Muscular System

Skeletal muscle contraction is controlled by _____ neurons

motor

Elasticity

The ability of a material to bounce back after being disturbed

oxygen debt

The amount of additional oxygen that must be inhaled in order to restore pre-exercise levels is called oxygen

thick filament

composed of myosin

In a muscle, the perimysium is composed of what type of connective tissue?

dense irregular

fast glycolytic fibers

contract quickly, have fast myosin ATPase, and are easily fatigued; anaerobic; sprinters

fast oxidative fibers

contract quickly, have fast myosin ATPases, and have moderate resistance to fatigue; aerobic; walking

slow oxidative fibers

contract slowly, have slow acting myosin ATPases, and are fatigue resistant; most efficient; marathon

myofibrils

cylindrical organelles specialized for contraction

Sarcoplasm is another term for skeletal muscle ______.

cytoplasm

In an isometric contraction, the muscle ______ body movement.

does not produce

actin

double-stranded contractile protein

tropomyosin

double-stranded regulatory protein

A skeletal muscle cell is also called a muscle _________

fiber

The sarcoplasm of a skeletal muscle fiber contains hundreds to thousands of long, cylindrical structures called ___________ that extend the length of the cell.

myofibrils

Muscle fibers contain cylindrical structures called myofibrils, which are composed of ______.

myofilaments

Myofibrils are made of ______.

myofilaments

resting muscle tone

relaxed muscles are not completely relaxed and soft. bc they have some background tension

The ___________ filament theory explains how muscle fibers shorten during contraction.

sliding

Epimysium

surrounds entire muscle; most superficial CT layer of muscle tissue

latent period

there is no tension

In a muscle cell at rest, the myosin heads of a thick filament point ______ the sarcomere.

toward the ends of

Calcium ions bind to what protein in a thin myofilament?

troponin

If the sarcoplasm of a muscle cell is flooded with calcium ions, to which protein will they bind?

troponin

True or false: A single myofibril runs the length of the muscle fiber.

true

Each myosin protein molecule in a thick filament consists of ______ strands.

two

Thick filaments are about ______ the diameter of thin filaments.

two times

The endomysium is composed of what type of connective tissue?

areolar

Smooth muscle is found where in the respiratory system?

around the bronchioles

The long tails of the myosin molecules in the thick filaments point toward the ______ of the filament.

center

thin filament

composed of actin, troponin, and tropomyosin

During the development of skeletal muscle cells, some myoblasts do not fuse and instead become ______ cells.

satellite

If a skeletal muscle is injured, surrounding ______ cells may be stimulated to differentiate and assist in its repair and regeneration.

satellite

Summation

A "step-wise" increase in the force of contraction of a single muscle fiber or single motor unit due to repeated stimulation

muscle twitch

A single contraction and relaxation of a muscle fiber

excitiability

Ability of muscles to respond to a stimulus

A muscle fiber is what level of organization in the body?

Cellular

Perimysium

Connective tissue surrounding a fascicle; middle CT layer of muscle tissue

In a thin filament, individual G-actin molecules are strung together to form ______.

F-actin

Myofibrils

Microscopic protein filaments that make up muscle cells.

isometric contraction

Muscle contracts but there is no movement, muscle stays the same length. ex: gripping a cup. holding a position

Function of skeletal muscle

Posture Voluntary movement Temperature regulation

Endomysium

Surrounds individual muscle fibers; innermost layer of CT in muscle

muscle tension

The force generated when a skeletal muscle is stimulated to contract

T/F: Smooth muscle cells retains their mitotic ability.

True

Extensibility

ability to be stretched

Contractability

ability to shorten

bundles of muscle fibers.

fascicles

muscle fatigue

inability to contract and produce tension

muscle recruitment

increase in the # of motor units being used to increase strength of contraction

caveolae

indentations in sarcolemma of smooth musc; may act like T tubules

sarcolemma

plasma membrane of a muscle fiber (cell)

The plasma membrane of a skeletal muscle fiber is called the

sarcolemma