summary muscular system (basics)

MUSCULAR SYSTEM
Anatomy muscle
Connective tissue layers (support)

o Epimysium: wrapped around muscle
o Perimysium; wrapped around fascicles in muscle
o Endomysium: wrapped around muscle cells (myocytes in fascicles)



tendon




Anatomy muscle fiber (myocytes)
Plasmalemma / sacrolemma

- Fuses with the tendon (= fibrous cords of connective tissue)
- Surrounds individual muscle fiber = “celmembrane”


Sarcoplasm (cytoplasm)

- Gelatin-like substance
- Fills the spaces within and between myofibrils
- Fluid part of muscle fiber = “cytoplasm”


Transvers tubules (T-tubules)

- Extensions of the plasmalemma
- Are interconnected, pass through muscle fiber
- Receives nerve impulses and transmit them to the individual myofibrills
- Provide pathways from outside fiber to its interior  substances can enter
fiber and waste products can leave the fibers

, Sarcoplasmic reticulum

- Network of tubules, within muscle fiber
- Storage side for calcium, essential for muscle contraction




Myofibrils

- Small fibers made up of sacromeres, thick and thin filaments

Sacromeres
- Basic functional unit myofibril and basic contractile unit
- Striped pattern of skeletal muscles
- Dark regions, known as A-bands
 Lighter center, H-zone or H-band only visible when myofibrill is
relaxed
 Dark line in middle of H-zone, M-line

- Light regions known as I-bands
 Interrupted by dark stripe, Z-disk or Z-line (boundaries between
sarcomeres)