L19 (integration)

Question 1

what happens during excersize

Answer 1

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.

Question 2

what are the different types of muscle fibers

Answer 2

type 1 (slow twitch)

type 2 (a and x) fast twitch

Question 3

what is the difference between type 2 a and x fibers

Answer 3

type 2 a fibers which are intermediate fibres

type 2 x fibres which are the really fast explosive fibres.

Question 4

what is a muscle biopsy

Answer 4

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.

Question 5

what does the composition of your muscle fibers come down to

Answer 5

gene pool and what your parents got you to do when you were younger

Question 6

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

Answer 6

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

Question 7

what is magnetic resonance spectroscopy

Answer 7

an MRI

Question 8

how do you use MRI to see muscle fiber types

Answer 8

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.

Question 9

what is the role of carnosine

Answer 9

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

Question 10

what produces carnosine

Answer 10

beta alanine

Therefore beta alanine is a supplement that athletes will take to increase there buffering capacity which is an advantage for some sports

Question 11

describe the characteristics of type 1 fibers

Answer 11

High aerobic endurance

can maintain exercise for prolonged periods
require oxygen for ATP production

Efficiently produce ATP from fat and carbohydrate

Question 12

describe the characteristics of type 2x fibers

Answer 12

type 2 fibers have poor aerobic endurance, fatigues quickly

Type 2x (fast)

• Seldom used for everyday activities
• Short, explosive sprints (100m run)

Question 13

describe the characteristics of type 2a fibers

Answer 13

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)

Question 14

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

Answer 14

A

Question 15

what is Phosphocreatine (PCr) role in ATP recycling

Answer 15

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

Question 16

how long do you have until your PCr stores in the muscle run out during excersize

Answer 16

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

Question 17

what kind of process is Phosphocreatine (PCr) role in ATP recycling

Answer 17

This is an anaerobic process

Question 18

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

Answer 18

fast ATP generation = glycolysis pathway

show ATP generation = cystic acid pathway (TCA)

Question 19

describe the glycolytic pathway

Answer 19

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

Question 20

is the glycolytic pathway anaerobic or aerobic

Answer 20

• This pathway is anaerobic

Question 21

where does the glycolytic pathway take place

Answer 21

• it happens in the Cytosol

Question 22

how much ATP does the glycolytic pathway make

Answer 22

• ATP yield: 2 ATP per glucose (use 2, generate 4)

Question 23

how long does the glycolytic pathway take to produce energy

Answer 23

• Duration: 15 s to 2 min

Question 24

describe the oxidative phosphorylation pathway (slow ATP generation)

with pyruvate

Answer 24

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

Question 25

describe the oxidative phosphorylation pathway (slow ATP generation) makes energy with FFA

Answer 25

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

Question 26

what is the most efficient way of producing energy

Answer 26

from fats

Question 27

how much ATP can you make from a single trigliseride

Answer 27

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

Question 28

when/how is protein used as a fuel source

Answer 28

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

Question 29

how is protein used to produce energy

Answer 29

it can be converted to glucose via gluconeogenesis but this is not a very efficient process

Question 30

what % of fuel source does protein provide

Answer 30

2-5%

Question 31

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

Answer 31

C

Question 32

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

Answer 32

C

Question 33

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

Answer 33

B

Question 34

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

Answer 34

B

marathon runner would be A) type 1

400m runner would be type 2a?