Anatomy

thin filaments

Cross bridges are created when myosin heads bind to blank

Acetylcholinesterase

Enzyme that breaks down acetylcholine

synaptic celft

Gao between the axon terminals and the plasma membrane of a neighboring muscle cell

Bind to receptors in the sarcolemma of the muscle cell

In order to excite a muscle cell, acetycholine must ____.

Contractility

Muscle tissue has the ability to shorten when adequetly stimulated, a characteristic, known as blank

sarcoplasmic reticulum

The blank is an organelle that wraps and surrounds the myofibril and stores calcium

True

The effect of the neurotransmitter on the muscle cell membrane is so temporarily modify its permeability of ions such as Na+ and K+

synaptic cleft

The gap between the axon terminal of a motor neuron and the sarcolemma of a skeletal muscle cell is called the blank

synaptic cleft

The gap between the motor neuron and the muscle fiber it supplies as the neuromuscular junction is called the blank

cross bridges

The heads of the myosin myofilaments are called ________ when they link the thick and thin filaments together during skeletal muscle contraction.

a sliding of thin filaments past thick filaments

The mechanical force of contraction is generated by what?

True

The neurotransmitter used by the nervous system to activate skeletal muscle cells is acetylcholine

Calcium ions

The sarcoplasmic reticulum stores the chemical

True

The sarcoplasmic reticulum wraps like a sleeve around the myofibril and stores and releases calcium

False

Thick filaments are made of protein called actin

True

When a muscle fiber contracts, the I band diminish in size, the h zonez disappear, and the A bands move closer together but do not diminish in length

Z discs

When a skeletal muscle is fully contracted, the blank are closer to the thick filaments

Sarcomere

Which of the following can actually shorten during a muscle contraction?

Acetylcholine causes temporary permeability to sodium

Which of these events must occur first to trigger the skeletal muscle to generate an action potential and contract?

thick filaments

Which one of the following is composed of myosin protein?

calcium triggers the binding of myosin to actin

Why are calcium ions necessary for skeletal muscle contraction?

motor unit

A motor neuron and all of the skeletal muscle cells it stimulates are termed a blank

False

A muscle twitch results when the muscle is stimulated so rapidly that no evidence of relaxation is seen

False

A neuromuscular junction consist of one neuron and all the skeletal muscles it stimulates

The contractile unit between two z discs

A sarcomere is:

The muscle twitch is a brief but jerky movement, which the tetanic contraction is prolonged and continuous

A skeletal muscle twitch differs from a tetanic contraction in that blank

Fused, or complete, tetanus

A smooth, sustained contraction is called ________.

A neurotransmitter that stimulates skeletal muscle

Acetylcholine is blank

sarcoplasmic reticulum

An elaborate and specialized network of membranes in skeletal muscle cells that function in calcium storage is the blank

action potential

Electric current that travels the length of the muscle

Sodium ions

Chemical that enters a muscle cell upon excitation

actin filaments

During skeletal muscle contraction, myosin heads attach to binding sites associated with ________.

Axon terminals of the motor neuron

Neurotransmitters are released upon stimulation from a nerve impulse by the blank

Motor unit

One neuron and all the skeletal muscles it stimulates is known as a blank

Acetylcholine

Specific neurotransmitter that stimulates skeletal muscle cells