Biology Forums - Study Force

 :o  I have lost the CD after my computer crashed. I need to submit my lab tonight before midnight (Sunday April 17, 2011).  I need answers and screenshots unless you can magically send me the exe program.

PhysioEX8.0 for A&P - Lab 2 Skeletal Muscle Physiology (p. 17)

 ???

wat questions do you need help with? post them here.

I did attach a word doc with the lab....

but here it what is still missing and I need screen shots for certain areas (indicated)

Activity 2: Determining the Latent Period

Data:    (add in EACH tracing you create here via screen shot or scanning data in; to make a screen shot, press "PrtScr" at the top of your keyboard and then right click in your template exactly where you want to put your screen shot and click "Paste" )

Questions:   ?answer each question; use full sentences; ask instructor if you need help

2-1: How long is the latent period? In other words, how much time elapses before the active force reading moves? ______ msec

2-2: What occurs in the muscle during this apparent lack of activity? (Hint: something IS occurring; see p. 18)


Summary:    

In this Activity, I learned/observed that:  ? write 1-2 sentences on what you observed by doing this experiment – think “big picture”

Activity 3: Investigating Graded Muscle Response to Increased Stimulus Intensity

Data:   (add in EACH tracing you create here via screen shot or scanning data in)

Questions:  ?answer each question; use full sentences; ask instructor if you need help   

3-1: What is the minimal, or threshold stimulus? In other words, when does active force start? ________ V

3-2: What is the maximal stimulus? In other words, when is the stimulus maximized (not the highest it can go but the highest active force you see)? ________V

3-3: How can you explain the increase in force that you observe?

Summary:    

In this Activity, I learned/observed that: ? write 1-2 sentences on what you observed by doing this experiment – think “big picture”

Activity 4: Investigating Treppe

Data:    (add in EACH tracing you create here via screen shot or scanning data in)

Questions:  ?answer each question; use full sentences; ask instructor if you need help

4-1: What happens to force production with each subsequent stimulus?  Force _____________ (increases, decreases, stays the same - choose one) with each subsequent stimulus.

Summary:    

In this Activity, I learned/observed that: ? write 1-2 sentences on what you observed by doing this experiment – think “big picture”

Activity 5: Investigating Wave Summation

Data:    (add in EACH tracing you create here via screen shot or scanning data in)

Questions:  ?answer each question; use full sentences; ask instructor if you need help

5-1: Is the peak force produced in the second contraction greater than that produced by the first stimulus?

5-2: Is the total force production even greater?

5-3: In order to produced smooth, sustained muscle contraction at Active Force = 2 gms, do you think  you will need to increase or decrease the voltage?

5-4: At what voltage were you able to achieve Active Force = 2 gms? ________ V

5-5: How does the frequency of stimulation affect the amount of force generated by the muscle? Hint: Compare the force generated from a single click and from rapidly clicking "Single Stimulus" several times. Increased frequency causes ____________(increased, decreased, the same - choose one) force to be generated by the muscle.

Summary:    

In this Activity, I learned/observed that: ? write 1-2 sentences on what you observed by doing this experiment – think “big picture”

Activity 6: Investigating Fusion Frequency/Tetanus

Data:    (add in EACH tracing you create here via screen shot or scanning data in)

Questions:  ?answer each question; use full sentences; ask instructor if you need help

6-1: Describe the appearance of the tracing. Specifically, discuss the force appearance.

6-2: How do the tracings change as the stimulus rate is increased? Increased stimulation rate causes ___________ (increased, decreased, the same - choose one) active force; this is demonstrated by __________________ (smoother, rougher, the same - choose one) peaks shown on the tracings.

6-3: From your graph, estimate the stimulus rate above which there appears to be no significant increase in force: __________ stimuli/sec

6-4: What stimulus intensity produced smooth (active) force at Force = 2 gms? _______V

6-5: What intensity produced smooth contraction at Force = 3 gms? ________V

6-6: Explain what must happen to the intensity and frequency of the stimulus to achieve smooth contraction at different force levels. Increased stimulation rate creates _________________ (smoother, rougher, the same - choose one) contraction and decreased voltage means that _______________ (more, less, the same - choose one) force is produced.

