1. EQ: How do our muscles in our body contract?
Muscle System
EQ: How do our muscles in our body contract?

2. Root Words

3. 3 Kinds of Muscle
Skeletal
Smooth (stomach, intestine)
Cardiac

4. Skeletal
Composed of fibers and filaments that contract and relaxed when stimulated

5. Motor Neurons
Neurons that controls the contraction of skeletal muscles

6. Synapse
The connection point where the neuron communicates with the tissue

8. Acetylcholine
The neurotransmitter that stimulates contraction. Synthesized in the cytoplasm of motor neuron

9. Composition
Myofibrils- Muscle threads that lie parallel to one another (2 kinds of myofilaments)
Myosin- Thick protein filament
Actin- Thin protein filament

13. Cross Bridge
Little hands that extend from Myosin to “grab” the actin. This causes the contraction

14. Sliding Filament Model
Thick and thin filaments (myosin and actin) do not change length. Rather, they slide past one another

18. Sarcoplasmic Reticulum
Specialized cell that regulates the calcium ion concentration in the cytoplasm of muscle cells

20. Calcium Muscle contraction
1. Action Potential runs through neurons
2. Sends message through Transverse Tubules (T-tubes)
3. Release Calcium ions through Sarcoplasmic Reticulum
4. Calcium release ions for ATP contraction

22. Sliding filament theory
ATP binds to a myosin head, which is released from an actin filament
The myosin head attaches to an actin binding site with the help of Calcium

23. Sarcomere
The striations formed with the repeating pattern of Myosin and Actin

24. Sarcomere
During contraction, the filaments do not get shorter, but the Sarcomere will shorten

25. Creatine Phosphate

26. Left Side Activity
Draw a picture of a muscle that is at rest and then draw it again when it is contracted. Explain what is going on.