Included with:
Lab Equipment Required: Description: In this experiment, you will use a displacement transducer to determine how weight affects the shortening of a frog muscle. Weight influences the time that a muscle has to shorten, the speed at which the muscle shortens, the distance that the muscle shortens or moves the weight, and the amount of work the muscle completes. You will also compare the difference between: afterloading, supporting the weight before contraction; and preloading, hanging the weight on the muscle without support before contraction.
Goals
1. Students will dissect a frog leg to extract the gastrocnemius muscle of the lower limb. 2. Students will assemble the equipment needed to be able to stimulate the muscle and record muscle twitch. 3. Students will understand the correlation between the stimulus, the muscle twitch amplitude, and the effect of weight on muscle contractions. 4. Students will test afterloading, supporting the weight before contraction; and preloading, hanging the weight on the muscle without support before the contraction. 5. Students will continue to be successful at using the LabScribe software to move cursors, analyze data, record data to the Journal, and add functions to the Analysis window.
Outcomes
Students who have successfully completed this exercise will: 1. be able to successfully excise the gastrocnemius muscle of a frog’s leg. 2. have a better understanding of electrical stimulation of the muscle and the equipment used to perform such stimulation. 3. gain an understanding of muscle stimulation and contraction (twitch) and how they relate to each other. 4. record muscle twitches from the gastrocnemius, test a variety of hypotheses and reach scientific conclusions 5. have used the functions available in the Analysis window to determine values necessary for this exercise. 6. feel comfortable transferring data to the Journal and interpreting that data to answer questions about their recordings.
Included with: 
Lab Equipment Required: 
Description: Most skeletal muscles are composed of some combination of the different twitch-type fibers. Interestingly, a motor neuron makes only one synapse on each of their target fibers, and the muscle fibers innervated by a motor neuron are all of the same type. Therefore, stimulation of a particular motor neuron will create a contraction of only one muscle fiber type; this property is used by the brain to recruit different muscle fibers into a contraction. A motor unit is composed of only one type of muscle fiber and recruitment allows the increase in individual motor units. Activity in descending tracts excites the spinal motor neurons; but, the size of the cell bodies and the activation thresholds of these neurons are different. motor neurons that supply weak, slow, oxidative fibers have the lowest threshold; those innervating fast, intermediate-strength oxidative fibers have higher thresholds; and those that supply the fast, strong, glycolytic fibers have the highest thresholds. In this way increasing the amount of activity descending from the brain activates progressively more motor neurons, and more of the stronger muscle fibers, into the response.
This will be simulated in the following experiment by slowly increasing the voltage applied directly to the muscle to recruit more muscle fibers into the contraction. In addition, the amount of contraction is dependent upon stimulus frequency.
Goals
1. Students will dissect a frog leg to extract the gastrocnemius muscle of the lower limb. 2. Students will assemble the equipment needed to be able to stimulate the muscle and record muscle twitch. 3. Students will understand the correlation between the stimulus, muscle twitch, and the strength of the stimulation on muscle contraction. 4. Students will test summation and tetanus by repeatedly stimulating the muscle. 5. Students will continue to be successful at using the LabScribe software to move cursors, analyze data, record data to the Journal, and add functions to the Analysis window.
Outcomes
Students who have successfully completed this exercise will:
1. be able to successfully excise the gastrocnemius muscle of a frog’s leg.
2. have a better understanding of electrical stimulation of the muscle and the equipment used to perform such stimulation.
3. gain an understanding of muscle stimulation and contraction (twitch) and how they relate to each other.
4. successfully record muscle twitches from the gastrocnemius and correlate the reactions to stimulation to summation and tetanus.
5. have used the functions available in the Analysis window to determine values necessary for this exercise.
6. feel comfortable transferring data to the Journal and interpreting that data to answer questions about their recordings. Included with:
Lab Equipment Required: Description: In this laboratory exercise, students will use a force transducer to monitor the contractility of the frog heart as it is subjected to various imposed conditions, such as: the effect of adding Epinephrine and Acetylcholine to change the heart rate of the exposed heart; the effect of cold temperature on cardiac muscle activity; the effect of electrical stimulation on the refractory period of the heart; and, the effect of interrupting the conduction path between the atria and the AV node with a ligature.
Goals
1. Students will dissect a frog to expose the heart. 2. Students will assemble the equipment needed to be able to stimulate the heart and will record cardiac contractions. 3. Students will understand the correlation between exogenous stimulus and heart muscle response. 4. Students will gather data corresponding to normal heart rhythms. 5. Students will test different parameters with regard to cardiac muscle function: ◦ cold temperature. ◦ epinephrine. ◦ atropine. ◦ isolation of the ventricle. 6. Students will continue to be successful at using the LabScribe software to move cursors, analyze data, record data to the Journal, and add functions to the Analysis window.
