VPB 121: Veterinary Physiology - II (2+1)

COMPONENTS OF PHYSIOGRAPH

• Physiograph comprises of the following 

Main Console

It has three basic components.

• Chart drive
  • It is a multispeed chart drive and provides paper speeds ranging from 0.25 to 100 mm / second. The speed can be adjusted using a selector knob and push button.
• Pen recording system
  • Two recording pens - one for the muscle event recording and the second one for the time / event marker. The contact tension of the pens can be adjusted with the help of cradle springs. A pen lift knob lifts the pens from the paper.
• Main amplifier
  • It is common to all couplers. A 50Hz toggle switch cuts off unwanted interference. A base control knob is available to adjust the position of the pen. Another control is used to select sensitivity of the amplifier ranging from 50 to 500 mV in 4 steps and from 1 to 100 mV in 7 steps.
  • Three screwdriver adjustments are provided on the sides of the main console. Once adjusted they do not require to be adjusted. The side of the console also has IN and OUT jackets. The OUT jacket of one physiograph can be connected to IN jacket of another unit and both units will record simultaneously from the same experimental set up. Another IN jacket is used to connect electronic stimulator to record Event / Time events.
• Coupler housing
  • Various interchangeable couplers can be just plugged into the coupler housing.

Couplers

• Bio-potential coupler
  • It is useful to record any AC phenomenon like ECG, EEG, EMG, and ERG recording, nerve conduction velocities, movements of the eye etc. A coupler knob selector selects the phenomenon to be recorded. It has a CAL position to check calibration, for which a push but­ton is provided.
• EKG Coupler
  • Used for recording of clinical ECG (EKG). There is a knob for selecting various leads and another knob for calibration.
• Strain gauge couplers and isotonic fine movement
  • These couplers record activity from various strain gauge transducers - pressure volume, muscle force transducers etc. They are useful to record muscle and heart activity, for all experiments on frog sciatic-nerve gastrocnemious preparation like simple twitch, successive stimiuli, tetanus, fatigue, isometric and isotonic contractions, effect of load, muscle stretch reflexes, experiments on frog heart in-vivo, B.P. of cannulated animals.
• Pulse - Respiration Coupler
  • Useful to record arterial pulse with a photoelectric pulse transducer and respiration with respiration transducer. A toggle swtich selects pulse or respiration mode.
• Temperature Coupler
  • Useful to record rectal or surface temperature. The transducer has to be calibrated within a temperature range using water bath.

Transducers

• Used to transform the mechanical activity into electrical activity.

Electronic Stimulator

• Can be used in two modes.
  • As time/event marker.
  • To provide electrical stimuli up to 30 V as asingle pulse, as 2 successive stimuli with time intervals ranging from 0.5 to 100 / sec.

Electrodes

• ECG electrodes, EEG electrodes and EMG electrodes.

Components of Physiograph
Main Console	Couplers	Transducers	Electronic Stimulator	Electrodes
Chart drive	Bio-potential coupler
Pen recording system	EKG Coupler
Main amplifier	Strain gauge couplers and isotonic fine movement
Coupler housing	Pulse- Respiration Coupler
	Temperature Coupler