Summary:    

In this Activity, I learned/observed that: ? write 1-2 sentences on what you observed by doing this experiment – think “big picture”

Activity 7: Investigating Muscle Fatigue

Data:    (add in EACH tracing you create here via screen shot or scanning data in)

 ;)  Added bit of information - I wouldn't normally ask for this amount of information at the last min however my grades are suffering since I had my son in the during this term (almost 3 weeks ago) and I haven't gotten back into the swing - only 2 weeks left and have to pass.

Congrats about your son. I answered activity 2 and 3, I believe, in another post.

Te section 2 & 3 you previously answered didn't seem to match up with the question from the A&P eBook....

How do I post some definintions that would go along with this PhysioEx 8.0 for A&P informaiton?

Hmm, it's because we likely have different versions.

I also need the answers for this review sheets questions but i think we have different version.

The first question in my manual is about:

Electrical stimulation
1. Name each phase of a typical muscle twitch and describe what is happening in each phase
2. How long is the latent period
Describe the chemical changes that are occurring during this period?

If you guys know the answer, pls let me know i will really appreciate it.

Skeletal Muscle Physiology
Assuming a fixed starting length, describe the effect resistance has on the initial velocity of shortening, and explain why is has this effect.

Couldn't find this question, what activity and exercise is this?

Need help with Exercise 2 -Skeletsl Muscle  Physiology due Saturday8/27/011
Details:Physio Lab Experiments  Including:
Single  Stimulus
Multiple Stimulus
Isometric Contraction
Isotonic Contraction

Am working on your questions, I ll post the answers in 2-3 hours.

Ty.

hi,

Sorry I havent been able to finish it off but I did complete it partially till activity 6, and then I got bored. I will pick it up tomorrow Unless I get bored of it again.

Jessica Dallape       
April 16, 2011         
SC145L-8G         
Lab 2 - Skeletal Muscle Physiology (p. 17)

Introduction:     
In this lab, I will study how muscles contract, what makes muscles contract, different types of muscle contraction, and learn about how resistance affects muscle contraction. I will define Key Terms that describe what will occur in the experiments; I will conduct an experiment for each Activity and provide all resulting Data as well as answer Questions from each Activity. I will then provide a short Summary for what I learned in each Activity.

Key Terms:   
Recruitment (or Multiple Motor Unit Summation) (p. 18) - greater number of motor units are present in a muscle and are able to be simultaneously stimulated causing an increase in muscle force
Latent Period (p. 18) - The interval between exposure to an infectious organism or a
carcinogen and the clinical appearance of disease
Isometric  Contraction (or Fixed Length Contraction) (p. 20, 23 in Lab Manual; p. 963 - Hole's)  - A contraction in which muscle tension is increased, but the muscle is not.
Treppe  (or Staircase Effect) (p. 20) - The occurrence of a successive increases  in the extent of contractions following rapid, repeated stimulation of a muscle.
 Wave Summation  (p. 21) - The combination of responses from a motor unit that has had two
or more stimuli applied to it in quick succession.
Tetanus (p. 21) - A state of continuous muscular contraction, especially when induced artificially by rapidly repeated stimuli.
Muscle Fatigue (p . 23) - Muscle fatigue is the repeated, intense use of muscles which leads to a decline in performance.Though the actual mechanism for muscle fatigue appears to involve the leakage of calcium.
Passive Force  (p. 23) - Any movement produced by a force that is external to the muscle or muscle group normally responsible for the movement.
Active Force  (p. 23) - A force due to movement entirely controlled by muscular activity.
Total Force (p. 23) - The process by which multiple or repeated stimuli can produce a response in a nerve, muscle, or other part that one stimulus alone cannot produce.
Isotonic Contraction (p. 25) - Of or involving muscular contraction in which the muscle remains under relatively constant tension while its length changes.

Activity 1: Practicing Generating a Tracing

No Data for This Activity (practice generating tracings)

No Questions For This Activity

Summary:
In this Activity, I learned how to produce a tracing of muscle activity following stimulation.


