Pre-lab Quiz Questions

____ attach skeletal muscle to the periosteum of bones

Tendons

A motor unit consists of:

a motor neuron and all of the muscle cells it innervates

During the ____ phase of a muscle twitch, chemical changes - such as the release of calcium - arre occurring intracellularly as the muscle prepares for contraction.

Latent

An action potential in a motor neuron triggers the release of ____.

Acetylcholine

True or False: When a weak muscle contraction occurs, each motor unit still develop its maximum tension even though fewer motor units are activated.

True

True or False: During wave summation, muscle twitches follow each other closely, resulting in a step-like increase in force, so that each successive twitch peaks slightly higher than the one before, resulting in a staircase effect.

False; (treppe)

The smallest stimulus required to induce an action potential in a muscle fiber’s plasma membrane is known as the

Threshold voltage

Muscles do not shorten even though they are actively contracting during a/an _____ contraction.

Isometric

Flow rate in a pipe is ____ proportional to the pipe’s resistance

Inversely

(Flow = pressure/resistance)

Total blood flow is proportional to cardiac output, the….

amount of blood the heart pumps per minute

True or false: The longer the blood vessel length, the greater the resistance.

True

Blood vessel radius is controlled by….

smooth muscle contraction or relaxation within the blood vessels

The more viscous a fluid, the ___ resistance it has to flow.

more

The volume remaining in the ventricles at the end of diastole, immediately before cardiac contraction is called….

End diastolic volume

____ occurs as the heart chambers relax and fill with blood.

Diastole

In the human body, the heart beats about ____ strokes per minute.

60-100

A condition that can lead to heart disease ____ is a result of plaque buildup in the arteries.

Atherosclerosis