October 25, 2023

Question 1

which MU has more Mitchondria type 1 fibres (Type I) or type 2 fibres (Type IIA + Type IIX)

Answer 1

type 1

Question 2

which MU activates first type 1 fibres (Type I) or type 2 fibres (Type IIA + Type IIX)

Answer 2

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

Question 3

Fatigue resistance is associated with more mitochondria and better blood flow. true or false

Answer 3

true

Question 4

Do type 2 fibres (Type IIA + Type IIX) have high or low glycolytic enzyme, glycogen and PCr

Answer 4

High

these products are all used in anaerobic metabolism which type 2 fibres are associated with

Question 5

Do type 1 MU have high or low intramuscular triglycerides (IMTG)

Answer 5

high

Question 6

what is histochemistry staining

Answer 6

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

Question 7

what is dystrophin

Answer 7

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)

Question 8

is mean arterial blood pressure higher or lower in subjects with a high percentage of type 1 fibers. and why

Answer 8

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

Question 9

How to Sample Muscle to Determine Fibre Type

Answer 9

• Use a needle biopsy
• Developed by J. Bergstrom in 1962
• Mainly using the vastus lateralis of the thigh muscle

Question 10

Immunohistochemistry:

Answer 10

using antibodies to analyze different types of myosin
(different antibodies react differently to different types of myosin)

Question 11

how is Insulin resistance related to the capillary density of skeletal muscle

Answer 11

those with fewer capillaries (high percentage of type II fibres) experience greater insulin resistance. Also, Glut4 is higher in Type I fibres

Question 12

how is Obesity: especially abdominal obesity, related to a high percentage of type II fibres

Answer 12

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

Question 13

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

Answer 13

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

Question 14

what is the formula for power

Answer 14

power = force X velocity

(P = F x V = F x d/t = work/time)

Question 15

Endurance Training Adaptations lead to increased….

Answer 15

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

Question 16

Endurance Training Adaptations lead to decreased….

Answer 16

*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)

Question 17

what is Angiogenesis

Answer 17

synthesis and generation of new capillaries

Question 18

what is Mitochondrial biogenesis:

Answer 18

synthesis of new mitochondria

Question 19

what are some Resistance Training Adaptations

Answer 19

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

Question 20

Effect of Concurrent Strength and Endurance Training

Answer 20

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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Question 21

Muscle hypertrophy results from:

Answer 21

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

Question 22

explain the steps involved in Muscle hypertrophy

Answer 22

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