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.

An individual muscle fiber is     .

a.one long muscle cells

b. a special type of neutral

c.many short muscle cells grouped together

An increase in skeletal muscle size, resulting in increased strength is known as

a.atrophy

b.hyperplasia .

c.hyperthrrophy

Jamal and Stelios 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 the concentration of lactate in their blood over the course of their normal workouts.

The following charts present the results of the study and show the percent of lactate concentration in each man's blood over the course of their workouts, 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 man. 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 man, 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.

Jamal's Lactate Concentration in the Blood (Purple points, diamond symbol)
Duration of exercise (Minutes)	0	2	4	6	8	10
Lactate concentration in the blood (Percent)	0	5	10	10	15	20

Stelios's Lactate Concentration in the Blood (Green points, triangle symbol)
Duration of exercise (Minutes)	0	2	4	6	8	10
Lactate concentration in the blood (Percent)	0	15	25	35	45	50

JamalStelios024681050403020100Lactate concentration in the blood (Percent)Duration of exercise (Minutes)

Which man is doing a workout that primarily involves aerobic exercise?

a.Stelios

b.Jamal

Answer 1

1. An individual muscle fiber are one long muscle cells

2. An increase in skeletal muscle size, resulting in increased strength is known as hypertrophy . Hypertrophy is increase in the size of cells .

3. Graph :

4 O 5 10 15 2o d5 lactate comcentration in blad Tuesday 16 (136-229) Week 20 1ot 6+ 4+ + 0 5 10 1IS 20 as 30 35 40 45 50 latate cmcntratim in blal uration f ererse Duration exer cise

4. The man who is doing a workout that primarily involves aerobic exercise is Jamal because his lactate concentration is less . Lactic acid is produced when muscles release energy for contraction by anaerobic respiration.