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Flashcards in Lecture 4 Deck (15)

What are some signals in contracting muscles?

Glycogen, lactate, H+, ROS
Tension, length


How do intracellular signals affect muscles?

Signals can affect muscles in various ways; this can be at the transcription, translation, and post-translation level.


How does exercise intensity affect CAMK2 levels?

Exercise increases Ca2+ -calmodulin-dependent protein kinase in skeletal muscle. More at high intensity exercise and less at lower intensity exercise.


Where does AMPK come from?

AMP-activated protein kinase is fromed as a result of ATP breakdown.


What are the stimulatory effects of AMPK?

Heart takes in more glucose and increases FA oxidation and glycolysis.

Brain creates behaviour response to take in more food.

Skeletal muscle increase FA oxidation, glucose uptake, expression of GLUT4 and increases number of mitochondria.


What are the inhibitory effects of AMPK?

Anabolic pathways are turned off including insulin secretion, FA synthesis and gluconeogenesis.


When is AMPK found in muscles?

During high intensity exercise more AMPK is found in muscles.


What happens to ATP levels in the body at high intensity?

ATP is relatively constant at all intensities indicating the body is good at maintaining ATP levels.


How does AMPK increases GLUT4 production?

AMPK is an important signal in the adaptive response. It increases GLUT4 levels. It also increases calcium levels which stimulates CaMK2.
Stimulation of AMPK and CaMK2 causes these enzymes to phosphorylate a suppressor. Doing this results in more GLUT4 production.


What is GLUT4?

GLUT4 is the main glucose transporter that responds to insulin it facilitates glucose transport into the muscle which allows restoration of glycogen more rapidly.


How do ROS increase the adaptive response to exercise?

ROS at lower concentrations act as signalling molecules. They increase kinase activity and decrease phosphatase activity. Phosphorylation of transcription factors is increased.
Phosphorylation of transcription factors results in more transcription.


Why is it a bad idea for athletes to take too much antioxidants?

antioxidants would act to blunt the adaptive response to exercise.


Why is it a good idea to increase IgF-1 levels?

IgF-1 creates a pathway that leads to more hypertrophy and inhibits atrophy. This pathway is inhibited by glucocorticoids.


What happens to protein synthesis during exercise and after exercise?

During recovery protein synthesis is increased but while exercising it is decreased.


How does AMPK affect the mTOR pathway?

AMPK can blunt some of the effects of mTOR.