Skeletal Muscle

Structure

Basic StructureThis stuff is

easy!

1. Each skeletal muscle is an organ composed mainly of skeletal muscle cells and connective tissue

a. Tendons – connect Muscle to Bone

2. Most skeletal muscles extend from one bone across a joint to another bone

a. Muscles PULL!

3. Skeletal Muscle is composed of 3 parts

a. Origini. Attachment to the

bone that REMAINS STATIONARY or fixed when movement occurs

b. Insertioni. Point of attachment

to the bone that moves when a muscle contracts

c. Bodyi. Main part of the

muscle / bulk

4. Tendonsa. Connect Muscle to Bone

i. STRAIN when injured

b. NOT to be confused with a Ligamenti. Connects Bone to Bone at a Joint - SPRAIN

c. Strongi. Some Elasticity

5. Enclosed in synovial tubesa. Lubricant

b. Tendon Sheaths

6. Bursaea. Small synovial-lined sacs containing

synovial fluidi. Located between tendons and bone at joint

ii. Reduce Friction with movement

Microscopic Structure of

Muscle FibersIt really is like String Cheese

1. Contractile cells / FIBERS grouped into bundles

a. Each Fiber is wrapped by the Endomysium

2. Each Bundle is a Fascicle

a. Each Fascicle is wrapped by the Perimysium

b. All bundles are wrapped by the Epimysium

3. The WHOLE Package of muscle is encased by the Fascia an non-elastic protective tissue

4. Fibers contain two types of myofilaments

a. Thicki. Contain the

protein MYOSIN

b. Thini. Contain the

protein ACTIN

5. Basic functional or contractile unit is called a SARCOMERE

6. Sarcomeres separated from each other by dark bands called Z LINES