Muscles

Formed by supporting proteins holding thick filaments together in the center of the H zone.

M line

12) Smaller structures within myofibrils.

Filaments

Serves as storage form of glucose; can be broken down and used to synthesize ATP.

Glycogen

Center of the A band; contains only thick filaments.

H zone

Contains only thin filaments.

I band

Entire length of the thick filament; contains area of overlap with thin filament.

A bands

connects a Z disc to the M line of a sarcomere, helping stabilize the position of the thick filament.

titin

Proteins that are considered structural proteins.

titin alfa actine, myomesin, nebulin, dystophin

Proteins that are considered regulatory proteins.

tropomoysin and troponin

this protein is a component of the thin filament that will cover the myosin-binding sites on the actin molecules.

tropomyosin

this protein is a component of the thin filament and is where calcium ions will bind to during skeletal muscle contraction.

troponin

A fiber is categorized as slow or fast depending on how rapidly the ATPase in its myosin heads hydrolyze ATP

true

Fast glycolytic fibers have low myoglobin content, few blood capillaries, few mitochondria, and appear white in color.

true

Fast oxidative- glycolytic fibers are fast-twitch fibers adapted for intense movements of short duration like weight lifting or throwing a ball.

true

Fast oxidative- glycolytic fibers have a high intracellular glycogen level, which allows them to generate ATP by aerobic respiration.

true

Skeletal muscle fibers that have a high myoglobin content are termed red muscle fibers

true

Slow oxidative fibers are smallest in diameter and are the least powerful type of muscle fibers.

true

Slow oxidative fibers generate ATP mainly by aerobic respiration

true

Contractile element of the skeletal muscle fiber; containing thick and thin filaments

Myofibril

Red, oxygen binding protein that is only found in the muscle; stores oxygen until it is needed by mitochondria for ATP.

Myoglobin

storage center for calcium in relaxed muscle.

Sarcoplasmic reticulum

Invaginations of the sarcolemma; filled with extracellular fluid.

T tubules

2) Narrow, plate shaped regions of dense protein.

Z discs

main component of the thin filament that has an active myosin-binding site.

actin

present in the Z discs, it will attach to actin and titin molecules.

alpha actinin

Ability of muscle to contract forcefully when adequately stimulated

contractility

links thin filaments of the sarcomere to integral membrane proteins in the sarcolemma. This might help transmit the tension generated by sarcomeres to tendons.

dystrophin

Ability of muscle to return to its original length and shape after contraction or extension

elasticity

Ability to respond to certain stimuli by producing action potentials

electrical excitability

Match each muscle property with its correct definition. Ability of muscle to stretch without being damaged

externsibility

Fast glycolytic fibers are intermediate in diameter and have a high resistance to fatigue

false

Match the terms to their definition/function Plasma membrane of a muscle fiber.

sacromere

Repeating units of a myofibril.

sacromere

Surrounded by the sarcolemma; the cytoplasm of the muscle fiber.

sacroplasm

Proteins that are considered contractile proteins.

myosin & actin

wraps around the entire length of each thin filament. It also helps to anchor thin filaments to Z discs in addition to regulating the length of thin filaments during development.

nebulin

Formed by transverse tubules and two terminal cisternae.

Triad

forms the M line of the sarcomere. It also binds to titin molecules and connects adjacent thick filaments to one another.

myomesin

makes up the thick filaments. It consists of two heads and a tail.

myosin