EI2311 BIOMEDICAL INSTRUMENTATION

Transcription

1 66 EI2311 BIOMEDICAL INSTRUMENTATION 1. What is meant by cell? UNIT I PHYSIOLOGY AND TRANSDUCERS The basic living unit of the body is cell. The function of organs and other structure of the body is understood by cell organization. 2. Write the abbreviation of RNA and DNA? 1. RNA Ribo Nucleic Acid 2. DNA De-Oxy Nucleic Acid 3. Write notes on resting potential, action potential and bio electric potential. The membrane potential caused by the different concentration of ions is called resting potential. It is caused by very rapid change of membrane permeability to sodium ions followed by recovery period. The positive potential of the cell membrane during excitation is called action potential. Certain systems of the body generate their own monitoring signals conveying useful information about the functions they represent. Such signals are bio electric potentials and are related to nerve conduction, brain activity, heart beat etc. 4. What is meant by resting potential? Equilibrium is reached with a potential difference across the membrane such that there is negative on the inside and positive on the outside. This membrane potential caused by the different concentration of ions is called resting potential. 5. What is meant by Action Potential? Cell has a slightly positive potential on the inside due to imbalance of potassium ions. This positive potential of the cell membrane during excitation is called action potential and is about 20 mv. 6. List out the factors to be considered when any medical Instrument is designed. Accuracy, frequency response, linearity, S/N ratio, stability and sensitivity 7. What is meant by electrode potential? The voltage developed at an electrode-electrolyte interface is known as electrode potential. 8. What is the purpose of electrode paste? The electrode paste decreases the impedence of the contact, then the artifacts resulting from the movement of the electrode or patient.

2 67 9. Write the different types of electrodes. The different types of electrodes are as follows: 1. Microelectrodes 2. Depth and needle electrodes 3. Surface electrodes 10. What are the different types of surface electrodes? The different types of surface electrodes are as follows: 1. Metal Plate electrodes 2. Suction cup electrodes 3. Adhesive tape electrodes 4. Multi point electrodes 5. Floating electrodes UNIT II ELECTRO PHYSIOLOGICAL MEASUREMENTS 1. What is meant by defibrillator? A defibrillator is an electronic device that creates a sustained myocardial depolarization of a patient s heart in order to stop ventricular fibrillation or artial fibrillation. 2. What are the characteristics of a DC amplifier? It may need balanced differential inputs giving a high common mode rejection ratio (CMRR). It should have extremely good thermal and long term stability. 3. What are the merits of a DC amplifier? The merits of a DC amplifier are 1. It is easy to calibrate at low frequencies. 2. It is able to recover from an overload condition unlike its AC counterpart. 4. Define Transducers Transducers are defined as a device which when actuated, transforms energy from one form to another. Generally, any physical parameters is converted into electrical form. 5. What are the types of transducers? The types of transducers are 1. Electrical transducer 2. Mechanical transducer 6. Write the parameters that dictate the transducer capability The parameters that dictate the transducer capability are 1. Linearity

3 68 2. Repeatability 3. Resolution 4. Reliability 7. Define Sensitivity Sensitivity is defined as the electrical output per unit change in the physical parameter. High sensitivity is generally desirable for a transducer. 8. What are the various types of electrical transducers? The various types of electrical transducers are 1. Active 2. Passive UNIT III NON-ELECTRICAL PARAMETER MEASUREMENTS 1. List out the parts of a transducer The parts of a transducer are 1. Sensing element 2. Transduction element 2. Write the factors considered while selecting a transducer. The factors that considered while selecting a transducer are 1. Operating range 2. Sensitivity 3. Frequency response & resonant frequency 4. Environmental compatibility 5. Minimum sensitivity Accuracy 6. Usage and ruggedness 7. Electrical parameters 3. What is meant by POT? POT is a resistive potentiometer used for the purpose of voltage division. It consists of a resistive element provided with a sliding contact called wiper. 4. Explain the working principle of a strain gauge. Strain gauge works on the principle that the resistance of a conductor or a semiconductor changes when strained. This property can be used for measurement of displacement, force and pressure. 5. List out the different types of strain gauges. The different types of strain gauges are 1. Un-bonded metal strain gauge

