Muscle Tissue & Skeletal Muscle Notes
Interesting Muscle Facts What is the biggest muscle in your body?
How many muscles do you use to smile? 17
How many muscles do you use to frown? 43
Where is the strongest muscle in the body? In the jaw, it is called the masseter muscle.
NOTES – MUSCLE TISSUE AND THE SKELETAL MUSCLES MUSCLE TISSUE ANATOMY Epimysium outer covering of muscles Fascicle a bundle of muscle fibers
Perimysium each fascicle is covered by the perimysium Endomysium thin covering around each muscle fiber both perimysium & endomysium contain blood vessels and nerve endings
MUSCLE TISSUE – MICROSCOPIC ANATOMY Myofibrils each muscle fiber (muscle cell) contains bundles of myofibrils
made of 2 proteins: 1. ACTIN – the thin one 2. MYOSIN – the thick one Sarcomere formed by the arrangement of actin and myosin
SKELETAL MUSCLE – MICROSCOPIC VIEW
SKELETAL MUSCLE – MICROSCOPIC VIEW – CROSS SECTION
Sarcomere (cont.) A - BAND area where actin & myosin overlap I - BAND area of actin only what gives skeletal muscle its STRIATIONS
Z – Lines are also the boundaries of the sarcomere Z – LINES where I – Bands attach (actin)
Sarcoplasmic Reticulum contains large stores of calcium surrounded by SARCOLEMMA (muscle cell membrane)
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