Chapter 10 Assessments

Nearly all muscles of the body develop from an early embryonic layer of cells called the mesoderm.

True

A treatment for myasthenia gravis is pyridostigmine which stops ACh from being broken down. Which does pyridostigmine inhibit?

AChE

Which ion is required for exocytosis of ACh?

Ca+2

Stretching is most effective at reducing injury and promoting greater flexibility if it is done over the course of many weeks, and always when the muscle is cold (before beginning to exercise).

False

Current Attempt in Progress Muscular tissue has several important properties, such as electrical excitability. Another property of muscular tissue is that it is able to stretch, and return to its original size and shape. Which property of muscular tissue is this?

Elasticity

To delay the onset of muscle fatigue, not all the motor units in a muscle will contract at the same time. Some will remain relaxed while others are contracting. If the contraction continues, and greater force is needed, more motor units will be recruited.

True

Warm up exercise before stretching or strenuous muscle activity prevents injury because tissues stretch best when gentle force is applied at elevated temperatures.

True

Which list of organs contains smooth muscle tissue?

both blood vessels, stomach, esophagus and bladder, uterus, small intestine

Autonomic motor neurons regulate:

both smooth and cardiac muscle

What type of skeletal muscle fiber would an Olympic quality weight lifter specifically be developing during training, to enhance his or her weight lifting power?

fast glycolytic fibers

As one ages, the presence of slow oxidative fibers ___.

increases

This structure is unique to cardiac muscle cells, and allows individual cells to be firmly attached to each other (to provide mechanical strength during contraction), and also allow the action potential to spread rapidly through the cardiac muscle tissue, so that contractions are smooth and coordinated.

intercalated discs

When oxygen is plentiful inside a skeletal muscle cell, what happens to the pyruvic acid that is formed during glycolysis?

it diffuses into mitochondria to be broken down to generate ATP

Which of the following is not a function of skeletal muscle tissue?

moving food through the small intestine

A small amount of muscle tension and muscle definition (the appearance of muscle beneath the skin) is present even in a relaxed muscle. A person who is physically fit due to regular exercise, will have more of this characteristic of muscle tissue than someone who is not fit. What is this characteristic?

muscle tone

Which of the following molecules found in skeletal muscle cells binds oxygen that can later be used during aerobic metabolism to help generate ATP?

myoglobin

The site where a somatic motor neuron releases acetylcholine to stimulate a skeletal muscle fiber is called the

neuromuscular junction

Skeletal muscle is covered, surrounded and protected by various layers of connective tissue. Which layer of connective tissue would surround a bundle of muscle fibers (muscle cells)?

perimysium

If you are an endurance athlete, you especially rely on which type of skeletal muscle fiber to perform your sport?

slow oxidative fibers

Which type of muscle tissue is involuntary (can't be consciously controlled)?

smooth muscle and cardiac muscle

Depending on how specialized a type of muscle tissue is, the muscle fibers or cells of that tissue will have varied abilities to regenerate (healing and production of new cells). What type of muscle tissue has the greatest ability to regenerate?

smooth muscle cells have the greatest ability to regenerate

Smooth muscle fibers do not have striations like skeletal and cardiac muscle cells do. This is because:

smooth muscle fibers contain thin and thick filaments, as well as intermediate filaments, but none of them are arranged in sarcomeres

The contractile organelle of skeletal muscle fibers is

the myofibril