4 69 2. Bonded metal wire strain gauge 3. Bonded metal foil strain gauge 4. Vacuum deposited thin metal film strain gauge 5. Sputter deposited thin metal strain gauge 6. Bonded semiconductor strain gauge 7. Diffused metal strain gauge 6. What is meant by rosette? It is a combination of strain gauges to a single element strain gauge. 7. Write the working principles of variable inductance transducers. 1. Change of self inductance 2. Change of mutual inductance 3. Production of eddy currents 8. What is meant by LVDT? It is the linear variable differential transformer which is used to translate the linear motion into electrical signals. It consists of a single primary winding and 2 secondary winding. 9. List out the advantages of LVDT. The advantages of LVDT are 1. High range of displacement measurement 2. Friction & electrical isolation 3. Immunity from external effects 4. High I/p and high sensitivity 5. Ruggedness 6. Low hysterisis & low power consumption UNIT IV MEDICAL IMAGING AND PMS 1. What is meant by digitizer? It is a digital encoding transducer that enables a linear or rotary displacement to be directly converted into digital form without intermediate forms of analog to digital (A/D) conversion. 2. What are the classifications of pacemakers? The classifications of pacemakers are 1. Fixed rate pacemakers 2. Ventricular Synchronous pacemakers

5 70 3. Demand pacemakers 4. Atrial Synchronous pacemakers 3. What are the different methods of stimulation? The different methods of stimulation are 1. External stimulation 2. Internal stimulation 4. What are the types of electrodes? Devices that convert ionic potentials into electronic potentials are called electrodes. There are three types of electrodes. They are as follows: 1. Micro electrode 2. Depth and needle electrode 3. Surface and needle electrode 5. What is meant by neuron and nerve fibers? The basic Units of the nervous system is the neuron. A bundle of individual nerve fibers is called a nerve.a neuron is a single cell with a cell body, called soma, one or more inputs fibers called dendrites and a long transmitting fiber called axon. Both axons and dendrites are called nerve fibers. 6. What are parts of central nervous system? It consists of 1010 neurons. The brain consists of cerebrum, cerebellum and brainstem. Cerebrums consist of two hemispheres and they are divided into frontal lobe, occipital lobe and temporal lobe. Cerebellum consists of two hemispheres. They regulate the coordination of muscular movements. 7. Write the parts that contain peripheral nervous system. The nerve fibers outside the central nervous system are called peripheral nerves. It consists of motor and sensory nerves. 8. Define Circulatory System It is defined as a type of transport system. It helps in supplying the oxygen and digested food to different parts of our body and removing CO2 from the blood. The heart is the center of the circulatory system.

6 71 UNIT V ASSISTING AND THERAPEUTIC EQUIPMENTS 1. Define Heart and Lung Heart is defined as a pumping organ which eats regularly and continuously for years. It beats seventy times a minute at rest. Contraction is systole and relaxation is diastole. 2. Define Circulation and Respiration From the engineering point of view, the circulation is a high resistance circuit with a large pressure gradient between the arteries and veins. The exchange of any gases in any biological process is termed as respiration 3. What is meant by transducer? It is a device which detects or senses the bio signal and converts it in to an electrical signal for bio signal processing 4. Define Strain Gauge It is an electrical device which is used to measure stress or pressure in terms of strain using the principle of change of resistively due to mechanical stress 5. How are transducers classified? They can be classified into different types based on the energy conversion, application and so on. They are two types Active transducer: A transducer that gives its output without the use of an excitation voltage or modulation of a carrier signal is called an active transducer. Passive transducer: A transducer that gives its output using an excitation voltage or modulation of a carrier signal is called a passive transducer. Generally the active transducer converts a non- electrical energy into electrical energy and converts an electrical into non electrical energy.