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Department of Electronics and Instrumentation Engg.
Sixth Semester
EI1351 - Biomedical Instrumentation
1.Explain the Cell Structure
The basic living unit of the body is a cell.Each organ in our body is an aggerate of many
different cells held together by intercellular supporting structures.Each type of cell is meant for
performing one particular function.Each cell consists of a centrally located nucleus,also called
cell core,,surrounded by cytoplasam. The nucleus is separated from thecytoplasam is separated
from the sorroundind fluids by a cell membarane. The different substances that make up the
cell one collectively called protoplasam which is mainly composed of
water,electrolytes,proteins,carbohydrates and lipids.
2. What are the applications of piezo electric sensors?
1) In cardiology
2) In phono cardiography
3) In blood pressure measurement
4) In measuring physiological accelerations
2. What are the different thermal sensors?
1) Thermo couples
2) Thermistors
3) Radiation sensors
4) Fibre optic detectors
3. Give the different types of inductive sensors.
1) Self inductance type
2) Mutual inductance type
3) Differential transformer type (LVDT)
4. What are the advantages of LVDT?
1) Wide range of linearity
2) Change of phase by 180 Deg When the core passes through the center position
3) Full-scale displacement is 0.1- 250mm.
4) Sensitivity is 0.5- 2 mV.
5. What are the limitations of capacitive sensor?
1) Inadequate for measuring most physiological variables because of their low
frequency components.
6. What is the principle of piezo electric sensors?
The piezo electric materials generate an electric potential when mechanically strained.
Conversely, an electric potential can cause physical deformation of the materials
7..Define Resting Potential
Certain type of cells within the body such as nerve and muscle cell are encased
ina semi permeable membarane that permits same substances to pas through the membarane,
while others are kept out,sorrounding the cells of the bosy are the bosdy fluids which are
conductive solutions of charge ions.The principal ions are sodium(na+),
Pottasiuum(e+) and chloride(cl-) the membarane of the excitable cells readily permits entry of
potassium and chloride ions but blocks the entry of sodium ions .since the various ions seek
balance between inside the cell and outside.Equlibrium is reached with the potential difference
across the membarane -ive on the inside and +ive on the outside of the cell.This membarane
potential is caleed the resting of the cell.
7. .Define Action Potential
When a section of cell membaraneis excited by a flow of ionic current or
same form of externally applied voltage the membarane changes its permaliablity and begins to
allow to some of the sodium ions to enter.This movement of sodium ions into the cell results in
an ionic current flow that further reduces the barrier of membarane to sodium ion rush into the
cell to try to reach to balance with the ions outside.At the same time potassium ions which
were higer in the concentration inside the cell during the resting stage try to leave the cell, but
are unable to move as rapidly as sodium ions. As a result the cell has a slightly positive
potential on the due to imbalance of potassium ions.This +ive potential is called action
potential and this spproaxmately +20mv .A cell in the action potential stage is said to be
depolarized. The process of changing from resting stage to action potential stage is called
4. Explain Bioelectric Potential
Bioelectric potential are generated at a cellular level.that is each cell is a
minute voltage generator .because positive and negative ions tend to concentrate unequally
inside and outside the cell wall, a potential difference is established and the cell becomes a
tiny biological battery.In the normal resting state of the cell it interior is negative with respect
to the outside when the cells "fires"however,the outside of the cell becomes momentarily
negative with respect to the interior .A short time later, the cell regains the normal state in
which the inside I sagain negative with respect to outside.This "discharging" and "recharging"
of the cell known as deploarisation and repolarisation respectively.
5. Name the factors that are considered in the design of biomedical instrument system.
4.Frequency Rsponse
9.Signal to noise ratio.
6. Name the physcological systems of the body.
1. Bio chemical System
2. Cardio vascular System
3. Regualted System
4. Nervous System
7.State the principal of the sodium pump
Once the rush of sodium ions through the cell membarane has stopped that is a new
syage of equlibrium is reached, the ionic currents that lowered the barrier to sodium ions are no
longer present and the membarane comes back into its orginal selectively permeable condition,
where in the passage of sodium ions from the outside to inside of the cell is again blocked.This
take a long timw for thw resting potential to develop again .But by the activeprocess called
sodium pump,the sodium ions are quickly transported outside of the cell and the cell again
becomes polarized and assumes its restirict potential.This process is called repolarisation.
8.Name the differenttypes of electrodes:
1.Micro Electrode
A) Mettalic
B) Non -Metallic
2.Depth and needle Electrode
3.Surface Electrode
9.Draw the structure of the Nerve Cell
10.Draw the Wave form of the resting and action potential.
