1. Muscle Metabolism

2. Muscle metabolism ATP is energy source for contraction
HOWEVER, muscle fibers only have enough ATP to contract for a short time
ATP must then be regenerated from ADP and P by the muscle cell:
creatine phosphate is the molecule that makes this possible
Creatine phosphate has high energy phosphate bonds

3. Muscle metabolism
When ATP supply is sufficient enzyme creatine phosphokinase
(in the mitochondria) catalyzes the synthesis of creatine phosphate.
Creatine phosphate stores energy in high energy phosphate bonds
Creatine phosphate is 4-6 X more abundant in muscle cells than ATP
BUT it Cant be used directly as an energy source
So as energy from ATP is released and ADP is produced, creatine phosphate transfers energy to ADP to become ATP
Active muscles uses creatine phosphate quickly so cell respiration is required to generate more ATP

4. Creatine Supplements
Creatine Supplements

5. O2 and Cellular Respiration
Aerobic respiration is a more complete
breakdown of glucose
When O2 is present; mitochondria
produce 36 ATP per 1 glucose
(oxidative phosphorylation)
Oxygen is delivered to the muscle by
Red blood cells by 2 pigments:
1. Hemoglobin is pigment that carries O2
2. Myoglobin another pigment- is a
molecule with high affinity to oxygen and
is produced in the muscle cells

6. Oxygen Debt Strenuous use, Need anaerobic respiration
glycolysis :2 ATP formed per glucose and synthesis of lactic acid
Consequence of anaerobic metabolism?
FATIGUE
Figure 12.11

7. Liver and Lactate

8. Liver and Lactate

9. Types of physical training
High intensity, short burst exercise:
Depend on more glycolysis
Synthesize more glycolysis enzymes
Aerobic Exercise
form more capillaries and mitochondria

10. Muscle fatigue Muscle fatigue: muscle loses ability to contract
due to prolonged use
Caused by:
Decreased ATP
Electrolyte imbalance
Causes:
- rapid build-up of lactic acid
- decrease in oxygen supply
- decrease in energy supply (glucose, glycogen, fatty-acids)
Decreased neurotransmitter at the synapse
- psychological causes

11. Cramp When muscle is fatigued Sustained involuntary contractions
Changes in extracellular fluid surrounding muscle fibers trigger uncontrolled stimulation of muscle
Due to Low sodium, potassium, magnesium
Nocturnal cramps due to dehydration

12. Heat production 40% of energy in glucose released as ATP
Rest released as heat
Blood transports heat to maintain homeostasis

13. Maxine