CH 15 muscle tissue components

hypertrophy

muscle growth from use

addition of structural proteins to muscle fibres, increasing cell diameter

atrophy

decreasing muscle from lack of use

loss of structural proteins from muscles, decreasing muscle mass

sarcopenia

age-related muscular atrophy

list 4 functions of skeletal muscle

• can start/stop body movement

• controls substance movement (swallowing)

• protects internal organs as barrier

• regulates homeostatic temperature (contraction/shivering)

list three “E” qualities of muscle tissues

1. Excitability: neural stimulation sending action potentials

2. Elasticity: stretch/recoil ability

3. Extensibility: ability to extend/lengthen

epimysium

loose irregular connective tissue covering skeletal muscle fibres → maintains structural integrity while muscles move/contract

• separates muscles from other tissues/organs in the area

fascicle

individual bundles of muscle fibres inside each skeletal muscle organized by perimysium

• muscle fibers encased in endomysium

perimysium

connective tissue layer organizing fascicles into bundles

endomysium

connective tissue layer of collagen and reticular fibres that encases each muscle fibre in each fascicle

• contains extracellular fluid and nutrients supporting muscle fiber

periosteum

coats the bone, fuses with ligaments

movement of the skeleton is produced by _____ of the muscle fibers being transferred to the _____, then to the ______ to pull on the ____.

[contraction] [tendon] [periosteum] [bone]

muscle fibres are the term for ____ ____ cells

[skeletal muscle cells]

sarcolemma

plasma membrane of muscle fiberes

sarcoplasm

cytoplasm of muscle fibers

sarcoplasmic reticulum (SR)

smooth ER that stores, releases, retrieves calcium ions

myofilaments

actin (thin) and myosin (thick)

myofibril

organelle running parallel inside the muscle fiber containing sarcomeres

sarcomere

packet of actin, myosin, and troponin+tropomyosin (regulatory proteins) on the myofibrils

• runs from one Z-line to another

the striated appearance of skeletal muscle fibres is due to […]

[the sequence arrangement of actin and myosin from one end of muscle fibre to the other]

the entire muscle fibre cell contracts when […]

[when myofibrils contract]

z-discs/z-lines

where actin (thin) myofilaments anchor to sarcomere

label the individual muscle fibre components