Question 1

Many athletes engage in resistance training to increase the speed at which they can perform motions required for their sports. Which statement best explains the effect of resistance training on speed?

Accepted Answer

Resistance training increases the power output of muscles, enhancing their ability to move loads quickly, which can improve speed in athletic motions.

Question 2

Resistance training of skeletal muscle would normally result in an increase in the

Accepted Answer

Resistance training typically increases the muscle's maximum isometric force by enhancing muscle fiber size and neural adaptations, rather than affecting oxygen consumption, shortening velocity, or capillary number.

Question 3

Experiments that combine endurance and resistance training indicate that

Accepted Answer

Resistance and endurance training can simultaneously produce some of their characteristic effects on skeletal muscle, as they target different adaptations within the muscle fibers.

Question 4

In skeletal muscle, endurance exercise

Accepted Answer

Endurance exercise increases VEGF (vascular endothelial growth factor) levels, which promotes angiogenesis, resulting in a greater number of capillaries in skeletal muscle.

Question 5

Endurance exercise generates signals in muscle cells, such as

Accepted Answer

VEGF is a growth factor that is produced in response to hypoxia. It is involved in the formation of new blood vessels, which is necessary for the delivery of oxygen and nutrients to muscles during endurance exercise.

Question 6

Endurance training produces the greatest percentage increase in expression of genes encoding

Accepted Answer

Endurance training enhances the oxidative capacity of muscles, leading to an increased expression of genes encoding mitochondrial enzymes like succinate dehydrogenase, which is crucial for aerobic energy production.

Question 7

Refer to the figure shown.
 According to the data in the figure, a single bout of endurance exercise

Accepted Answer

The answer of Refer to the figure shown.
 According to...

Question 8

A single bout of exercise increases VEGF mRNA less in a trained muscle than in an untrained muscle. The most plausible explanation for this difference is that trained muscle has more

Accepted Answer

Trained muscles have more capillaries, which improves oxygen delivery and reduces the need for increased VEGF mRNA expression during exercise.

Question 9

In skeletal muscle cells, endurance exercise training typically produces

Accepted Answer

Endurance exercise training enhances the oxidative capacity of skeletal muscle, leading to increased mitochondrial content and enzyme activity, such as citrate synthase, which is a marker of mitochondrial density and function.

Question 10

Increases in mitochondrial number and capillary number

Accepted Answer

Mitochondria are the powerhouses of the cell, and capillaries are the smallest blood vessels that deliver oxygen to the cells. Increasing the number of mitochondria and capillaries allows the muscle cells to use more oxygen per unit time, which increases the power of the muscle.

Question 11

Endurance training increases the amounts of both glycogen and lipid stored in muscle cells. This most directly increases the

Accepted Answer

Endurance training enhances the storage of glycogen and lipids, which are energy sources, allowing muscle cells to perform work for longer periods before depleting their fuel reserves.

Question 12

Refer to the figure shown.
 The figure illustrates a part of the typical response of skeletal muscle to

Accepted Answer

The answer of Refer to the figure shown.
 The figure...

Question 13

Bob has been sedentary for several years. As a New Year's resolution, he starts an intense exercise program, but after three months he stops exercising completely. What was the likely effect of the program on his heart mass while he was exercising, and what is the most likely outcome a year later?

Accepted Answer

During the exercise program, Bob's heart mass likely increased due to the demands of intense exercise. However, after stopping the exercise, his heart mass likely decreased back to its previous size due to the lack of continued physical activity.

Question 14

Burmese pythons are a uniquely useful model for studies of cardiac hypertrophy because their heart(s)

Accepted Answer

Burmese pythons' hearts increase in size very rapidly in response to feeding, making them a useful model for studying cardiac hypertrophy.

Question 15

Refer to the figure showing the changes in heart mass of Burmese pythons 3 days after feeding (DPF), infusion with plasma from fed or fasted snakes, or infusion with a solution of bovine serum albumin (BSA) with or without three specific fatty acids (FA) found in blood of fed snakes.
 According to the figure, feeding increases heart mass primarily through

Accepted Answer

The answer of Refer to the figure showing the changes...

Question 16

Refer to the figure shown.
 What is the likely treatment in this figure?

Accepted Answer

The answer of Refer to the figure shown.
 What is...

Question 17

Refer to the figure shown.
 What best explains the results for the experimental group of mice on the right of the figure?

Accepted Answer

The answer of Refer to the figure shown.
 What best...

Question 18

Which statement about muscle atrophy is true?

Accepted Answer

Muscle atrophy involves the breakdown of muscle proteins, releasing amino acids that can be used by other systems in the body.

Question 19

Experiments involving microgravity can be used to study the cellular processes involved in

Accepted Answer

Microgravity conditions, such as those experienced in space, can lead to muscle atrophy due to the lack of gravitational forces that normally stimulate muscle maintenance and growth on Earth.

Question 20

Atrophy of muscles due to disuse is accompanied by a shift in fiber type from _______ fibers to _______ fibers.

Accepted Answer

Muscle atrophy due to disuse typically involves a shift from slower, more oxidative fibers (Type I) to faster, more glycolytic fibers (Type II), as the muscles adapt to reduced activity levels.

Quiz 21: Movement and Muscle at Work: Plasticity in Response to Use and Disuse