October 25, 2023 Flashcards
which MU has more Mitchondria type 1 fibres (Type I) or type 2 fibres (Type IIA + Type IIX)
type 1
which MU activates first type 1 fibres (Type I) or type 2 fibres (Type IIA + Type IIX)
type 1 because they are small and have many excitatory inputs
Type 2 are harder to activate becuase they don’t have as many excitatory input and takes more effort
Fatigue resistance is associated with more mitochondria and better blood flow. true or false
true
Do type 2 fibres (Type IIA + Type IIX) have high or low glycolytic enzyme, glycogen and PCr
High
these products are all used in anaerobic metabolism which type 2 fibres are associated with
Do type 1 MU have high or low intramuscular triglycerides (IMTG)
high
what is histochemistry staining
Histochemistry staining, is a technique used to visualize and differentiate various components within biological tissues. It involves the application of specific stains, dyes, or chemical reagents to highlight and colorize different cellular structures, molecules, or substances, making them visible under a microscope.
Dark fibres have a lot of mitochondria and vice versa
what is dystrophin
Dystrophin is a protein (located in sarcolemma) that plays a critical role in muscle function, particularly in skeletal and cardiac muscles.
It is encoded by the DMD (Duchenne muscular dystrophy)
is mean arterial blood pressure higher or lower in subjects with a high percentage of type 1 fibers. and why
BP is lower in type I because the pressure can be distributed more evenly since there are more capillaries than in type II
more capillaries –> more space –> less pressure
How to Sample Muscle to Determine Fibre Type
- Use a needle biopsy
- Developed by J. Bergstrom in 1962
- Mainly using the vastus lateralis of the thigh muscle
Immunohistochemistry:
using antibodies to analyze different types of myosin
(different antibodies react differently to different types of myosin)
how is Insulin resistance related to the capillary density of skeletal muscle
those with fewer capillaries (high percentage of type II fibres) experience greater insulin resistance. Also, Glut4 is higher in Type I fibres
how is Obesity: especially abdominal obesity, related to a high percentage of type II fibres
Type II fibres are lower in mitochondria and mitochondria are what break down fat
If you don’t have many mitochondria, like in type II, lipid oxidation is not promoted and you will store the fat
In a person with a high percent of type II fibres, any force generated (or load lifted) can be done with a greater velocity. explain why
Type II fibres have a faster isoform of myosin → greater unloaded or loaded shortening velocity
More power is possible, since power = force X velocity (P = F x V = F x d/t = work/time)
These characteristics are evident in sprinters and jumpers, however, these athletes also show the greatest fatigability and have a greater risk associated with disease
what is the formula for power
power = force X velocity
(P = F x V = F x d/t = work/time)
Endurance Training Adaptations lead to increased….
increased mitochondria, and more capillaries
Increased in capillary to fibre ratio
Angiogenesis: synthesis and generation of new
capillaries
Increased lipid use
Increased blood flow capacity
Endurance Training Adaptations lead to decreased….
*Decreased glycogen use and lactate production
because we are using less glycogen, we are going to produce less lactate since glycolytic pathway produces lactate
*Decreased diffusion distance = better (oxygen is going only where it needs to go)
what is Angiogenesis
synthesis and generation of new capillaries
what is Mitochondrial biogenesis:
synthesis of new mitochondria
what are some Resistance Training Adaptations
Muscle enlarges by hypertrophy, not hyperplasia (not making more, just increased the size of fibres)
Enlargement is due to increase in actin and myosin gene expression
While strength can increase, it is possible for endurance to decrease
Higher diffusion distance
Effect of Concurrent Strength and Endurance Training
When you do both kinds of training, research indicates that you can increase VO2 max like with endurance training alone, but strength gains do not match resistance training alone
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Muscle hypertrophy results from:
An increase in protein synthesis, initiated by the mechanical effects of contraction on a signaling pathway in each muscle cell
An increase in muscle cell nuclei, donated from small, neighboring satellite cells, which fuse to the muscle cell in response to contractions
explain the steps involved in Muscle hypertrophy
Intense muscle contractions lead to IGF-1 synthesis and secretion
Insulin-like growth factor goes into the extracellular fluid and attaches to a receptor on the same cell that made it (autocrine)
Activates a signalling pathway involving kinases (Akt)
Akt phosphorylates and activated mTOR
mTOR activates protein synthesis in muscle (actin, myosin, etc.); makes more mRNA and all of the things required to synthesize new proteins/transcription
As a result, you get hypertrophy
