Ministry of education and science of ukraine sumy State University medical institute department of Physiology and Pathophysiology
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PRACTICAL CLASS #3 Date: ____________ ^ Questions for discussion:
Literature: Guyton, Arthur C. Textbook of medical physiology – Ch. 5,7. Practical work #1 “A study of the bioelectric phenomena in living tissues. The 1st Galvani’s experiment.” In excitable tissues, the bioelectric phenomena can be observed by both biological and physical methods. Although the biological method in our time lost the value as a research method, for a physiologist it will always be interesting due to a prominent role which it played in history of opening of the bioelectric phenomena. At the biological method by Galvani was the first to lead to the existence of «animal electricity» and the same time begin a new direction in physiology – studies about electric processes in an organism. Essence of the first experience of Galvani shows that when touched with bimetallic pincers a preparation of gastrocnemius muscle, there is reduction of muscles. The current which arises between two heterogeneous metals, copper and iron, is the reason of irritation of the muscle. Materials and equipments: set of preparing tools (anatomic pincers, small scissors, large scissors, scalpel, probe), physiological solution, preparing small planks, serviettes, cotton wool, tray, electrostimulator, with electrodes, bimetal pincers with copper and zinc ends, a research object is a frog. Procedure:
 Fig.1 Results: 1 What’s observed when you touch the nerve-muscular preparation with metallic pincers? 2 To draw the scheme of the experiment. 1_________________________________________________________________________________________________________________________________________________________ 2 The scheme of experiment: Conclusion: 1 How was the proved existence of the bioelectric phenomena proved in excitable structures? 2 What is the reason of irritation of a muscle? _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ^ nd Galvani’s experiment This experiment of Galvani consisted of the reduction of muscles of frogs foot was reproduced without participation of a metal, by throwing of preparation of sciatic nerve on the damaged area of thigh. Difference of potentials between an external surface of a muscle and the inside surface, which exists at rest, expressly shows up when a muscle is damaged. Potential which arises up between unharmed and damaged areas is called «potential of damage». When a nerve gets on the damaged electronegative area of muscle, there is shorting of chain, in which positive pole (the unharmed surface of muscle) and the area of nerve which compresses with it take part. Thus in the second experiment of Galvani reason of excitation of nerve is an irritating action of current which arises directly in tissues. Between an external surface of a muscle and the inside surface in a state of rest, is a difference potential, which brightly shows up at a damage. Potential which arises between the damaged and unharmed areas of a muscle, «potential of damage» can be reason of excitation a nerve. Procedure:
   Fig. 2 Fig. 3 Fig. 4 Results: 1 What was observed after the contact of the sciatic nerve of rheoscopic paw with the damaged area of muscle of the second half of frog? 2 To draw the scheme of experiment. 1______________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 2 The scheme of experiment: Conclusion: What arises up between the damaged and unharmed areas of a muscle, how does it influence on a rheoscopic paw experiment? _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ^ Matteuchi showed that it is possible to cause reduction of muscles of nerve-muscular preparation, by putting a nerve to the muscles of the second preparation, which grow short. This experiment demonstrates that in a muscle which grows short there are considerable currents, which can be utilized in the quality of an irritant for the nerve of the second preparation. These currents are called «currents of action». Procedure:
 Fig. 5 Results: 1) How does excitation of muscle of the first preparation affect the state of the second preparation? 2) Draw the location of rheoscopic quotation marks in experience of Matteuchi. 1______________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 2 The scheme of experiment: Conclusion: Why is there reduction of muscles of the second preparation at reduction of muscles of the first preparation? ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Teacher’s signature ___________________ Work for the independent exercise: 1. Draw graphically law of force-time. Mark needed points.  
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____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ PRACTICAL CLASS #4 Date:____________ ^ Questions for discussion: 1. Structural organization of the skeletal muscle. 2. The theory “sliding myofilaments” of the muscle contraction. 3. The structure of actin and myosin filaments. 4. The “walk-along” theory “of the muscle contraction. Fenn effect (ATP) 5. Stages of muscle contraction. 6. The concept of the motor unit. Classification of motor units. Fast fibers, slow fibers. 7. Physiological characteristics of muscle contraction: length of the sarcomer, isometric – isotonic, multiple fiber, summation – frequency summation (tetanization), muscle hypertrophy - muscle atrophy, muscle tone – muscle fatigue. 8. Types of the smooth muscle. Physical basis for smooth muscle contraction. Literature: Guyton, Arthur C. Textbook of medical physiology – Ch. 6,7. Practical work #1: The determination of the absolute muscular strength of a hand. Materials and equipments: dynamometers. Procedure:
A tester in the standing position takes his hand with a dynamometer aside on the right angle of 90° in relationship to the body. Another hand is let down and relaxed. On a signal the tester makes the maximum efforts on the dynamometer 5 times with an interval in 5 seconds. One should hold the dynamometer by fingers without jerks but with all his strength. Every result should be fixed down. The muscular strength is estimated on the best result. Results: f1=________ f2=________ f3=________ f4=________ f5=________ Conclusion: The absolute muscular strength of the hand is _______________ H/cm2 Practical work #2: The determination of the level of the ability to work of a hand. Materials and equipments: dynamometers. Procedure:
P = (f1 + f2 + f3 + f4 + f5 + f6 + f7 + f8 + f9 + f10):10 P- is the ability to work level, f – the dynamometer index. Results: f1 =______ f6 =_______ f2 =______ f7 =_______ f3 =______ f8 =_______ f4 =______ f9 =_______ f5 =______ f10 =_______ P = (_____+ _____+ ______+ ____ + _____ + _____ + _____+ _____ + ____ + ____) : 10 = P = _________ Conclusion: The levels of the muscular ability to work is ___________________ H/cm2 ^ Materials and equipments: dynamometers. Procedure: Using the results that had been received in the experiment 2, one should calculate the reduction of the ability to work index with the help of the formula: S = ((f1 - fmin) : fmax) x 100% S – is the reduction of the ability to work index; f1 - the rate of the primary dynamometry =_________________________ fmax - the maximum rate of efforts =______________________________ fmin - the minimum rate of efforts=________________________________ Results: 1. S = ((______ - ______) : ______ ) x 100% S = ____________% 2. Draw the graph that will make clear the character of ability to work reduction: On the abscissa axis you should put down the numbers of efforts, on the coordinate axis you should put down of the dynamometer on every effort. Score dynamometer  Number efforts1 2 3 4 5 6 7 8 9 10 Conclusion: the reduction of the ability to work index is ___________________ % Teacher’s signature ___________________ Work for the independent exercise:
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__________________________________________________________________________________________________________________________________________________________________________ 6. Calculate, which must irritate the minimum frequency of muscle to get: a) incomplete tetanus, b) complete tetanus. If irritation single length of the muscle contraction - 0.02 sec, relaxation time - 0.03 sec (latent period lasts 0.002 sec, it can be neglected). __________________________________________________________________________________________________________________________________________________________________________ PRACTICAL CLASS #5 Data:_______________ THEME: "^ ". Questions for discussion:
Literature: Guyton, Arthur C. Textbook of medical physiology – Ch. 2,4,5,6,7. PRACTICAL CLASS #6 Date:____________ |
