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

3. 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

6. 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

9. The sarcomere Made of protein myofilaments Thick: myosin
Thin: actin, troponin, tropomyosin
These filaments slide over one another during muscle contraction

10. 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.)

11. The beginning of muscle contraction

12. 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

14. 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

15. 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?

16. 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 Gehrig’s disease
motor neurons degenerate and die leading to loss of voluntary muscle movement