BMS unit 4

All the muscle fibers under the control of a single motor axon are referred to as

a motor unit

all of these proteins are thin filaments:

actin troponin tropomyosin

A skeletal muscle fiber (cell) contains a single nucleus. true or false

false

Which of the following statements is true concerning calcium ions?

in smooth. muscle, it binds with calmodulin

Which of the following best describes the role of Ca2+ in muscle contraction?

it binds to troponin , moving tropomyosin, so that myosin heads can bind to actin

The typical skeletal muscle fiber contains several components that facilitate the production of ATP. what are they

mitochondria myoglobin glycogen

Place the organizational level of muscle tissue in order, beginning with the entire muscle and ending with the smallest component.

muscle fascicle muscle fiber myofibril myofilaments

thick filaments have

myosin and myosin heads

The amount of additional oxygen that must be inhaled following exercise to restore pre-exercise conditions is called

oxygen debt

the muscle cell membrane is called

sarcolemma

The contractile unit of a myofibril is called the

sarcomere

An action potential causes calcium ions to diffuse from the ________ into the ________.

sarcoplasmic reticulum ; sarcoplasm

At the ends of muscles, the connective tissues merge to form a __________, which attaches the muscle to other structures.

tendon

The specialized region of the sarcolemma that has folds and indentations to increase the membrane surface area covered by the synaptic knob is the

the motor end plate

The component of a muscle fiber that quickly transports a muscle impulse from the sarcolemma throughout the entire muscle fiber is called the

transverse tubules

Rising sarcoplasmic calcium levels results in contraction in both smooth muscle fibers and skeletal muscle fibers. true or false

true

Smooth muscle contraction and skeletal muscle contraction both involve thin filaments sliding over the thick filaments. true or false

true

The area between the presynaptic nerve cell and the postsynaptic muscle cell is termed the synaptic cleft. True or False?

true

A ________ is defined as a single, brief contraction period and then relaxation period of a skeletal muscle in response to a single stimulation.

twitch