Read the passage and answer the following questions : Engineering measurement techniques have made substantial contributions in the accurate determinations of various physiological parameters, that give useful information to clinicians to detect the mal-functioning of the system being measured and also aid in proper diagnosis and patient care. Some of the biomedical instruments may be designed and developed for a particular specialised requirement but a majority of them are adaptations of widely used physical measuring devices. For monitoring the temperature of biomedical subjects, a thermister device is generally used along with a suitable bridge circuit in which the terminal device may be a voltmeter, calibrated in terms of degrees Celsius or Fahrenheit.
In the bio-electric phenomenon, ERG is used to detect
Retinal activity
Decode the abbreviation. ERG stands for electro-retino-gram — the record of the electrical response of the retina to a flash of light. All these names follow the same pattern: "electro" + the organ + "gram", so the middle syllable identifies the organ every time.
| Abbreviation | Organ | Records |
|---|---|---|
| ECG / EKG | cardio — heart | cardiac depolarisation |
| EEG | encephalo — brain | cortical activity |
| EMG | myo — muscle | motor unit potentials |
| ERG | retino — retina | photoreceptor response |
So options 1, 2 and 4 name the ECG, the EEG and the EMG respectively — each a real technique, but not this one.
How an ERG is taken. One electrode is placed in contact with the cornea (embedded in a contact lens or a fine fibre) and a reference on the skin near the eye. A calibrated light flash is delivered, and the retina's response appears as a characteristic waveform:
the a-wave, a negative deflection from the photoreceptors, followed by the b-wave, a larger positive deflection from the bipolar and Müller cells. The amplitude is of the order of a few hundred microvolts.
What it is used for. Because the a- and b-waves come from different retinal layers, the ERG can localise disease within the retina — it is used to diagnose retinitis pigmentosa and other inherited dystrophies, to assess retinal function when the media are too opaque for direct examination, and to monitor drug toxicity. Being an objective test, it works on patients who cannot cooperate with a subjective vision test, including infants.
Hence, ERG is used to detect retinal activity.
Similar Questions
Read the following statements regarding errors in measurement :
(a) Gross errors are mostly due to lack of knowledge and care on the part of the experimenter.
(b) Systematic errors are mostly caused by inherent short-comings of the instruments and components used in measurement.
(c) Random errors are due to sources and causes that cannot be specified for their effects with.
(d) Gross and systematic errors are non-correctable.
Which of the above are correct ?
Blood pressure is measured by
Assertion (A) : In a well-type manometer, ratio of cross-sectional areas of well and the tube is not the factor that determines the scale of the manometer.
Reason (R) : Accuracy of a manometer is not affected by the shape or size of the tubes.
Electrocardiogram is a graphical representation of electrical activity of heart muscle myocardium, in the form of
For the quantitative measurement of acidity or alkalinity, the instrument used is
The amplitude of an electrocardiograph signal is usually of the order of
An ammeter of 1 mA possesses a resistance of 100 ohms. This ammeter is to be converted into 1A ammeter. The value of shunt resistance required will be :
Followings is the sequence of blocks in spectrum Analyser :
A. Detector & video Amplifier
B. Fixed Frequency Active filter
C. Attenuator (Adjustable)
D. Mixer & Tunable Detector
Choose the correct answer from the options given below :
Read the following statements regarding biomedical instrumentations :
(a) Sphygmos is used for blood pressure measurement.
(b) EMG represents a record of the electrical activity of the brain.
(c) ERG represents the record of potential from the retina.
(d) ECG represents the record of electrical activity of brain.
Which of the above statements are correct ?
Optical pyrometers are used to measure :
Important Questions from Miscellaneous
The ration of the number of girls and boys in a school is 8 : 7. If the percentage increase in the number of girls and boys is 10% and 20% respectively, what will be the new ratio?
The cheapest means of transport is:
The property of Catenation is most readily predominant in:
Which newspaper edited by Bal Gangadhar Tilak, was one of the strongest critics of the British rule?
Which of the following is NOT a cause of food and water contamination?
