Topic 19 - Types of striated muscles, energy sources of muscle functioning, oxygen debt

Question 1

Words to include in types of striated muscles

Answer 1

• Water
• Proteins
  
  • Structural proteins
  • Soluble proteins
  • Contractile
  • Albumin
  • Enzymes
• ATP
• Creatine phosphate
• Skeletal muscle
• Cardiac muscle
• Smooth muscle
• ATPase type
• SR pump
• Junction / fiber
• T-system
• Muscle AP / neural AP
• Contraction time
• Metabolism
  
  • Mixed
  • Anaerobic
  • Oxidative
• Fatigue
• Fiber length
• Phasic type
  
  • Fast twithc
  • Anaerobe glycolysis
  • White
    
    • M. gastrocnemiu
• Tonic type
  
  • Slow twithc
  • Sustained work
  • Glucose oxidation
  • Red
    
    • M. longimissimus dorsi
• Intermediate type
  
  • Pink
    
    • M. pectoralis
• Dynamic remodeling
  
  • Hyperthrophy
    
    • Fiber hypertrophy
  • Atrophy
    
    • Muscle degradation
• Remodeling (of slow muscles)
  
  • Myoglobin content ↑
  • Mitochindria ↑
  • Oxidative enzyme content of mitochondria ↑
  • Capillarization ↑

Question 2

Words to include in energy soruces of muscle functioning

Answer 2

• ATP
  
  • Contraction
  • Relaxation
• Creatine-phosphate
  
  • Short term energy reserve
  • Intensive contraction
• Anaerobe glycolysis
  
  • Glycogen
    
    • Glycogenolysis
    • Fast movement
  • Glucose
    
    • Long term contaction
  • Lactic acid
    
    • Sarcomere level (ø contraction)
• Oxidative phosphorylation
  
  • Long term muscle activity
  • Red muscles
  • Pyruvate
  • AcCoA
  • ATP resynthesis (slow)

Question 3

Words to include in oxygen debt

Answer 3

• Anaerobe glycolysis
• Resynthesize
• Aerobe conditions
  
  • Oxygen consumption (↑)
• Anaerobe mechanisms
  
  • Replenish glycogen
  • Creatine phosphate
• Oxygen consumption
• Resting
• Working in oxygen-free environment
• Oxygen debt

Question 4

Types of striated muscle

Define striated muscle

Answer 4

• Striated muscle tissue has:
  
  • Sarcomeres
    
    • ​The presence of sarcomeres manifests as a series of bands along the muscle fibers, giving a striated apperance
  • T-tubules
    
    • ​Enables the release of Ca²⁺ from the SR
• Types of striated muscles:
  
  • Cardac muscle
  • Skeletal muscle

Question 5

Chemical composition of muscle tissue

Answer 5

Question 6

Types of striated muscle

What is the difference between striated and smooth muscle?

Answer 6

• Striated muscle tissue have sarcomeres
• Striated muscles are attached to some component of the skeleton
• Striated muscle fibers have a cylindrical shape with blunt ends
  
  • Smooth muscles are spindle-like
• Striated muscles have more mitochondria and contains cells that are multinucleated

Question 7

Types of striated muscles

Classification of muscle fibers

Answer 7

• Fast twithc fibers
  
  • ​Powerful contractions
  • Can cover energy needs by anaerobic glycolysis
  • White or phasic muscles
• Slow twithc fibers
  
  • ​Sustained work
  • Gain energy only from glucose oxidation
  • Red or tonic muscles
• Intermediate type
  
  • ​Pink
  • Fiber types are usually intermixed in mosed of the muscles

1. ATPase type
   
   • ​​Speed of the ATPase activity
2. SR pump
   
   • ​The activity of the ATPase must be followed by the removal of Ca²⁺
3. Junction / fiber
   
   • ​Myoneural junction in phasic fibers:
     
     • ​1 : 1
     • Fiber : Nerve connection ratio
   • A motor nerve fiber splits in many branches
     
     • 25 : 1
     • Fiber : nerve ratio is normal
4. T-system
   
   • ​​The development of a T-sytem can increase contractile speed
5. Muscle AP / neural AP​​
6. Contraction time​
7. Fatigue
8. Fiber length
   
   • ​​The longer the fibers are in a muscle, the more efficient becomes the mechanical movement

Question 8

Types of striated muscle

Training

Answer 8

• Training: dynamic remodeling of muscles

1. Hypertrophy
   
   • ​​The mass of induvidual fibers are increased (fiber hyperthrophy)
   • Increasen in actin and myosin filaments
   • Increase of energy producing enzyme systems
2. Atrophy
   
   • ​During long periods of inactivity, muscle degradation can be seen
   • Some diseases leads to muscle atrophy

Question 9

Types of striated muscles

What happens during remodeling of slow muscles?

Answer 9

↑ Myoglobin content of fibers

↑ Mitochondria

↑ Oxidative enzyme content of mitochondria

↑ Capillarization of the muscle

Question 10

Energy sources of muscle functioning

Give the energy sources

Answer 10

1. ATP
   
   • ​​Contraction and relaxation needs ATP
2. Creatine-phosphate
   
   • ​​Provides energy reserve for short term
   • Intensive contraction
3. Anaerobe glycolysis
   
   • ​​Energy source can be:
     
     • Glycogen
       
       • ​For fast movemet
       • Glycogenolysis
     • Glucose
       
       • ​Long term contraction
   • If more ATP is used than produced = oxygen debt
   • Accumulated lactic acid inhibits contraction at sarcomere level
4. Oxidative phosphorylation​
   
   • Long term muscle activity
   • Red muscles
   • Pyruvate is transformed to AcCoA
   • ATP resynthesis is slow, and contraction is slow
     
     • Therefore the consumption of ATP is not more than the production

Question 11

Oxygen debt

Answer 11

• Muscles that cover most of their energy needs by anaerobic glycolysis during their active functioning resynthesize previously depleted energy stores in rest:
  
  • In this phase resynthesis is going under aerobic conditions
  • Oxygen consumption ↑
• Stores used up by anaerobic mechanisms are resynthesized during rest:
  
  • Muscle can replenish glycogen, creatine-phosphate, etc., by oxygen consumption
• If more ATP is used than produced = oxygen debt