1. The Musculoskeletal System Support, Protection, Movement and Locomotion

2. Functions Motion Maintenance of posture Heat production
Protection of internal organs

3. Origin of muscle tissue
Forms from the mesoderm germ layer
Triploblasts simplest: flatworms
Segmentation  annelids, arthropods, vertebrates

4. Types of muscle tissue Striated Smooth Invertebrate muscles
Skeletal
Attached to bones
Striated and voluntary
Cardiac
Heart wall
Highly branched
Striated and involuntary
Smooth
Walls of hollow internal structures
Nonstriated and involuntary
Striated
Voluntary movements
Longitudinal or circular in shape
Smooth
Involuntary movements
Invertebrate muscles
Vertebrate muscles

5. Muscle action Motion produced by action of muscles on bones  levers
Tendons  attach muscles to bones (e.g. Achilles tendon)
1 fixed point of attachment (origin) and 1 moving point of attachment (insertion)
Fascia  sheets that cover muscles
Muscles work in antagonistic or opposing pairs

6. Organization of skeletal muscles

7. Overview of the Sliding Filament Theory
The muscle fiber is stimulated.
Ca2+ ions are released.
Thin filaments move to middle of sarcomere.
Muscle fiber contracts.
Muscle tension increases.

11. Muscle twitch
Cycle of contraction and relaxation generated from one stimulus
All or none response of muscle fibers
Force Summation
Increasing # and size of fibers contracting
Increasing frequency at which action potentials are sent to muscle fibers

12. Slow and Fast Twitch Fibers
Slow Twitch
More ATP from aerobic respiration
Continuous extended contractions over time
More myoglobin
Fast Twitch
Anaerobic metabolism (creatine phosphate and lactic acid fermentation)
Short bursts of speed
Fatigue quickly

13. Muscle and exercise

15. Cramps Painful sensations caused by contraction/
overshortening of muscles
Causes
Hyperflexion
Inadequate oxygenation
Changes in temperature
Dehydration
Low amount of electrolytes in blood
Treatment
Correct breathing
Increasing intake of water and electrolytes