Activity 2: Determining the Latent Period

Data:    (add in EACH tracing you create here via screen shot or scanning data in; to make a screen shot, press "PrtScr" at the top of your keyboard and then right click in your template exactly where you want to put your screen shot and click "Paste" )

Questions:   ?answer each question; use full sentences; ask instructor if you need help

2-1: How long is the latent period? In other words, how much time elapses before the active force reading moves?
A:___2.2___ msec

2-2: What occurs in the muscle during this apparent lack of activity? (Hint: something IS occurring; see p. 18)
          A: During the latent period of muscle contraction action potential sweeps across the sarcolemma and the sarcoplasmic reticulum releases calcium ions. The muscle fiber does not produce tension during the latent period, because the contraction cycle has yet to begin, Ca++ is being released from the sacroplasmic reticulum and filament movement is taking up slack. This takes approx. 2 milliseconds

 



Summary:    

In this Activity, I learned/observed that:
A: I have learned that when a skeletal muscle is stimulated, there is a short time interval before the muscle starts to contract. During this time interval there are chemical reactions involved in the muscle which helps it to prepare for the contraction.

Activity 3: Investigating Graded Muscle Response to Increased Stimulus Intensity

Data: (add in EACH tracing you create here via screen shot or scanning data in)

Questions:  ?answer each question; use full sentences; ask instructor if you need help   

3-1: What is the minimal, or threshold stimulus? In other words, when does active force start?
A: The minimal or threshold stimulus is the minimum amount of  voltage  required to start a muscle contraction or see an increase in the active force value, which is____0.7___ V for a 75mm length muscle.


3-2: What is the maximal stimulus? In other words, when is the stimulus maximized (not the highest it can go but the highest active force you see)?
A: Maximal stimulus is the voltage at which the active force exerted by the muscle is at its maximum and cannot increase further that that which is ___8.2____V for a 75mm length muscle.

3-3: How can you explain the increase in force that you observe?
A: As the stimulus voltage is increases the active force exerted by the muscle increases to a certain value which depends on the muscle length, after which additional increase in the stimulus voltage will not increase the active force further.

Summary:    

In this Activity, I learned/observed that: A: In this activity I have learnt that a skeletal muscle has a threshold for the stimulus voltage, which changes with the length of a muscle. These threshold levels determine the minimum and maximum amount of voltage required to determine a muscle’s active force values.

Activity 4: Investigating Treppe

Data:    (add in EACH tracing you create here via screen shot or scanning data in)

Questions:  ?answer each question; use full sentences; ask instructor if you need help

4-1: What happens to force production with each subsequent stimulus?
A:  Force increases with each subsequent stimulus.

Summary:    

In this Activity, I learned/observed that
A: For the first few muscle contractions the muscle produces slightly more force than the previous contractions as long as the muscle is allowed to fully relax between stimuli and the stimuli are delivered close together. Treppe is caused due to increased enzyme efficiency and increased calcium levels in the cell.

Activity 5: Investigating Wave Summation

Data:    (add in EACH tracing you create here via screen shot or scanning data in)

Questions:  ?answer each question; use full sentences; ask instructor if you need help

5-1: Is the peak force produced in the second contraction greater than that produced by the first stimulus?
A: Yes the peak force produced in the second contraction is greater than that produced by the first stimulus

5-2: Is the total force production even greater?
A: Yes the total force production even greater

5-3: In order to produced smooth, sustained muscle contraction at Active Force = 2 gms, do you think  you will need to increase or decrease the voltage?
A: In order to produced smooth, sustained muscle contraction at Active Force = 2 gms, voltage should be decreased.
5-4: At what voltage were you able to achieve Active Force = 2 gms?
A: _2.0__ V for a 75mm muscle.

5-5: How does the frequency of stimulation affect the amount of force generated by the muscle? Hint: Compare the force generated from a single click and from rapidly clicking "Single Stimulus" several times.
A: Increased frequency causes __increased___(increased, decreased, the same - choose one) force to be generated by the muscle.

