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.)
• what gives skeletal muscle its
STRIATIONS
• A - BAND
• area where actin & myosin overlap
• I - BAND
• area of actin only
• Z – LINES
• where I – Bands attach (actin)
• Z – Lines are also the
boundaries of the sarcomere
• Sarcoplasmic
Reticulum
• surrounded by SARCOLEMMA
(muscle cell membrane)
• contains large stores of calcium
• T - Tubules
• aka: Transverse Tubules
T-TUBULE
• function to help the electrical
impulse for muscle contraction reach
the cell’s interior
• also allow calcium to reach
myofibrils