Question

1. Every human body has an uncountable number of this basic unit of a muscle known as the: (1 point)

Answer 1

Answer:

The following are the correct answers to each question:

1. Option A, muscle fibers. Skeletal muscle is made up of bundles of individual muscle fibers.
2. Option B, endurance activities. There are two types of muscle fibers; fast-twitch and slow-twitch. Slow-twitch muscle fibers are necessary for aerobic exercises which involve low levels of exertion but with high level of endurance.
3. Option A, a motor unit. A motor unit consists of one neuron and all of the muscle fibers that it innervates.
4. Option D, all or none principle. The all or none principle states that the strength by which a muscle fiber responds to a stimulus is independent of the strength of the stimulus. If that stimulus exceeds the threshold potential, the nerve or muscle fiber will give a complete response; otherwise, there is no response.
5. Option A, striated muscles. It is a muscle tissue in which the contractile fibrils in the cells are aligned in parallel bundles and come in pairs, so that their different regions form stripes visible in a microscope. Muscles of this type are attached to the skeleton by tendons and are under voluntary control.
6. Option C, smooth muscles. It is a muscle tissue in which the contractile fibrils are not highly ordered, occurring in the gut and other internal organs and not under voluntary control.
7. Option B, cardiac muscle. Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscles, with the other two being skeletal and smooth muscles. It is an involuntary, striated muscle that constitutes the main tissue of the walls of the heart.

Answer 2

1:  muscle fibers 
2:  Endurance activities
3:  a motor unit 
4:  All or none principal 
5: Striated muscles
6: Smooth muscles 
7:  Cardiac muscles