Chapter 10.2 Flashcards
Why do muscle fibres rarely fatigue?
Because during active use, some are contracting and some are relaxing
What results in muscle tone?
The continuous low-level activity of muscles
What is muscle tone important for?
Maintaining posture
What would happen if there was low muscle tone in the in the body?
That would mean that all the muscles would relax and the body would collapse
What can cause muscles to become impaired?
- Sudden stress placed on muscles and tendons
- Lack of use
What is atrophy?
The reduction of size, tone, and power of muscle due to lack of use
What happens if a skeletal muscle experiences reduced stimulation?
It fibres decrease in size and become weaker
Why is physical therapy important for people with temporary injuries?
Because dead or dying muscle fibres cannot be replaced because damage is permanent.
What is hypertrophy?
An exercise induced increase in muscle mass
What cause hypertrophy?
An increase in size of muscle fibres
How does being more physically fit change the enzymes within muscle fibres?
The enzymes are more active and numerous. The mitochondria are also more abundant
Why can a runner’s muscles endure more than an untrained person’s muscles?
Because a runner’s muscles are more abundant in the mitochondria so they can go longer without having to resort to fermentation
They also receive more blood through additional blood vessels and store more glycogen
What is a muscle twitch?
A muscular contraction that lasts for a fraction of a second
What can a muscle twitch be divided into?
- Latent Period
- Contraction Period
- Relaxation Period
What is the Latent Period?
The period of time between the stimulation and initiation of contraction
What happens during the Contraction Period?
This is when the muscle shortens
What happens during the relaxation period?
This is when the muscle returns to its former length
What is summation?
A cumulative response to stimulus when the muscle doesn’t completely relax before the next stimulus
What is tetanus?
A maximal sustained contraction that results when there are multiple stimuli before the muscle contracts