Question

1. A closer look - Muscles and their role in health and energy needs of athletes

Skeletal muscles, which move bones, consist of cells fused into long fibers. These muscle fibers can increase in size when contracted, which is what happens as a result of some exercise. This animation shows the structure of vertebrate skeletal muscles. It starts at a large scale, showing the muscles of a human upper arm, and then gradually zooms in to smaller and smaller levels, labeling each structure along the way. Watch the animation and then answer the question that follows.

The subsections of a myofibril that perform muscle contraction are called     .

a.muscle fiber

b.skeletal muscle

c.sarcomers

The increase in volume of the muscle fibers due to the enlargement of its components is referred to as     .

a.hyperthrophy

b.hyperplasia

c.atrophy

Janis and Terese are friends who both enjoy exercise. They are a similar height and weight, and both are in good shape, but they have different workout activities. One does primarily aerobic exercise, and the other does primarily anaerobic exercise. They both enroll in a study that measures how much oxygen they inhale over the course of their normal workouts.

The following charts present the results of the study and show how much oxygen each woman inhaled over the course of her workout, measured at two-minute intervals.

On the following graph, use the points indicated in the charts to graph the results of the study for each woman. Click and drag the points on the right-hand side of the graph onto the grid of the graph; line segments will automatically connect the points. Remember to plot from left to right. There are 6 points for each woman, so when you are done, there should be 12 total points on the graph. Look at the pattern the points make, and then answer the question that follows.

Janis's Oxygen Consumption (Blue points, circle symbol)
Duration of exercise (Minutes)	0	2	4	6	8	10
Oxygen consumption (Liters per minute)	1	1	1.5	1.5	2	2

Terese's Oxygen Consumption (Orange points, square symbol)
Duration of exercise (Minutes)	0	2	4	6	8	10
Oxygen consumption (Liters per minute)	1	1.5	2.5	4	4.5	4.5

JanisTerese0246810543210Oxygen consumption (Liters per minute)Duration of exercise (Minutes)

Which woman is doing a workout that primarily involves anaerobic exercise?

Janis

Terese

Answer 1

3. Graph :1.The subsections of a myofibril that perform muscle contraction are called sarcomers. Sarcomere is the functional unit of striated muscles .

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2. The increase in volume of the muscle fibers due to the enlargement of its components is referred to as hypertrophy . Hypertrophy is the increase in cell size while hyperplasia is increase in number of cells.

4. Janis is doing a workout that primarily involves anaerobic exercise because she is consuming less oxygen than Terese during exercise .