1. Muscle Tissue & Skeletal Muscle Notes

2. Interesting Muscle Facts What is the biggest muscle in your body?

3. How many muscles do you use to smile? 17

4. How many muscles do you use to frown? 43

5. Where is the strongest muscle in the body? In the jaw, it is called the masseter muscle.

6. NOTES – MUSCLE TISSUE AND THE SKELETAL MUSCLES MUSCLE TISSUE ANATOMY Epimysium outer covering of muscles Fascicle a bundle of muscle fibers

7. Perimysium each fascicle is covered by the perimysium Endomysium thin covering around each muscle fiber both perimysium & endomysium contain blood vessels and nerve endings

8. MUSCLE TISSUE – MICROSCOPIC ANATOMY Myofibrils each muscle fiber (muscle cell) contains bundles of myofibrils

9. made of 2 proteins: 1. ACTIN – the thin one 2. MYOSIN – the thick one Sarcomere formed by the arrangement of actin and myosin

11. SKELETAL MUSCLE – MICROSCOPIC VIEW

12. SKELETAL MUSCLE – MICROSCOPIC VIEW – CROSS SECTION

13. Sarcomere (cont.) A - BAND area where actin & myosin overlap I - BAND area of actin only what gives skeletal muscle its STRIATIONS

14. Z – Lines are also the boundaries of the sarcomere Z – LINES where I – Bands attach (actin)

15. Sarcoplasmic Reticulum contains large stores of calcium surrounded by SARCOLEMMA (muscle cell membrane)

16. T - Tubules aka: Transverse Tubules function to help the electrical impulse for muscle contraction reach the cell’s interior also allow calcium to reach myofibrils T-TUBULE