1. The Muscular System

2. Muscular System Bell Ringer 1. List the three types of muscle tissue.
2. What are the functions of the muscular system?
3. List one other system that assists the muscular system. Explain how it contributes to the muscular system.

3. The Muscular System
Muscles are responsible for all types of body movement
Three basic muscle types are found in the body
Skeletal muscle
Cardiac muscle
Smooth muscle

4. Characteristics of Muscles
Skeletal and smooth muscle cells are elongated (muscle cell = muscle fiber)
Contraction of muscles is due to the movement of microfilaments
All muscles share some terminology
Prefixes myo and mys refer to “muscle”
Prefix sarco refers to “flesh”

5. Comparison of Skeletal, Cardiac, and Smooth Muscles
Table 6.1 (1 of 2)

6. Comparison of Skeletal, Cardiac, and Smooth Muscles
Table 6.1 (2 of 2)

7. Skeletal Muscle Characteristics
Most are attached by tendons to bones
Cells are multinucleate
Striated—have visible banding
Voluntary—subject to conscious control

8. Skeletal Muscle Functions
Produce movement
Maintain posture
Stabilize joints
Generate heat

9. Skeletal Muscle Attachments
Sites of muscle attachment
Bones
Cartilages
Connective tissue coverings

10. Connective Tissue Wrappings of Skeletal Muscle
Cells are surrounded and bundled by connective tissue
Endomysium—encloses a single muscle fiber
Perimysium—wraps around a fascicle (bundle) of muscle fibers
Epimysium—covers the entire skeletal muscle
Fascia—on the outside of the epimysium

11. Connective Tissue Wrappings of Skeletal Muscle
Figure 6.1

12. Microscopic Anatomy of Skeletal Muscle
Figure 6.3a

13. Microscopic Anatomy of Skeletal Muscle
Figure 6.3b

14. Microscopic Anatomy of Skeletal Muscle
Sarcolemma—specialized plasma membrane
Myofibrils—long organelles inside muscle cell
Sarcoplasmic reticulum—specialized smooth endoplasmic reticulum

15. Bell Ringer 1. What is another name for a muscle cell?
2. _______ are specialized organelles within a muscle cell.
3. Which muscle type(s) have involuntary control?
4. This muscle tissue has very long, cylindrical cells, many nucleli, and obvious striations.

16. Microscopic Anatomy of Skeletal Muscle
Sarcomere—contractile unit of a muscle fiber
Myofibrils are aligned to give distinct bands
I band
Light band
Contains only thin filaments
Actin- a protein anchored to the z-line

17. Microscopic Anatomy of Skeletal Muscle
2. A band
dark band
Thick filaments
myosin filaments-a protein
Has ATPase enzymes
Myosin filaments have heads (extensions, or cross bridges)

18. Microscopic Anatomy of Skeletal Muscle
Figure 6.3c

19. Microscopic Anatomy of Skeletal Muscle
Figure 6.3d

20. Microscopic Anatomy of Skeletal Muscle
Myosin and actin overlap somewhat
At rest, there is a bare zone that lacks actin filaments called the H zone

21. The Nerve Stimulus and Action Potential
Skeletal muscles must be stimulated by a motor neuron (nerve cell) to contract
Motor unit—one motor neuron and all the skeletal muscle cells stimulated by that neuron

22. The Nerve Stimulus and Action Potential
Figure 6.4a

23. The Nerve Stimulus and Action Potential
Figure 6.4b

24. The Nerve Stimulus and Action Potential
Figure 6.5a