1. Muscles

2. Muscle Overview
The three types of muscle tissue are skeletal, cardiac, and smooth
These types differ in structure, location, function, and means of activation
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InterActive Physiology ®:
Anatomy Review: Skeletal Muscle Tissue, page 3

4. Muscle Images

7. Sarcomere surrounded by sarcoplasmic reticulum

10. sarcomere contraction
animation myofilament contraction__
sliding-filament-theory

12. Sliding Filament Theory
Order the following events in sequence to explain the contraction of skeletal muscle.
____ Ca+2 binds to troponin/tropomyosin (regulatory proteins) which opens myosin binding sites on actin.
____ As ADP and P leave the myosin head, it swivels forward pulling the actin filament toward the center of the sarcomere. The sarcomere shortens.
____ An action potential moving through the sarcolemma (what is this?) stimulates release of Ca+2 from the sarcoplasmic reticulum.(what is this?)
____ Myosin heads (activated by the breakdown of ATP) bind to exposed sites on the actin filament.
____ ATP binds to the myosin head and it relaxes, falling away from the actin filament. 
 _____ Cycle repeats until Ca2+ or ATP are withdrawn.

14. Events at Neuromuscular Junction

18. Events at Neuromuscular Junction
Action potential in the nerve is activated
Ca2+ runs into the nerve
Ach is released into the synaptic cleft
Ach binds to receptors on the muscle
Na runs into the muscle
Action potential runs across the muscle and into the T tubules
Enzymes break Ach into Acetic Acid and Choline

20. Anatomy and Physiology
How a muscle contracts - Neuromuscular Junction/Sliding Filament Theory
View the following websites to consolidate your understanding of the events at the neuromuscular junction and the sliding filament theory of muscle contraction. :

24. Do Now – Muscle #1
Describe the structure and function of the three types of muscle tissue.
Draw sarcomere from a skeletal muscle cell-show the arrangement of the thin and thick filaments and label the sections of the sarcomere.

25. Muscle Contraction
View the following websites to consolidate your understanding of the events at the neuromuscular junction and the sliding filament theory of muscle contraction.
Neuromuscular junction:
Inside the muscle fiber: