Southern Oregon Video Enterprises, Inc.

Contents of Frog Skeletal Muscle

	Background
	Determination of Threshold
	Twitch Amplitude and Duration
	Summation, Tetanus and Fatigue

Details of Frog Skeletal Muscle

This program deals with the characteristics of whole muscle contraction. The tape begins with a consideration of the terms tension and load. Following an introduction to these terms, differences between isotonic and isometric recordings are presented. The equipment used to study isometric contractions is demonstrated.

The dissection of the muscle-femur preparation is illustrated via a series of diagrams. The actual apparatus for recording muscle contractions is presented. This equipment includes a Tektronix model 5113 dual beam, dual trace storage oscilloscope, a Grass model S-44 stimulator and a model FT .03 transducer. Calibration of the transducer is demonstrated .

With the foregoing serving as background information, the tape introduces the muscle twitch. Following this introduction to twitch contraction, the tape considers the determination of threshold, twitch amplitude and duration. Next, the tape concludes with a series of demonstrations of treppe, incomplete tetanus, complete tetanus and ultimately fatigue. Two channels of information are available on this tape. At selected points in the presentation a data readout of both the stimulus and the response is provided.

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Contents of Frog Skeletal Muscle

bullet Background

bullet Determination of Threshold

bullet Twitch Amplitude and Duration

bullet Summation, Tetanus and Fatigue

Details of Frog Skeletal Muscle

This program deals with the characteristics of whole muscle contraction. The tape begins with a consideration of the terms tension and load. Following an introduction to these terms, differences between isotonic and isometric recordings are presented. The equipment used to study isometric contractions is demonstrated.

The dissection of the muscle-femur preparation is illustrated via a series of diagrams. The actual apparatus for recording muscle contractions is presented. This equipment includes a Tektronix model 5113 dual beam, dual trace storage oscilloscope, a Grass model S-44 stimulator and a model FT .03 transducer. Calibration of the transducer is demonstrated .

With the foregoing serving as background information, the tape introduces the muscle twitch. Following this introduction to twitch contraction, the tape considers the determination of threshold, twitch amplitude and duration. Next, the tape concludes with a series of demonstrations of treppe, incomplete tetanus, complete tetanus and ultimately fatigue. Two channels of information are available on this tape. At selected points in the presentation a data readout of both the stimulus and the response is provided.

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Contents of the Cardiac Cycle of the Turtle

	Background
	Effects of Temperature
	Nature of the Refractory Period
	Electrocardiogram
	Starling's Law of the Heart
	Effects of Vagal Stimulation

Details of the Cardiac Cycle of the Turtle

The second program deals with the events of the cardiac cycle and the intrinsic and extrinsic factors that control it. The tape begins by comparing the human heart to that of a turtle with respect to the origin of the pacemaking impulse and the rhythmic activity of pacemaker cells. Gross differences in the structure of the human and turtle heart are discussed.

The next segment of the tape demonstrates the turtle heart preparation itself and shows the external anatomy of the turtle heart. The tape demonstrates the attachment of transducers to record the atrial and ventricular myograms. The equipment utilized in the recording of the experimental variables is discussed and includes a Tektronix model 5113 dual beam, dual trace storage oscilloscope, two Harvard model 357 heart muscle transducers and a Grass model S-44 stimulator. The nature and time course of a myogram are discussed and the atrial and ventricular myograms are displayed on the storage scope.

The third segment of the tape examines the effects of temperature on heart rate followed by a demonstration of Starling's Law of the heart. The nature of the refractory period of cardiac muscle is explored by stimulation at different times during the cardiac cycle. The terms extra systole and compensatory pause are discussed and correlations are made with Starling's Law. Correlations between the physical and electrical events of the cardiac cycle are demonstrated next by simultaneous recordings of the atrial and ventricular myograms and of the electrocardiogram.

The tape illustrates the dissection of the vagus nerve preparatory to vagal nerve stimulation. The tape concludes by presenting the effects of vagal stimulation on heart rate. Inhibition followed by ventricular escape is shown. A data readout of the physiological information accompanies each of the sections and involves two or three channels of data.

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Contents of Nerve Impulse Part I

	Origen of Electrical Potentials
	Diphasic Action Potentials
	Dissection of the Frog Sciatic Nerve

Details of Nerve Impulse Part I

This video program deals with extracellular recording of the compound action potential in the frog sciatic nerve preparation. Part I of the tape provides background information for an understanding of the experimental information provided in Part ll.

Part one of this video program begins with a consideration of the general structure of a nerve cell. The tape then introduces the terms polarization, depolarization and repolarization and discusses the origin of the resting membrane potential and action potential. This is followed by a discussion of the recording of the diphasic compound action potential from the bullfrog sciatic nerve.

Part one concludes with a demonstration of the dissection and excision of the sciatic nerve from the bullfrog.

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