8/17/2019 Laporan Faal Act 3

1/6

Exercise 2: Skeletal Muscle Physiology: Activity 3: The Effect of Stimulus Frequency on Skeletal Muscle Contraction Lab

Report

Pre-lab Quiz Results

You scored 100% by answering 4 out of 4 questions correctly.

1. During a single  twitch of a skeletal muscle

You correctly answered: b. maximal force is never achieved.

2. When a skeletal muscle is repetitively stimulated, twitches can overlap each other and result in a stronger muscle

contraction than a stand-alone twitch. This phenomenon is known as

You correctly answered: c. wave summation.

3. Wave summation is achieved by

You correctly answered: a. increasing the stimulus frequency (the rate of stimulus delivery to the muscle).

4. Wave summation increases the force produced in the muscle. Another way to increase the force produced by a muscle

is to

You correctly answered: d. increase the number of activated motor units.

010/10/15 page 1

8/17/2019 Laporan Faal Act 3

2/6

010/10/15 page 2

Experiment Results

Predict Question:

Predict Question 1: As the stimulus frequency increases, what will happen to the muscle force generated with each

successive stimulus? Will there be a limit to this response?

Your answer : b. As the stimulus frequency increases, the muscle force generated by each successive stimulus will

increase. There will be a limit to this increase.

Predict Question 2: In order to produce sustained muscle contractions with an active force value of 5.2 grams, do you thinkyou will need to increase the stimulus voltage?

Your answer : b. no

Stop & Think Questions:

Was there any change in the force generated by the muscle during the second stimulated twitch?

You correctly answered: c. Yes, the second twitch generated more muscle force.

Is the total muscle force generated by the higher frequency stimulation greater than the force generated in previous

stimulations?

You correctly answered: a. Yes, it is greater than the previous stimulations.

Does the force generated by the muscle change with each additional stimulus?

You correctly answered: b. As the stimulus frequency increased, the muscle tension generated by each successive stimulu

also increased, and a limiting maximum value was observed.

Experiment Data:

Voltage Length Stimulus Active Force Passive Force Total Forc

8.5 75 Single 1.83 0.00 1.83

8.5 75 Multiple 2.56 0.00 2.56

8.5 75 Multiple 2.85 0.00 2.85

8.5 75 Multiple 4.38 0.00 4.3810 75 Multiple 4.69 0.00 4.69

8.5 75 Multiple 5.31 0.00 5.31

8/17/2019 Laporan Faal Act 3

3/6

010/10/15 page 3

8/17/2019 Laporan Faal Act 3

4/6

010/10/15 page 4

8/17/2019 Laporan Faal Act 3

5/6

010/10/15 page 5

Post-lab Quiz Results

You scored 100% by answering 4 out of 4 questions correctly.

1. Which of the following is not  one of the ways that the body can increase the force produced by a skeletal muscle?

You correctly answered: d. application of higher voltages to the whole muscle

2. When a muscle receives a stimulus frequency that causes non-overlapping  twitches to follow each other closely in time

such that the peak tension of each twitch rises in a stepwise fashion up to a plateau value, the result is known asYou correctly answered: c. treppe.

3. In this experiment the isolated skeletal muscle was repetitively stimulated such that individual twitches overlapped with

each other and resulted in a stronger muscle contraction than a standalone twitch. This phenomenon is known as

You correctly answered: c. wave summation.

4. Wave summation is achieved by

You correctly answered: a. increasing the rate of stimulus delivery (frequency) to the muscle.

8/17/2019 Laporan Faal Act 3

6/6

010/10/15 page 6

Review Sheet Results

1. What is the difference between stimulus intensity and stimulus frequency?

Your answer:

-intensitas stimulus adalah semakin besar jumlah serat otot yang berkontraksi, semakin besar tegangan total otot.

-frekuensi stimulus adalah ketegangan sebuah otot bergantung pada jumlah dari serat otot yang berkontraksi, tetapi juga

bergantung pada tegangan yang dibentuk oleh tiap-tiap serat otot yang berkontraksi tersebut.

2. In this experiment you observed the effect of stimulating the isolated skeletal muscle multiple times in a short period wit

complete relaxation between the stimuli. Describe the force of contraction with each subsequent stimulus. Are these results

called treppe or wave summation?

Your answer:

kontraksi dimulai oleh stimulus pertama karena mekanisme kontraktil tidak memiliki periode refractory stimulasi berulang

sebelum relaksasi. memproduksi aktivasi tambahan dan sebuah respon terhadap kontraksi yang terjadi. fenomena ini

dikenal sebagai kontraksi sumasi.

3. How did the frequency of stimulation affect the amount of force generated by the isolated skeletal muscle when the

frequency of stimulation was increased such that the muscle twitches did not  fully relax between subsequent stimuli? Arethese results called treppe or wave summation? How well did the results compare with your prediction?

Your answer:

ketika sebuah serat otot skelet distimulasi pada ratio 20-30 kali/detik dapat menyebabkan relaksasi sebagian diantara

stimuli. hal ini disebut treppe.

4. To achieve an active force of 5.2 g, did you have to increase the stimulus voltage above 8.5 volts? If not, how did you

achieve an active force of 5.2 g? How well did the results compare with your prediction?

Your answer:

tidak. Dengan cara otot dirangsang sedemikian cepatnya dan terus menerus sehingga tidak mendapatkan kesempatan

berelaksasi sempurna, maka timbullah kontraksi menetap dengan kekuatan maksimal yang disebut tetanus

5. Compare and contrast frequency-dependent wave summation with motor unit recruitment (previously observed by

increasing the stimulus voltage). How are they similar? How was each achieved in the experiment? Explain how each is

achieved in vivo .

Your answer:

tidak sama. dari hasil percobaan 3 diperoleh hasil bahwa dengan multiple stimulus pada otot akan terus meningkatkan

active force sampai diperoleh tegangan maksimum dengan stimulus voltage tetap. rekrutment unit motorik adalah

kemampuan otot untuk berkontraksi lebih kuat dengan cara memperbanyak serat otot yang disarafi oleh sebuah neuron

motorik yang mampu bekerja secara harmonis.