Overview
a network of fluid filled membrane-enclosed tubules that store calcium ions required for muscle contraction
What is the sarcoplasmic reticulum?
elongated, cylindrical cells arranged parallel to one another
The main component to thin filaments anchored to the Z disks
What is the protein actin?
zig-zagging zones of dense material
What are Z disks?
The wasting away of muscles
What is muscular atrophy?
forceful, repetitive muscular activity, such as strength training, causes this disorder
What is muscular hypertrophy?
a plasma membrane that covers each muscle fiber
The two protein molecules, aside from actin, in the thin filaments
What are tropomyosin and troponin?
extends the entire length of thick filaments
What is the A Band?
the atrophy that occurs when muscles are unused
What is disuse atrophy?
muscle fibers being replaced by fibrous connective tissue and muscle shrinking to one quarter of its original size
tunnel-like extensions of the sarcolemma that pass through the muscle fibers transversely
What are transverse tubules?
the shape that individual actin molecules join to form
What is helix?
contains only the thick filaments
What is the H zone?
disrupted or cut nerve supply to a muscle
What is denervation atrophy?
the 3 components of thin filaments
What is actin, tropomyosin, and troponin?
the two types of protein filaments present in each myofibril
What are thin and thick filaments?
found in actin molecule for a myosin head
What is the myosin-binding site?
composed of thin filaments
What is the I Band?
increase in the diameter of muscle fibers due to overproduction of structures of skeletal muscle (ex. excess mitochondria)
What is muscular hypertrophy?
the structural organization of a skeletal muscle from macroscopic to microscopic
stores oxygen until needed to generate ATP
What is myoglobin?
cover the myosin-binding sites on actin in relaxed muscle fibers
What are tropomyosin and troponin?
band with thick filaments in its center and overlapping thin and thick filaments at each end
What is progressive loss of myofibrils?