIb and Type IIa.
Type IIb are fast-_____ fibres and fast-_____ fibres.
twitch, glycolytic
Type IIb fibres are _____ in diameter.
diameter
Type IIa are called _____ fibres.
intermediate
Type IIa are _____-oxidative fibres.
fast
What is Type IIa described as?
A hybrid of type I and type IIb, eg. in between them :)
What fibre types will power athletes and sprinters have a high percentage of?
they will have a high % of fast fibres.
______ athletes and ____ runners will have a high % of slow fibres.
endurance, distance
Non-athletes have ____% slow and ____% fast fibres.
50, 50
What size are Type I fibres?
small
what colour are type I fibres?
red
myoglobin brings _____ to muscles.
oxygen
Type IIa are _____ in size and are _____ in colour.
intermediate, pink
What is the myoglobin and mitochondrial content of IIa fibres?
Medium for both :)
What colour are IIb fibres and why?
White as they have low myoglobin concentration.
Type IIb fibres have low ______ content.
mitochondrial.
The resting tension in a muscle is called muscle ______.
tone
Name a sensory unit associated with a tendon that is responsible for preventing damage to the associated muscle.
Golgi tendon organ
Muscle tone is controlled by the sensory ______ ______, which measures muscle stretch.
muscle spindle
Why is muscle tone important?
it is important for generating reflexes,
maintaining posture and balance,
and controlling proper function of other organ systems.
Name the 2 muscle contraction types.
Isotonic contraction and Isometric contraction
What does isotonic contraction do?
It changes skeletal muscle length
What does isotonic contraction result in?
Motion
What happens if muscle tension is greater than the load?
The muscle shortens (concentric contraction)
What happens if muscle tension is less than load?
the muscle lengthens (eccentric contraction)
_____ contraction is when the muscle shortens to 70% of its original length.
Concentric
_____ contraction is when the muscle lengthens/elongates to 140% of its original length.
eccentric
Raising a weight during a bicep curl is an example of____ contraction.
concentric
Lowering a weight during a bicep curl is an example of ______ contraction.
eccentric
What is isometric contraction?
The skeletal muscle develops tension but is prevented from changing length.
What happens to the length of the muscle during isometric contraction?
It stays the same.
_____ and _____ of contraction are inversely related.
load, speed.
The heavier the load (resistance) on a muscle the ______ it takes for shortening to begin.
longer
If there is a heavier the load, the less the muscle will ____.
shorten
What is a muscle twitch?
A contraction as the result of a single stimulus.
Name the 3 periods of muscle contraction/relaxation.
Latent period
contraction period
relaxation period
How long does the latent period last for?
2/3 m/secs
During contraction, what is developed?
Tension
The ___ period lasts 15 m/s.
contraction
how long does the relaxation period last?
25 m/s
Why is there always a latent period?
As the muscle has to overcome lots of resistance.
In the muscle twitch diagram right between contraction and relaxation is the highest point on the graph, what is this known as?
Peak Tension
The _____ shows differences in tension over time for a twitch in different ____ muscles.
myogram, skeletal
The best length-tension relationship is referred to as the muscle’s what?
Optimum Resting Length
If the sarcomere is too small in length, what will happen?
There will be no room for sliding filament to have any effect so no tension will be produced.
If the sarcomere is too long what will happen?
There will be no interaction between filaments and no tension will be produced.
the _____ _______ length is 75%-130% of the optimal length.
normal sarcomere
1.2 micrometres- 3.6 micrometres is known as a sarcomere’s ______ _______.
operating range.
Name the 3 areas affecting force regulation in muscles.
- The type and number of motor units recruited
- Initial muscle length
- Frequency of stimulation
If there are more motor units there will be a _____ ______.
greater force
If there are ______ motor units there will be a greater force.
fast
What (in terms of initial muscle length) produces the greatest amount of tension?
Optimum Overlap
The nature of the _____ _____ neural ______ affects force regulation.
motor unit, stimulation
The ____ of stimulation affects force regulation.
frequency
Name the 3 types of muscle frequencies that you can get.
Simple twitches, summation then tetanus.
As we increase the frequency then the muscle won’t have as much time to ______.
recover
If the stimulus is not that frequent, ____ _____ will occur.
simple twitches
When the stimulus becomes slightly more frequent this will cause _______ and an increase in _____.
summation, force
A very frequent stimulus results in high force, this is known as ______. But the muscles will get tired and then force will drop to nothing if overworked :)
tetanus
Name the 2 receptors in muscle.
Muscle spindle and Golgi Tendon Organ
What do muscle spindles detect?
(Dynamic and static) changes in muscle length
___ reflexes are involved with muscle spindles.
stretch
Stretch on muscle causes _____ ______.
reflex contraction
What does the Golgi tendon organ monitor?
They monitor tension developed in muscle.
If the Golgi tendon organ detects a change what happens?
The loop system kicks in.
What does the Golgi tendon organ prevent?
It prevents damage during excessive force generation
Golgi tendon organ- stimulation results in reflex ________ of muscle.
relaxation
We “spot” people at the gym due to this reflex _____ of muscle if a change in tension is detected.
relaxation
What is muscle fatigue?
When a muscle can no longer perform at the required level of activity.
When a muscle fatigues what is there a depletion in?
There’s a depletion of metabolic reserves.
During muscle fatigue there is a decline in ____ within the muscle fibre due to ______ _____ build up.
pH, lactic acid
Why do you get a sense of weariness when your muscles fatigue?
Due to low blood pH
____ ______ can lead to damage to the sarcolemma or sarcoplasmic reticulum.
Muscle Fatigue
A pathological condition can be premature muscle fatigue, what can this cause?
heart problems and blood loss etc.
What is muscle atrophy?
The reduction in muscle fibre size, tone and power.
What causes muscle atrophy?
Lack of activity (or loss of neural innervation)
Sedentary lifestyle, bed rest and spinal cord injury can result in what?
Muscle Atrophy
What is muscle hypertrophy?
Muscle fibre increases in diameter (aka. gains) ;)
What causes muscle hypertrophy?
repeated, exhaustive stimulation- due to training
In hypertrophy what remains the same?
The number of muscle fibres remain the same, just the size increases
What would cause an increase in mitochondria, glycolytic enzymes and larger glycogen reserves?
Muscle hypertrophy
The process of contraction involves firstly the ___ ______ of ________.
neural stimulation, sarcolemma
What does neural stimulation of sarcolemma then cause?
It causes excitation-contraction coupling
The interaction between thick and thin filaments is known as _____ ______ _________.
muscle fibre contraction
What does contraction of muscle produce?
Tension/Force production
