This set of Biomedical Instrumentation online test focuses on “Multi-Channel Wireless Telemetry System”.
1. _________ instrument is used for recording the electrical activity of the muscles.
Explanation: Electromyograph is an instrument used for recording the electrical activity of the muscles to determine whether the muscle is contracting or not; or for displaying on the CRO and loudspeaker the action potentials spontaneously present in a muscle or those induced by voluntary contractions as a means of detecting the nature and location of motor unit lesions; or for recording the electrical activity evoked in a muscle by the stimulation of its nerve.
2. EMG cannot be recorded by using surface electrodes.
Explanation: It is False. EMG is usually recorded by using surface electrodes because the surface electrodes may be disposable, adhesive types or the ones which can be used repeatedly.
3. Which of the following signal is used to myoelectric prosthetic devices?
Explanation: EMG measurements are also important for the myoelectric control of prosthetic devices (artificial limbs). This is the most demanding requirement from an EMG since on it depends on the working of the prosthetic device. This use involves picking up EMG signals from the muscles at the terminated nerve endings of the remaining limb and using the signals to activate a mechanical arm.
4. _________ is the most common and convenient source of light.
a) Neon-xenon arc
b) Xenon-mercury arc
c) Tungsten lamp
d) Hydrogen discharge lamp
Explanation: The most common and convenient source of light is the tungsten lamp. This lamp consists of a tungsten filament enclosed in a glass envelope. It is cheap, intense and reliable. A major portion of the energy emitted by a tungsten lamp is in the visible region and only about 15 to 20% is in the infrared region.
5. Which of the following factor determines the amplitude of EMG signal?
b) Ventricular Volume
c) Blood Resistivity
d) Position of electrode
Explanation: The amplitude of the EMG signals depends upon various factors, e.g. the type and placement of electrodes used and the degree of muscular exertions. The needle electrode in contact with a single muscle fibre will pick up spike type voltages whereas a surface electrode picks up many overlapping spikes and therefore produces an average voltage effect.
6. EMG signals range from ______________
a) 0.1 to 0.5 mV
b) 0.050 to 0.1 mV
c) 0.5 to 1 mV
d) 0.025 to 0.050 mV
Explanation: A typical EMG signal ranges from 0.1 to 0.5 mV. They may contain frequency components extending up to 10 kHz.Such high frequency signals cannot be recorded on the conventional pen recorders and therefore, they are usually displayed on the CRT screen.
7. Modern day calorimeters and spectrophotmetry instruments use ________ light source.
a) Tungsten-halogen lamp
b) Xenon-mercury lamp
c) Deuterium discharge lamp
d) Mercury arc
Explanation: Modern instruments use a tungsten-halogen light source, which has a higher intensity output than the normal tungsten lamp in the change over a region of 320–380 nm used in colorimetry and spectrophotometry. It also has a larger life and does not suffer from blackening of the bulb glass envelope.
8. Which of the following from the options is included in the system to facilitate playback and study of EMG sound waveforms at a later convenient time?
a) Tape Recorder
d) Ground Electrode
Explanation: The waveform can also be photographed from the CRT screen by using a synchronized camera. The tape recorder is included in the system to facilitate playback and study of the EMG sound waveforms at a later convenient time.
9. ____________ is necessary for providing a common reference for measurement?
a) active electrode
b) ground electrode
c) tape recorder
Explanation: A ground electrode is necessary for providing a common reference for measurement. The signal can then be amplified and displayed on the screen of a cathode ray tube. It is also applied to an audio amplifier connected to a loudspeaker. These electrodes pick up the potentials produced by the contracting muscle fibres.
10. Which among the following are optical systems, which provide better isolation of spectral energy than the pptical filters.
Explanation: Monochromators are optical systems, which provide better isolation of spectral energy than the optical filters, and are therefore preferred where it is required to isolate narrow bands of radiant energy. Monochromators usually incorporate a small glass of quartz prism or a diffraction grating system as the dispersing media.
11. _______________ is not an arrhythmic condition.
a) Cardiographic beat
c) Ectopic beat
d) Dropped beat
Explanation: These are bradycardia, tachycardia, dropped beat and premature beat. The analyzer part in automatic scanning of ambulatory records looks for four arrhythmic conditions. A threshold control is associated with each of these and when the appropriate threshold is exceeded, an alarm condition is generated.
12. CMRR of preamplifier upto 5 Khz should be _____________
a) 10 dB
b) greater than 90 dB
c) less than 90 dB
d) 30 dB
Explanation: The common-mode rejection should be greater than 90 dB up to 5 kHz. The main amplifier has controls for gain adjustment from 5 mV/div to 10 mV/div for selecting the sensitivity most appropriate to the incoming signal from the patient. A calibrating square wave signal of 100 mV (peak-to-peak) at a frequency of 100 Hz is usually available.
13. Holter Cardiography is ambulatory monitoring of ECG signal.
Explanation: Modern EMG machines are PC based available both in a console as well as laptop models as they provide full colour waveform display, automatic cursors for marking and making measurements and a keyboard for access to convenient and important test controls. Ambulatory monitoring of ECG is called ‘Holter Cardiography’, after Dr. Norman Holter who introduced this concept in 1962. A Holter monitor is a type of ambulatory electrocardiography device, a portable device for cardiac monitoring (the monitoring of the electrical activity of the cardiovascular system) for at least 24 hours (often for two weeks at a time).
14. _____________ provides an excellent review of ambulatory cardiac event recorders.
Explanation: An excellent review of ambulatory cardiac event recorders is provided by Benz in 1999. The major advantage of these devices compared with a traditional Holter monitor is that they are small, allow ECG monitoring for longer time periods, and can provide nearly real time data analysis when the patient transmits a recording in proximity to the symptomatic event.
15. ________ CPU has overall system control responsibility.
c) Control and timing
d) Acquisition and display
Explanation: It also handles individuals functions such as keyboard and direct writer interface, tape deck control, timing data processing, and arrhythmia count totalizing via a high speed interrupt system. The control and timing CPU has an overall system control responsibility.
Sanfoundry Global Education & Learning Series – Biomedical Instrumentation.
To practice all areas of Biomedical Instrumentation for online tests, here is complete set of 1000+ Multiple Choice Questions and Answers.