Glycolytic Energy System (System 2)

Question 1

How does Blood Glucose Homeostasis work?

Answer 1

Pancreas uses endocrine glands to sense blood glucose level.

If high: Pancreas releases Insulin to allow Glucose to be absorbed by the Liver from the blood.

If low: Pancreas releases Glucagon to break down Glycogen stored within the Liver to be released back into the blood.

Question 2

What happens to Glucose in response to exercise?

Answer 2

Carbohydrate Oxidation by the working muscle is increased.
Blood glucose is preserved at the expense of Glycogen reservoirs.
Glucose get trapped within muscle and can only be untrapped by Liver.
As muscle is using Glucose, Liver is replenishing (takes 0-2 hours)

Question 3

True or False: Athletes store more glycogen in muscles than regular people.

Answer 3

True

Question 4

During exercise, what is evident of Glucose and what is this dependent upon?

Answer 4

Turnover of ATP in skeletal muscle increases greatly and muscle glucose uptake increases substantially.
This is dependent upon intensity & duration.

Question 5

True or False: The shorter a workout is, the more Glucose that is used.

Answer 5

False

Question 6

Does Insulin bring in Glucose? If not, what does and how?

Answer 6

Insulin doesn’t bring glucose within a cell.

Instead, insulin brings up Glucose Transporters within the cell to allow Glucose in.

Question 7

At rest, what is the job of Insulin?

Answer 7

Control/Regulate Glucose uptake

Question 8

How and what does Insulin signal to accumulate Glycogen?

Answer 8

Insulin increases to increase Glucose uptake and Glycogen storage.
It does this by binding to its receptor which mediates its signal to target proteins.
This leads to transduction of glucose transporters in Liver (GLUT-1) & Muscle (GLUT-4).

In a nutshell: Insulin Signaling —-> Glucose Transporter or Glycogen Synthase Activity —-> Glycogen Accumulation

Question 9

Describe exercise-related Glucose transport.

Answer 9

Muscle contraction & ATP breakdown
Mitochondrial respiration & formation of ROS
Which stimulates AMPK & PI3-k cascade.
GLUT-4 is translocated to the sarcolemma & T-tubles
Hexokinase phosphorylates gluecose irreversibly, which traps glucose in cell.

Question 10

What does Insulin signaling signal?

Answer 10

Increases Glucose & Glycogen storage

Question 11

How does Insulin lead to Autophosphorylation?

Answer 11

Insulin binds to its receptor, which mediates its signal to target proteins, leading to translocation of glucose transporters.

Question 12

What are the names of the Glucose transporters in the Liver and Muscle?

Answer 12

Liver = GLUT - 1
Muscle = GLUT - 4

Question 13

Does Insulin signal transduction control/regulate glucose uptake at rest or during exercise?

Answer 13

At rest

Question 14

Describe what two routes Insulin signaling can take.

ON TEST

Answer 14

Insulin Signaling –> Glucose Transport –>Glycogen Accumulation
OR
Insulin Signaling –> Glycogen Synthase Activity –> Glycogen Accumlation

Question 15

At rest, what is the primary job of insulin?

Answer 15

To synthesize Glycogen for Glucose Uptake

Question 16

How does muscle contraction & ATP breakdown create Insulin independent Glucose uptake?

Answer 16

Exercise stimulates mitochondrial respiration & formation of free radicals
Translocation of GLUT - 4 to Sarcolemma
Hexokinase phosphorylates Glucose irreversibly
Glucose is trapped in cell independently of insulin

Question 17

True or False: The less Glycogen used, the greater the demand for Glucose.

Answer 17

False. Glycogen and Glucose have an inverse relationship, so if there were less Glycogen used, the would be a lesser demand for Glucose.

Question 18

True or False: Glycogen synthesis is the primary disposal route for Glucose at rest.

Answer 18

True

Question 19

True or False: Glucose is irreversibly trapped when in muscle.

Answer 19

True

Question 20

What energy source & type are used in this energy system?

Where is this energy used?

Answer 20

Source = Glygolysis
Type = Anaerobi
Location = Cytosol