Study guide

1
Study guide

• What are the three types of muscle tissue, their
  structure and location?
• What are the functions of the muscular system?
• How are skeletal muscles and muscle fibers
  structured from largest to smallest?
• What are the steps of skeletal muscle
  contraction?
• How do skeletal muscle cells acquire ATP for
  contraction?
• Distinguish between slow and fast twitch fibers.
• What are some common muscular disorders?

2
Review 3 types of muscle tissue
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What are the functions of skeletal muscles?

• Support
• Movement
• Homeostasis-How do skeletal muscles help us
  maintain body temperature?
• Protection internal organs and stabilize joints

4
How are skeletal muscles arranged?

• Attachments
• Tendon
• Origin
• Insertion
• Action
• Antagonistic
• Synergistic

5
An example of muscle arrangement
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Examples of how skeletal muscles are named

• Size gluteus maximus, vastus lateralis
• Shape deltoid, trapezius
• Location frontalis, tibialis anterior
• Direction of muscle fiber rectus abdominus,
  external oblique
• Attachment brachioradialis
• Number of attachments biceps brachii
• Action extensor digitorum

7
Skeletal Muscle Structure

• Terminology for cell structure
• plasma membrane ______________________
• Cytoplasm___________________
• ER_______________ ___________________
• Muscle fascicle (bundle of fibers)
• Muscle fiber
• Myofibrils
• Sarcomeres consisting of myofilaments

8
Visualizing muscle structure
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The sarcomere

• Made of protein myofilaments
• Thick myosin
• Thin actin, troponin, tropomyosin
• These filaments slide over one another during
  muscle contraction

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The beginning of muscle contraction The sliding
filament model

• 1. What type of neuron carries information toward
  the muscle?
• 2. What is released from the pre-synaptic cell?
• 3. What does it bind to? (This binding will
  cause calcium to be released from the SR.)

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The beginning of muscle contraction
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Muscle contraction continued

• 4. Released calcium combines with troponin
• 5. Myosin binding sites exposed
• 6. Cross-bridges form
• 7. ATP binds and power stroke occurs

13
Visualizing the role of calcium and myosin in
muscle contraction
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What are the sources of ATP for muscle
contraction?

• Limited amounts of ATP are stored in muscle
  fibers
• Creatine phosphate pathway (CP) fastest way to
  acquire ATP but only sustains a cell for seconds
  builds up when a muscle is resting
• Fermentation fast-acting but results in lactate
  build up
• Cellular respiration (aerobic) not an immediate
  source of ATP but the best long term source

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Muscle fibers come in two forms

• Fast-twitch fibers
• rely on CP and fermentation (anaerobic)
• Designed for strength
• Light in color
• Few mitochondria
• Fewer blood vessels

• Slow-twitch fibers
• Rely on aerobic respiration
• Designed for endurance
• Dark in color
• Many mitochondria
• Many blood vessels

Where in the body would you have examples of each
of these?
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Types of muscle fibers
17
Muscular diseases

• Fibromyalgia chronic achy muscles that is not
  well understood
• Muscular dystrophy group of genetic disorders
  in which muscles progressively degenerate and
  weaken
• Myasthenia gravis immune system attacks ACh
  receptor and weakens muscles of the face, neck
  and extremities-What kind of disorder is this?

18
Amyotrophic lateral sclerosis (ALS)

• commonly known as Lou Gehrigs disease
• motor neurons degenerate and die leading to loss
  of voluntary muscle movement