Outcomes
Students who have successfully completed this exercise will: 1. be able to successfully isolate the frog heart. 2. have a better understanding of electrical stimulation of the heart muscle and the equipment used to perform such stimulation. 3. gain an understanding of normal cardiac muscle contraction. 4. stimulate and record cardiac muscle contractions to test a variety of hypotheses and reach scientific conclusions. 5. have used the functions available in the Analysis window to determine values necessary for this exercise. 6. feel comfortable transferring data to the Journal and interpreting that data to answer questions about their recordings.
Included with:
Lab Equipment Required: Description: The purpose of this experiment is to demonstrate some of the contractile properties of smooth muscle using an isolated rat uterus: spontaneous contractile activity, the effect of stretching the muscle, and the effects of various agonists on the frequency and the degree of contraction.
Goals
1. Students will dissect a female rat to excise the uterus to be able to examine smooth muscle contractions. 2. Students will assemble the equipment needed to be able to record smooth muscle contractions. 3. Students will gather data corresponding to normal rhythmic smooth muscle contractions. 4. Students will test different parameters with regard to uterine muscle function: ◦ methergine. ◦ acetylcholine. ◦ atropine. ◦ epinephrine. ◦ stretch and tension. 5. Students will continue to be successful at using the LabScribe software to move cursors, analyze data, record data to the Journal, and add functions to the Analysis window.
Outcomes
Students who have successfully completed this exercise will: 1. be able to successfully isolate the rat uterus. 2. activate and record uterine muscle contractions to test a variety of hypotheses and reach scientific conclusions. 3. gain an understanding of rhythmic smooth muscle contractions. 4. have used the functions available in the Analysis window to determine values necessary for this exercise. 5. feel comfortable transferring data to the Journal and interpreting that data to answer questions about their recordings.
Included with:
Lab Equipment Required: Description: Students will observe and record spontaneous smooth muscle activity from the rat jejunum or ileum before recording and analyzing the responses of this tissue to physiologically relevant agents or conditions, such as: stretch, acetylcholine (ACH), curare with or without ACH, atropine with or without ACH, epinephrine, serotonin, changes in pH, changes in calcium ion concentration, and sodium cyanide.
Goals
1. Students will dissect a rat to be able to examine smooth muscle contractions. 2. Students will assemble the equipment needed to be able to record smooth muscle contractions. 3. Students will gather data corresponding to normal rhythmic smooth muscle contractions. 4. Students will test different parameters with regard to uterine muscle function: ◦ acetylcholine. ◦ atropine. ◦ epinephrine. ◦ serotonin, ◦ stretch and tension. 5. Students will continue to be successful at using the LabScribe software to move cursors, analyze data, record data to the Journal, and add functions to the Analysis window.
Outcomes
Students who have successfully completed this exercise will: 1. be able to record the spontaneous contractions of the intestine. 2. describe any qualitative differences in the contractions produced by Acetylcholine, Epinephrine and other pharmaceuticals. 3. understand the difference between excitation and inhibition 4. have used the functions available in the Analysis window to determine values necessary for this exercise. 5. feel comfortable transferring data to the Journal and interpreting that data to answer questions about their recordings.
Included with:
Lab Equipment Required: Description: In this laboratory exercise, students will record the effects of temperature on the amplitude and frequency of electrical activity in the frog heart, as well as the effects of the synaptic transmitters, epinephrine and acetylcholine on these same parameters.
Goals
1. Students will dissect a frog to expose the heart. 2. Students will assemble the equipment needed to be able to stimulate the heart and will record cardiac contractions to look at an ECG. 3. Students will understand the correlation between external stimuli and heart muscle response. 4. Students will gather data corresponding to normal heart rhythms. 5. Students will test different parameters with regard to cardiac muscle function and ECG recordings: ◦ cold temperature. ◦ warm temperature. ◦ epinephrine. ◦ acetylcholine. 6. Students will continue to be successful at using the LabScribe software to move cursors, analyze data, record data to the Journal, and add functions to the Analysis window.
Outcomes
Students who have successfully completed this exercise will: 1. be able to successfully isolate the frog heart. 2. gain an understanding of normal cardiac muscle contraction and normal amphibian ECG waves. 3. record cardiac muscle ECG waves to test a variety of hypotheses and reach scientific conclusions. 4. have used the functions available in the Analysis window to determine values necessary for this exercise. 5. feel comfortable transferring data to the Journal and interpreting that data to answer questions about their recordings.
Included with:
Lab Equipment Required: Description: In this laboratory exercise, students will use a force transducer to monitor the contractility of the crayfish heart as it is subjected to various imposed conditions, such as: the effect of adding Serotonin and GABA to change the heart rate and contractile force of the exposed heart; and the effect of cold temperature on cardiac muscle activity.
