1. Chapter 8: Muscular System
Anatomy & Physiology 1
Pages

2. Ch. 8 Wordbytes Calat- = something inserted Erg- = work
Hyper- = over, more
Inter- = between
Laten- = hidden
Myo- = muscle
Sarco- = flesh
Syn- = together
Tetan- = stiff
-troph = well fed

3. 8.1 Introduction All movements require muscles
Muscles organs composed of specialized cells that use the chemical energy stored in nutrients to contract
Muscular actions also:
Provide muscle tone
Propel body fluids and food
Generate the heartbeat
Distribute heat

4. Benefits of weight training:
Resistance (weight) training can increase the ratio of muscle to fat in our bodies
Benefits of weight training:
Muscle burns calories 3x faster than fat = a lean body is more energetically efficient
Weight-lifting increases muscle tone and bone density; lowers blood pressure; decreases the risk of developing arthritis, osteoporosis, and diabetes; improves self-esteem; lowers sick days

5. Three types of muscles:
Skeletal
Smooth
Cardiac

6. 8.2 Structure of Skeletal Muscle
Skeletal muscle = organ of skeletal system
Composed of skeletal muscle tissue, nervous tissue, blood, and other connective tissue

7. A. Connective Tissue Coverings
Fascia layers of fibrous connective tissue that separate an individual skeletal muscle from adjacent muscles and hold it in position (fig. 8.1)
Surrounds each muscle
May project to form a tendon
Fibers in tendon could intertwine with bone periosteum, attaching muscle to bone
May form aponeuroses broad fibrous sheets that attach to bone or coverings of adjacent muscles (figs & 8.19)

8. 2. Epimysium layer of connective tissue that surrounds a skeletal muscle 3. Perimysium layers of connective tissue that extend inward from the epimysium and separate the muscle tissue into small compartments 4. Fasicles bundles of skeletal muscle fibers found in perimysium 5. Endomysium thin covering found around each muscle fiber in a fasicle

9. Many blood vessels and nerves pass through layers
Layers of connective tissue enclose and separate all parts of a skeletal muscle
This allows all parts to move independently
Many blood vessels and nerves pass through layers

11. B. Skeletal Muscle Fibers
Skeletal muscle fiber single cell that contracts in response to stimulation then relaxes when stimulation ends
Each fiber is a thin, elongated cylinder with rounded ends
Cell membrane = sarcolemma
Cytoplasm = sarcoplasm; contains many small nuclei , mitochondria, & myofibrils

12. Sarcomeres repeating pattern of units of muscle fibers
Myofibrils help with muscle contraction. They contain 2 filaments that produce the bands (striations):
Myosin thick
Actin thin
Sarcomeres repeating pattern of units of muscle fibers

13. 2. Striation pattern has 2 parts: a
2. Striation pattern has 2 parts: a. I bands light bands composed of thin actin filaments directly attached to Z lines b. A bands dark bands composed of thick myosin filaments overlapping thin actin filaments i. H zone region of thick filaments ii. M line thickening 3. Sarcomere extends from one Z line to the next (figs. 8.2 and 8.3)

14. 4. Sarcoplasmic reticulum membranous network of channels and tubules of a muscle fiber 5. Transverse tubules (T tubules) membranous channels that extend inward from a muscle fiber membrane *The sarcoplasmic reticulum and transverse tubules activate the muscle contraction mechanism when the fiber is stimulated

15. Got muscles?