Summary:    

In this Activity, I learned/observed that:
A: I have learnt that when the stimulus frequency given to a muscle is increased when the muscle is already in a partially contracted state, the force that the muscle generates increases.
Activity 6: Investigating Fusion Frequency/Tetanus

Data:    (add in EACH tracing you create here via screen shot or scanning data in)

Questions:  ?answer each question; use full sentences; ask instructor if you need help

6-1: Describe the appearance of the tracing. Specifically, discuss the force appearance.
A: After the muscle reaches a certain force, it forms a suspended wave appearance in the tracing and for each subsequent stimuli rate the force begins to decrease/drop.

6-2: How do the tracings change as the stimulus rate is increased?
A: Increased stimulation rate causes increased active force; this is demonstrated by smoother peaks shown on the tracings.

6-3: From your graph, estimate the stimulus rate above which there appears to be no significant increase in force
A: ___148_______ stimuli/sec for a 75mm length muscle.

6-4: What stimulus intensity produced smooth (active) force at Force = 2 gms? ____1.1___V

6-5: What intensity produced smooth contraction at Force = 3 gms? __1.4______V

This is great :D Thanks for an informative posting.

any chance you were able to finish the rest of the responses? they were very helpful! thanks!

Don't how to get U the screen shots, but I can help with the answers!


7-1: Why does the force begin to decrease with time? Note that a decrease in force indicates muscle fatigue. (Hint: think about what a muscle needs to contract). 
The force began to decrease because there are only a few ATP molecules available for the contraction part in the muscle cells.

7-2: Turning the stimulator off allows a small measure of recovery. The muscle will produce force for a longer period if the stimulator is briefly turned off than if the stimulations were allowed to continue without interruption. Explain why. 
Because when the stimulator is turned off, the muscle is able to rest a moment, allowing it to ATP’s too catch up, which in turn will allow it to continue producing force before the muscle began to fatigue.

7-3: Describe the difference between the current tracing and the myogram generated in step 6.
The current tracing shows rapid muscle fatigue than when the stimulator was turned on and off in step 6.

8-1: What happens to the passive and active forces as the muscle length is increased from 50 mm to 100 mm? Specifically, discuss what the force looks like at particular lengths - at what lengths did the force show large increases or decreases.
Passive force: 
As the muscle length was being increased from 50mm to 100mm, the passive force basically stayed 0.00 until the muscle length reach 80mm.  Once the muscle got to 80mm, the muscle began to show increases in passive force but not much.  Then when the muscle reached 84mm, the muscle began to show larger increases in passive force.   
Active force:
As soon as the first contraction started, the active force began showing large increases and continued to steadily increase until the muscle length got to 75mm, and then the force started to show large decreases as the muscle lengths increased.   
Total force:
As the muscle length is being stretched from 50mm to 100mm, the total force is showing large amounts of increases.  Once the muscle length reaches 76mm the total force starts to quickly decrease, but starts to show large increases again at 94mm causing a dip in the total force.

8-2: Explain the dip in the total force curve. (Hint: Keep in mind you are measuring the sum of active and passive forces). 

I need the answer also!!!

9-1: What do you see happening to the muscle during the flat part of the tracing? Click "Stimulate" to repeat if you wish to see the muscle action again. 
During the flat part of the tracing, the muscle rises from the platform and then falls again.

9-2: Does the force the muscle produces change during the flat part of the tracing (increase, decrease, or stay the same)? 
The force the muscle produces stays the same during the flat part of the tracing.

9-3: Which of the two weights used so far results in the highest initial velocity of shortening?
Weight___1.5__ g
Velocity __0.45____mm/sec

9-4: Repeat step 6 for the remaining two weights:
Weight __1.0___g
Velocity__1.34___ mm/sec

Weight ___2.0__g
Velocity ___0.00__mm/sec

9-5: What does the plot reveal about the relationship between resistance and the initial velocity of shortening? Increased resistance causes __shorter_______________ (shorter, longer, the same - choose one) initial velocity of shortening.

9-6: Describe the relationship between starting length and initial velocity of shortening.
As the starting length of the muscle is increased from 60mm to 90mm, the initial velocity of shortening first increases and then decreases.

MEKAYLA, thanks for sharing this.