1. Muscular system
Anatomy & Physiology

2. Functions Movement, pumping/transport Breathing Posture
Produce heat, regulate body temperature
Protection,(of organs, stabilize joints, etc.)

4. Muscle Types
Skeletal- voluntary (bones, face), over 400, long cells, many nuclei, striated
Cardiac- involuntary (heart and blood vessels), strongest, 1 nuclei per cell, some striations with gap junctions
Smooth- involuntary (intestines, internal organs), slow and smooth, 1 nuclei per cell, no striations

6. Muscle Contraction All or None!
Opposites contract! Muscles work in pairs
Bicep bends at the elbow (relaxed) → tricep straightens the arm (contracted)
muscle contraction animation video

7. Sarcomere = contractile unit

8. Muscle contraction
Actin (thin) filaments, with myosin, are responsible for cell movements 
Myosin (thick) “molecular motor”—a protein that converts chemical energy (ATP) to mechanical energy, (force and movement)
Need Ca++ ions AND ATP to contract
Acetylcholine

10. Types of Muscles
Slow Twitch- red fibers, oxygen storage, can build over time, used for aerobic exercise, long distance running
Fast Twitch- white fibers, used for short burst of energy, born with a certain amount, sprinters
Intermediate- most common, mixture of red and white

11. Naming Muscles Location Vastus lateralis/medialis Shape Deltoid
Size Gluteus maximus
Direction of fibers Oblique, rectus abdominus or femoris
Number of origins Triceps, biceps
Location of attachments Sternocleidomastoid
Action Adductors/abductors

12. Muscles comprise approx. 45% of our body weight
600+ muscles in the body
Approx. 640
Muscles comprise approx. 45% of our body weight
Smallest muscle = stapedius in ear
Largest muscle = gluteus maximus
Most active muscles are in the eye
Over 100,000 movements per day