Download Muscle Metabolism - Liberty Union High School District

Muscle Metabolism
• Aerobic respiration: produces large
amounts of ATP but requires O2 to
function, waste products: water, CO2
• Anaerobic fermentation: produces
small amounts of ATP in absence of
O2 waste product: lactic acid (major
factor in fatigue)
Muscle Metabolism
• There are three phases to
muscle metabolism
• Each is designed to give muscle
tissue energy during strenuous
activities
Muscle Metabolism
1.
•
Immediate energy: during intense
exercise oxygen is quickly depleted in
muscle(6sec) so ATP is made by grabbing
Pi from donor molecules and adding it to
ADP to make ATP
Donor molecule: Creatine kinase grabs a
Pi from creatine phosphate (CP) and adds
to ADP to make ATP, nearly all ATP during
short burst are produced this way
(phosphagen system)
Muscle Metabolism
2. Short term energy: once the
phosphagen system is depleted the
body goes into anaerobic
respiration. It can generate energy
for 40 sec in intense activity
3. Long term energy: after 40 sec the
body cardiovascular system
catches up and is able to deliver
the needed oxygen to the muscles
for aerobic respiration
Fatigue
• Fatigue: the gradual weakness and
loss of contractility
• ATP production decreases as
glucose is used up
• Low levels of ATP slows Na/K pumps
• Lactic acid inhibits ATP production
• K+ in the ECF makes cell less
excitable
• ACh becomes depleted
Oxygen Debt
• Oxygen Debt: occurs after exercise. Due
to the following
• Oxygen reserves: oxygen is dissolved in
tissues in the body that are depleted first
and need to be replaced
• Phosphagen system: ATP must be made,
then broken to give Pi back to creatine
• Oxidizing lactic acid: most of lactic acid
will be converted into glucose in the
presence of oxygen
• Metabolic rate: if body temp is high the
metabolic rate is high and requires oxygen
to break down molecules
Muscle Fibers
• Slow oxidative (SO): Red fibers with
lots of mitochondria and blood
capillaries better for aerobic activity
• Fast glycolytic (FG): White fibers
with large storage of phosphagen
and lactic systems better for quick
responses but not endurance