Goals
1. Students will dissect a crayfish to expose the heart. 2. Students will assemble the equipment needed to record cardiac contractions. 3. Students will understand the correlation between eternal stimuli and heart muscle response. 4. Students will gather data corresponding to normal heart rhythms. 5. Students will test different parameters with regard to cardiac muscle function: ◦ cold temperature. ◦ serotonin. ◦ GABA. 6. Students will continue to be successful at using the LabScribe software to move cursors, analyze data, record data to the Journal, and add functions to the Analysis window.
Outcomes
Students who have successfully completed this exercise will: 1. be able to successfully isolate the crayfish heart. 2. gain an understanding of normal cardiac muscle contraction. 3. record cardiac muscle contractions to test a variety of hypotheses and reach scientific conclusions. 4. have used the functions available in the Analysis window to determine values necessary for this exercise. 5. feel comfortable transferring data to the Journal and interpreting that data to answer questions about their recordings.
Included with:
Lab Equipment Required: Description: In this experiment, students will record the phasic and tonic responses of a byssal muscle to individual and repeated stimulus pulses, and the effects of the direct application of acetylcholine and serotonin to the muscles. Students will use the anterior byssal retractor muscle (ABRM), which has a dual origin at the anterior point of the valves and an insertion at the base of the foot. The ABRM is an example of a catch muscle, which is able to maintain a steady contraction with very little energy expenditure. This is an important ability to have in anaerobic environments. The ABRM tends to contract tonically by slowly generating force and maintaining the contraction for some time after the excitatory input has ceased. The ABRM is used because it is easily isolated, stimulated, and monitored by using a force transducer.
Goals
1. Students will dissect a marine mussel (Mytilus sp.) to expose the byssal retractor muscle. 2. Students will assemble the equipment needed to be able to stimulate the retractor muscle and will record muscle contractions to look at muscle twitch and responses to stimuli. 3. Students will be able to successively increase stimulation to cause changes in response of the muscle. 4. Students will deliver differing doses of neurotransmitters to see the effects on an actively contracting muscle: ◦ acetylcholine. ◦ serotonin. 5. Students will continue to be successful at using the LabScribe software to move cursors, analyze data, record data to the Journal, and add functions to the Analysis window.
Outcomes
Students who have successfully completed this exercise will: 1. be able to determine the relationship between the strength of the stimulus and the response of the muscle. 2. be able to measure the amplitude of contraction produced in a muscle that is stimulated with a long current pulse, and repeated pulses delivered at progressively higher frequencies. 3. understand the relationship between summation and tetanus. 4. observe the effects of acetylcholine and serotonin, the neurotransmitters that effect contraction and relaxation of the anterior byssal retractor muscle. 5. have used the functions available in the Analysis window to determine values necessary for this exercise and feel comfortable transferring data to the Journal and interpreting that data to answer questions about their recordings.
Included with:
Lab Equipment Required: Description: In this experiment, you will use a force transducer to record the effects of several transmitters on the rate and force of crayfish intestinal contractions. The recordings also reflect how smooth the peristaltic contractions are and indicate the degree of coordination between the longitudinal and circular muscle layers.
Goals
1. Students will dissect a crayfish abdomen to expose the gut and intestines. 2. Students will assemble the equipment needed to be able to dose the intestine with different drugs and will record muscle contractions to observe responses both type and concentration of drug. 3. Students will deliver differing doses of excitatory and inhibitory neurotransmitters to see the effects on an actively contracting muscle: ◦ acetylcholine. ◦ epinephrine. ◦ GABA. 4. Measure and understand contraction amplitudes and durations. 5. Students will continue to be successful at using the LabScribe software to move cursors, analyze data, record data to the Journal, and add functions to the Analysis window.
Outcomes
Students who have successfully completed this exercise will: 1. be able to record the spontaneous contractions of the intestine. 2. describe any qualitative differences in the contractions produced by Acetylcholine, Epinephrine and GABA. 3. understand the difference between excitation and inhibition 4. have used the functions available in the Analysis window to determine values necessary for this exercise. 5. feel comfortable transferring data to the Journal and interpreting that data to answer questions about their recordings.
Included with:
Lab Equipment Required: Description: The most convenient way of examining the properties of the motor unit is by use of the nerve-muscle preparation. With an exposed, centrally ligated nerve trunk (e.g. frog sciatic) supplying a muscle group, a stimulator can be used to excite the distal end of the exposed nerve. Activation of part or all of this trunk will cause a contraction in the innervated muscle. However, even when a successfully propagated impulse has been initiated in a nerve fiber, it must be conducted across the neuromuscular junction to be effective in causing a contraction of the muscle. Not only is a finite time occupied in the transmission of the nerve impulse across the junction, but the junction itself is very sensitive to fatigue and to its chemical environment.
