Muscle

Question 1

Anaerobic glycolysis

Answer 1

• ATP production without O2
• Dependent upon lactate dehydrogenase
• Much less efficient
  – Two ATP per molecule of glucose
  – End product is still energy rich
  * Lactic acid
  – Requires oxygen to convert back to pyruvate
  ends in lactic acid and requires more oxygen to convert back to pyruvate

Question 2

Aerobic catabolism

Answer 2

• Four steps
  – Glycolysis (4-2=2)
  – Krebs cycle (2)
  – Electron transport chain (NADH2 , FADH 2 )
  – Oxidative phosphorylation (34)
• Able to process fats, carbohydrates, and
  proteins
• Net yield of 38 ATP per glucose molecule

Question 3

Muscle fatigue

Answer 3

• Fatigue- exercise induced reduction in muscle
  force generation
• Can be due to:
  – lactic acid accumulation
  – inadequate muscle glucose
  – hyperthermia
  – often due in part to cell function disruption

Question 4

Muscle Fiber Types

Answer 4

• Speed of Contraction
  
  • Differences in ATPase activity
    
    • Slow Twitch
    • Fast Twitch
• Pathways of ATP formation
  – Oxidative (red)- Type 1
  – Glycolytic (white)- Type 2

Question 5

Aerobic and anaerobic catabolism during exercise

Answer 5

• Activity level sustained by muscles varies with
  the type of muscle fiber
  – Swimming tuna use oxidative muscle
  
  • Sustained activity
    – Salmon leaping waterfalls use glycolytic muscle
  • High power but low endurance
  • Leads to lactic acid build-up

Question 6

Muscle use and changes with training

Answer 6

• Type of muscle is related to the activity of that
  muscle
  – Muscle composition (fiber composition) does
  not change
  – Muscle fiber size can change (enlarge)

Question 7

Muscle use and changes with training (cont.)

Answer 7

• Some organisms have
  modifications to allow
  more variable use of
  the same muscle type
  – Insects fuel all
  exercise aerobically
• Have a unique
  tracheal system to
  minimize the
  distance oxygen
  must travel

Question 8

Use of aerobic and anaerobic during exercise

Answer 8

• Maximal aerobic exercise
  – Maximum exercise level that can be fueled
  aerobically
• Submaximal exercise
  – Surplus aerobic exercise capacity during
  exercise
• Supramaximal exercise
  – Exercise at a level surpassing aerobic ability

Question 9

During exercise

Answer 9

• Respiratory and circulatory systems can’t
  deliver oxygen fast enough at the start
  – Demand and supply are not equal
  – Must be made up after exercise ends

Question 10

What is happening during oxygen deficit

Answer 10

– Use O2 stores
– Not aerobic metabolism because cannot get
enough O2
– Use anaerobic metabolism
– Phosphagen stores
* What happens during “Pay as you go”?
* What happens during post-exercise oxygen
consumption?

Question 11

Sources of fuel for ATP generation during exercise
that lasts a long time

Answer 11

• Anaerobic glycolysis
• Phosphagens (creatine or arginine phosphate)
• Aerobic catabolism using glycogen and
  glucose
• Aerobic catabolism using lipids

Question 12

Exercise under hypoxic and anoxic conditions

Answer 12

• During long dives
  – Birds and mammals
  
  • Subdivide the allocation of their oxygen
  • Some parts use anaerobic glycolysis
    – Freshwater turtles
  • Become anoxic
  • Can survive without oxygen
    – Up to 1000X longer than similar vertebrates

Question 13

Oxygen availability and regulation

Answer 13

• Oxygen regulation
  – Steady state aerobic catabolism despite
  fluctuation in environmental oxygen
• Animals require some amount of oxygen
  – What happens when the amount available is
  lower than the minimum required?
  – Oxygen conformity- use all that is available