biol 3410 10/24

The point at which a neuron communicates with a muscle fiber is called the __________.

neuromuscular junction.

The neurotransmitter released at the neuromuscular junction is __________.

Acetylcholine.

An __________ is generated in the muscle cell after sodium ions enter through the acetylcholine receptor.

action potential.

Calcium ions enter the cytosol from the __________ during excitation-contraction coupling.

sarcoplasmic reticulum.

The interaction between myosin and actin filaments during contraction is facilitated by __________.

calcium.

When ATP is used by myosin during muscle contraction, it is necessary for the __________ of myosin from the active site on actin.

detachment.

A __________ contraction is the response of a motor unit when stimulated.

twitch.

The optimal length of a sarcomere for generating maximum tension is referred to as the __________ ____ __________ relationship.

length-tension relationship.

The three main pathways for ATP production in muscles are creatine phosphate pathway, anaerobic respiration, and __________ respiration.

aerobic.

During the latent period of muscle contraction, __________ is building up in the cytosol due to calcium release.

calcium.

During relaxation of skeletal muscle, calcium is transported back into the __________.

sarcoplasmic reticulum.

Motor units consist of one motor neuron and all the __________ it innervates.

muscle fibers.

The phosphagen system provides __________ ATP quickly but is limited in duration.

short-term.

Lactic acid is a by-product of __________ respiration.

anaerobic.

In excitation-contraction coupling, the electrical signal leads to calcium release, which triggers __________ contraction.

mechanical.

The __________ is the structure that contains the cell bodies of motor neurons in the spinal cord.

spinal cord.

In muscle contraction, the power stroke occurs as myosin heads pull actin filaments toward the __________ line.

M line.

Tension developed in a muscle fiber depends on the __________ of the muscle fiber.

length.

During muscle contraction, ATP hydrolysis is essential for the __________ of each myosin head.

recovery.

Smooth, useful movements are produced through controlled activation of __________ units in muscles.

motor.