Goals
1. Students will dissect a frog leg to extract the sciatic nerve and the muscles of the lower limb (either the gastrocnemius or tibialis anterior). 2. Students will assemble the equipment needed to be able to stimulate the nerve and muscles, and record compound action potentials from both. 3. Students will understand the correlation between nerve stimulus and muscle responses. 4. Students will test synaptic delay between nerve and muscle compound action potentials. 5. Students will test stimulus frequency, fatigue, and myoneural blocking. 6. Students will continue to be successful at using the LabScribe software to move cursors, analyze data, record data to the Journal, and add functions to the Analysis window.
Outcomes
Students who have successfully completed this exercise will: 1. be able to successfully excise the sciatic nerve and muscles of a frog’s leg. 2. have a better understanding of electrical stimulation of nerve fibers and the equipment used to perform such stimulation. 3. gain an understanding of both nerve and muscle compound action potentials and how they relate to each other. 4. record compound action potentials from the sciatic nerve and lower limb muscles to test a variety of hypotheses and reach scientific conclusions. 5. have used the functions available in the Analysis window to determine values necessary for this exercise. 6. feel comfortable transferring data to the Journal and interpreting that data to answer questions about their recordings.
Included with:
Lab Equipment Required: Description: In this experiment the student will remove the combined crop-gizzard from the animal and place it in a tissue bath at room temperature. Once the tissues are connected to a force transducer, the student can record spontaneous contractions and the effects of neurotransmitters like acetylcholine and serotonin.
This experiment has none of the disadvantages of the mammalian exercise. The animals can be purchased from a bait shop for only a few dollars a dozen, kept in the refrigerator until needed, and used at room temperature. Furthermore, since they are invertebrates, no special authorization is required.
Goals
1. Students will dissect an earthworm to be able to examine smooth muscle contractions. 2. Students will assemble the equipment needed to be able to record smooth muscle contractions. 3. Students will gather data corresponding to normal rhythmic smooth muscle contractions. 4. Students will test different parameters with regard to smooth muscle function: ◦ acetylcholine. ◦ serotonin ◦ epinephrine. 5. Students will continue to be successful at using the LabScribe software to move cursors, analyze data, record data to the Journal, and add functions to the Analysis window.
Outcomes
Students who have successfully completed this exercise will: 1. be able to successfully isolate earthworm gut 2. activate and record uterine muscle contractions to test a variety of hypotheses and reach scientific conclusions. 3. gain an understanding of rhythmic smooth muscle contractions. 4. have used the functions available in the Analysis window to determine values necessary for this exercise. 5. feel comfortable transferring data to the Journal and interpreting that data to answer questions about their recordings.
Included with:
Lab Equipment Required: Description: As the heart contracts, its electrical activity can be recorded and displayed in an electrocardiogram (ECG). While the crustacean ECG does not have the characteristic components of the vertebrate ECG, a coordinated depolarization is clearly identifiable, and is analogous to the QRS complex of the vertebrate ECG. This is followed by a slower wave corresponding to the heart’s repolarization, a wave that is analogous to the T wave of the vertebrate ECG.
The mechanical activity of the crayfish heart can be monitored by a force transducer, and that exercise is available as Experiment AM-5. In this laboratory exercise, students will record the electrical activity of the heart, looking at the effects of temperature on heart rate and on the amplitude of the components of the ECG, which represent the heart’s summed electrical activity. The effects of two modulatory chemicals, serotonin and GABA, are also explored.
Goals
1. Students will dissect a crayfish to expose the heart. 2. Students will assemble the equipment needed to be able to stimulate the heart and will record cardiac contractions to look at an ECG. 3. Students will understand the correlation between external stimuli and heart muscle response. 4. Students will gather data corresponding to normal heart rhythms. 5. Students will test different parameters with regard to cardiac muscle function and ECG recordings: ◦ cold temperature. ◦ warm temperature. ◦ epinephrine. ◦ acetylcholine. 6. Students will continue to be successful at using the LabScribe software to move cursors, analyze data, record data to the Journal, and add functions to the Analysis window.
Outcomes
Students who have successfully completed this exercise will: 1. be able to successfully isolate the frog heart. 2. gain an understanding of normal cardiac muscle contraction and normal crayfish ECG waves. 3. record cardiac muscle ECG waves to test a variety of hypotheses and reach scientific conclusions. 4. have used the functions available in the Analysis window to determine values necessary for this exercise. 5. feel comfortable transferring data to the Journal and interpreting that data to answer questions about their recordings.
