L19 (integration) Flashcards
what happens during excersize
Muscles are contracting, the respiratory rate increases, and the heart rate increases, all to allow energy to be made to allow the skeletal muscles to move faster.
what are the different types of muscle fibers
type 1 (slow twitch)
type 2 (a and x) fast twitch
what is the difference between type 2 a and x fibers
type 2 a fibers which are intermediate fibres
type 2 x fibres which are the really fast explosive fibres.
what is a muscle biopsy
A muscle biopsy is where a doctor will make an incision in the skin and use a rather large needle to extract quite a few fibres from the muscle. Use a few laboratory techniques to stain and identify the muscle fibre types to get the composition of the muscle.
what does the composition of your muscle fibers come down to
gene pool and what your parents got you to do when you were younger
type 2 x is able to shift to type 2 a
but a type 1 could not shift to a type 2
is this the case when you were younger
younger individuals there is a given proportion of hybrid fibres that share some of the characteristics of either one of these fibres, and those hybrid fibres can specialize and become either type 1 or type 2 depending on what you do at a very young age
therefore the amount of sport/type of sport you did at a young age determines a % of the fiber type you have
what is magnetic resonance spectroscopy
an MRI
how do you use MRI to see muscle fiber types
measuring a particular metabolite in skeletal muscle called carnosine.
This is 2 times higher in your muscle fast twitch fibres than your slow twitch fibres. Carnosine is very stable in muscles in response to training, and is not very responsive to diet changes.
However, one supplement that does affect is beta alanine.
what is the role of carnosine
What carisine does is it buffers the H+ ions that are produced in the mussel. There are more H+ ions produced in type 2 fibers than type 1 fibers therefore they need more carnisin
what produces carnosine
beta alanine
Therefore beta alanine is a supplement that athletes will take to increase there buffering capacity which is an advantage for some sports
describe the characteristics of type 1 fibers
High aerobic endurance
can maintain exercise for prolonged periods
require oxygen for ATP production
Efficiently produce ATP from fat and carbohydrate
describe the characteristics of type 2x fibers
type 2 fibers have poor aerobic endurance, fatigues quickly
Type 2x (fast)
- Seldom used for everyday activities
- Short, explosive sprints (100m run)
describe the characteristics of type 2a fibers
type 2 fibers have poor aerobic endurance, fatigues quickly
Type IIa (intermediate)
- More force, faster fatigue than type I
- Short, high-intensity endurance events (1500m run)
As exercise intensity increases, the recruitment order of muscle fibres is:
A) Type I, Type IIa, Type IIx
B) Type IIx, Type I, Type IIa
C) Type IIa, Type IIx, Type I
D) Only Type I motor units are recruited during exercise
A
what is Phosphocreatine (PCr) role in ATP recycling
PCr + creatine kinase = Cr + Pi + energy
PCr energy cannot be used for cellular work, however PCr energy can be used to re-assemble ATP
therefore it replenishes ATP stores during rest
yields 1ATP for 1PCr therefore it is inefficient
how long do you have until your PCr stores in the muscle run out during excersize
Recycles ATP during exercise until used up (~3-15 s maximal exercise)
Therefore some athletes take powder to try and increase their stores so that they can use this pathay for longer
what kind of process is Phosphocreatine (PCr) role in ATP recycling
This is an anaerobic process
the PCr system, is going to run out pretty fast, in fact 3-15 seconds of maximal exercise. We need another pathway to make energy
what is/are these
fast ATP generation = glycolysis pathway
show ATP generation = cystic acid pathway (TCA)
describe the glycolytic pathway
converts Glucose, a 6C compound to pyruvate, a 3C compound and in the process energy is released in the form of ATP
gets glucose from muscle glycogen stores
is the glycolytic pathway anaerobic or aerobic
• This pathway is anaerobic
where does the glycolytic pathway take place
• it happens in the Cytosol
how much ATP does the glycolytic pathway make
• ATP yield: 2 ATP per glucose (use 2, generate 4)
how long does the glycolytic pathway take to produce energy
• Duration: 15 s to 2 min
describe the oxidative phosphorylation pathway (slow ATP generation)
with pyruvate
this is the citric acid cycle (TCA)
it converts pyruvate from the glycolytic pathway into acetyl CoA
it has a much greater yield of ATP (32-34) but oxygen is needed
describe the oxidative phosphorylation pathway (slow ATP generation) makes energy with FFA
triglyceride (fats) go into the beta-oxidation pathway and then into the TCA cycle when they break down from triglyceride into 3 FFA and a glyceride
Through both the beta oxidation pathway and the TCA cycle you generate…..
- 3FFA makes 441 ATP
- Glycerol makes 19ATP
Therefore from 1 triglyceride you can generate 460 ATP
Therefore fats are the most efficient form of energy
what is the most efficient way of producing energy
from fats
how much ATP can you make from a single trigliseride
Through both the beta oxidation pathway and the TCA cycle you generate…..
- 3FFA makes 441 ATP
- Glycerol makes 19ATP
Therefore from 1 triglyceride you can generate 460 ATP
when/how is protein used as a fuel source
Keto diets and starvation
Can be used as a fuel source but is really used as a substrate as it can be converted to glucose via gluconeogenesis
This happens when someone goes into a starvation diet
This is not a very efficient way of producing energy
make up 2-5% of our fuel source
how is protein used to produce energy
it can be converted to glucose via gluconeogenesis but this is not a very efficient process
what % of fuel source does protein provide
2-5%
Which muscle fibre type are termed fatigue resistant?
A) Fast twitch (Type IIx)
B) Intermediate twitch (Type IIa)
C) Slow twitch (Type I)
D) None of the above
C
Phosphocreatine (PCr):
A) is a substitute for troponin in smooth muscle
B) destroys excess acetylcholine (ACh) at the neuromuscular junction
C) stores energy from ATP in the muscle cell
D) is a neurotransmitter found in smooth muscle
C
A muscle fibre gains 60 ATP’s from metabolism. How many glucose molecules were consumed to yield this much energy if the muscle fibre is operating anaerobically?
A) 120
B) 30
C) 38
D) 2
B
Weightlifters training anaerobically (for strength rather than endurance) emphasize which muscle type?
A) Slow twitch (Type I)
B) Fast twitch (Type Iix)
C) Neither
D) Both
B
marathon runner would be A) type 1
400m runner would be type 2a?
