Troy High Labs Online: How Do Your Muscles Work?
INTRODUCTION:
Much of the work of the body depends on the contraction of skeletal
muscles. In this experiment you will first observe the characteristics of
muscle contraction and then will investigate the effects of two factors -
temperature and fatigue - on the action of your muscles.
MATERIALS:
dishpan of water
narrow strip of paper which will fit around upper arm
ice or snow
rubber ball or clothespin
timer (clock, watch, or stop watch)
PROCEDURE:
The following exercises will help you understand what happens to your
muscles when they contract.
Muscle Action
1. Place your fingers along the angle of your jaw just in front of your
ear. Grit your teeth and observe what happens to the hardness of the
muscles in your cheek.
2. With the thumb and little finger of one hand, span the opposite arm's
biceps (front muscle of the upper arm) from the elbow to as close to the
shoulder as possible. Bend the arm and observe the change in the length of
the muscle.
3. Wrap a strip of paper around your upper arm and mark the circumference
of your arm on the paper. Clench your fist tightly and mark the new
circumference on the paper. Observe what happens to the circumference of
the muscle.
INTRODUCTION:
Much of the work of the body depends on the contraction of skeletal
muscles. In this experiment you will first observe the characteristics of
muscle contraction and then will investigate the effects of two factors -
temperature and fatigue - on the action of your muscles.
MATERIALS:
dishpan of water
narrow strip of paper which will fit around upper arm
ice or snow
rubber ball or clothespin
timer (clock, watch, or stop watch)
PROCEDURE:
The following exercises will help you understand what happens to your
muscles when they contract.
Muscle Action
1. Place your fingers along the angle of your jaw just in front of your
ear. Grit your teeth and observe what happens to the hardness of the
muscles in your cheek.
2. With the thumb and little finger of one hand, span the opposite arm's
biceps (front muscle of the upper arm) from the elbow to as close to the
shoulder as possible. Bend the arm and observe the change in the length of
the muscle.
3. Wrap a strip of paper around your upper arm and mark the circumference
of your arm on the paper. Clench your fist tightly and mark the new
circumference on the paper. Observe what happens to the circumference of
the muscle.
Effect of Temperature on Muscle Action
1. Count the number of times you can make a fist in 20 seconds. Start withyour hand completely outstretched and make a tight fist each time. Do it
as rapidly as you can. Record the count in Figure 1.
2. Now submerge your hand in a dishpan of water to which has been added
snow or ice so that the temperature is near the freezing point. Leave your
hand in the water for one full minute.
3. Remove your hand and immediately count how
Picture: Clenching my fist before and after submerging hand in ice water.
many forceful fists you can
make in 20 seconds. Record in Figure 1.
make in 20 seconds. Record in Figure 1.
Figure 1: Effect of Temperature on Muscle Action
Temperature Number of Fists
Temperature Number of Fists
Normal 31
Ice Water 13
Ice Water 13
Effect of Fatigue on Muscle Action1. Count how many times you can tightly squeeze a rubber ball in your hand
in 20 seconds. Record in Figure 2.
2. Repeat the squeezing nine more times and record results. Do not rest
between trials.
(An alternative procedure which works well is to open and close a
clothespin with the thumb and index finger while the other fingers are held
out straight.)
Picture: Squeezing a ball to find out what would happen after hand is fatigued.
Figure 2: Effect of Fatigue on muscle action
Trial # of Squeezes in 20 seconds
1 47
2 50
3 43
4 36
5 29
6 27
7 21
8 14
9 12
10 11
ANALYSIS OF DATA:
1. What are the three changes you observed in a muscle while it is working (contracted)?
The three changes I observed in muscle while it was working were the muscle became harder, larger, and became shorter and longer in length.
2. What effect did the cold temperature have on the action of your hand muscles? Explain.
The effect that the cold temperature had on the action of my hand muscles was that it slowed down the muscle’s contraction, the muscles became much more tense, and when I squeezed my hand, I had slight burning sensations in my lower palm. The reason why these reactions happened to my hand muscle, because as my hand was immersed in the ice cold water, my muscles were already contracting. They were already contracting to maintain homeostasis within the body, by speeding up the chemical processes in the cells from the reaction of the cold water. As I continued to clench my fist after I pulled my hand out of the water, the cells within the body had to work even harder to maintain equilibrium.
Attempts Number
3. What effect did fatigue have on the action of your hand muscles? Explain.
The effect that fatigue had on the action of my hand muscles was that it causes the muscles to expand and contract at a slower rate. And, as the squeezing of the ball continued, without rest, it became harder for my muscles to work at a constant rate. The reason why this occurred is due to cellular respiration. When oxygen is lacking in the cells, the normal process of cellular respiration leads to fermentation, where the cells work harder, but more quickly, to make energy. Then, the formation of lactate occurs, creating buildup, and fatigue of muscles.
Trial # of Squeezes in 20 seconds
1 47
2 50
3 43
4 36
5 29
6 27
7 21
8 14
9 12
10 11
ANALYSIS OF DATA:
1. What are the three changes you observed in a muscle while it is working (contracted)?
The three changes I observed in muscle while it was working were the muscle became harder, larger, and became shorter and longer in length.
2. What effect did the cold temperature have on the action of your hand muscles? Explain.
The effect that the cold temperature had on the action of my hand muscles was that it slowed down the muscle’s contraction, the muscles became much more tense, and when I squeezed my hand, I had slight burning sensations in my lower palm. The reason why these reactions happened to my hand muscle, because as my hand was immersed in the ice cold water, my muscles were already contracting. They were already contracting to maintain homeostasis within the body, by speeding up the chemical processes in the cells from the reaction of the cold water. As I continued to clench my fist after I pulled my hand out of the water, the cells within the body had to work even harder to maintain equilibrium.
Attempts Number
3. What effect did fatigue have on the action of your hand muscles? Explain.
The effect that fatigue had on the action of my hand muscles was that it causes the muscles to expand and contract at a slower rate. And, as the squeezing of the ball continued, without rest, it became harder for my muscles to work at a constant rate. The reason why this occurred is due to cellular respiration. When oxygen is lacking in the cells, the normal process of cellular respiration leads to fermentation, where the cells work harder, but more quickly, to make energy. Then, the formation of lactate occurs, creating buildup, and fatigue of muscles.
Our muscles are always at work. And, it is due to our muscles within in our body that we are able to perform particular movements. In the experiement of “How Do Your Muscles Work”, provided by Troy High Labs Online, was used to determine how muscles react to particular situations. The first major part of the experiement displayed the reaction of the hand muscles when they are immersed in ice water, and then contracted for a short amount of time afterwards. The second major part of the lab displayed the reaction of the hand muscles when they are fatigued, by squeezing a ball continuously for an amount of time. The reasoning behind the particular reactions that occurred to the hand muscles in the two different experiments can be explained on a cellular level. During the clenching of the fist after being submerged Picture: How muscle contraction occurs
in ice water, the muscles were much more tense and contraction slowed down. The cells within the body were reacting to the presence of cold by the sensory receptors in the peripheral nervous system. The central nervous system responded by creating more energy to be expended to contract the muscle, in order to maintain homeostasis in the body. While squeezing the ball continuously, the muscles contracted at a slower rate, due to fatigue. The cells within the body were lacking oxygen in order to fulfill the normal process of cellular respiration. This lead to fermentation, which created lactate buildup, and the end result of muscle exhaustion. Overall, this lab gives a hands-on understanding to what actually happens to muscles in given circumstances.
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