11)What are the requirements of physiological signal amplifier or biomedical pre amplifier?
a)The voltage gain should be more than 100 db.
b)It should have low frequency response.
c)There is no drift in the amplifier.
d)The output impedance of the amplifier should be very small.
12)What are the different modes of operation of differential amplifier?
a)single ended mode
b)differential mode
c)common mode
13)What is single ended mode?
When either v1 or v2 is equal to zero,the operation of the differential amplifier is known as
single ended mode of operation.
14)What is differential mode?
The two input signals are equal but have opposite polarity at every instant of time.
In this case,the input signals are called differential mode signals.
15)What is common mode signal?
The input voltages appearing at the input terminals 1 and 2 are identical both in amplitude
and phase at every instant of time and the circuit is said to be in common mode.
16)What is CMRR in a differential amplifier?
It is the ratio of the amplification of the differential voltage ti the amplification of the
common mode voltage.
CMRR in db=20 log10 CMRR.
17)What is noise figure?
It is defined as the ratio of the signal to noise ratio at the input to the signal to noise ratio at
the output.
18)What are the advantages of the pre amplifier or instrumentation amplifier?
a)high stability
b)higher fidelity
c)high CMRR
d)high input impedance with the required gain.
19)What is chopper amplifier?
The chopper amplifier is used convert the dc or low frequency signal into a high frequency
signal.Then this modulated high frequency signal is amplified by conventional ac
amplifier.Then this is demodulated and filtered to get low frequency or dc signal.
20)What are the types of chopper amplifier?
a)mechanical chopper amplifier.
b)non mechanical chopper amplifier.
21) Neuron:
Neurons (also known as neurones, nerve cells and nerve fibers) are electrically
excitable cells in the nervous system that function to process and transmit information.
Neurons are typically composed of a soma, or cell body, a dendritic tree and an axon. The
majority of vertebrate neurons receive input on the cell body and dendritic tree, and transmit
output via the axon. Neurons communicate via chemical and electrical synapses, in a process
known as synaptic transmission
What is Electrocardiography?
It deals with the study of the electrical activity of the heart muscles. The potentials
originated in the individual fibres of heart muscle are added to produce the ECG
1. What are the various parts of generalized instrumentation system?
2.Primary sensing element
3.Variable conversion element
4.Signal processing unit
5.Output display
6.Control & feedback element
2. Give the classifications of biomedical instruments.
i) According to the quantity that is sensed, pressure, flow or temperature sensing
ii) According to the principle of transduction used, resistive, inductive, capacitive,
ultrasonic or electrochemical devices.
iii) According to the measurement techniques, cardio vascular, pulmonary, nervous
& endocrine systems.
iv) According to the clinical medical specialities, pediatrics, obstetrics, cardiology
or radiology.
1. What are the different types of ECG lead configurations?
Bipolar limb leads
Augmented unipolar limb leads
Chest leads
Frank lead system
2. Define the Einthoven Triangle
The closed path RA to LA to LL and back to RA is called Einthoven triangle.
According to Einthoven, in a frontal plane of the body, the cardiac electric field
vector is a two dimensional one.
3. Draw the Standard ECG.
4. What are the important parts of ECG recorder?
Patient cable and defibrillator protection circuit.
Lead selector switch
Bio- amplifier
Auxilliary amplifier
Isolated power supply
Output unit
Power switch
5. Draw the ECG curve for Bundle block
6. What is Electroencephalography?
It deals with the recording and study of electrical activity of the brain. By means of
electrodes attached to the skull of a patient, brain waves can be picked up and
7. What is Electromyography?
It is the science of interpreting and recording the electrical activity of the muscles
action potentials. Meanwhile, the recording of the peripheral nerve's action
potential is called electroneurography.
8. Draw the block diagram of EMG recording setup.
9. What is Electrooculography?
It deals with the recording of the corneal- retinal potentials associated with eye
10. What is Electroretinography?
It deals with the recording and interpreting of the electrical activity of the eye. If the
illumination of the retina is changed, the potential changes slightly in a complex
manner. The recording of these changes is called Electroretinograph.
11. List the brain waves and their frequency.
Alpha- 8 to 13Hz, Beta-13 to 30 Hz , Theta- 4 to 8 Hz, Delta- 0.5 to 4 Hz.
12. Define latency.
It is defined as the elapsed time between the simulating impulse and the muscle's
action potential.
13. What are the different sounds made by the heart?
Valve closure sounds, Ventricular filling sounds, Valve opening sounds,
Extracardiac sounds
14. Name the parts of the heart conduction system.
Sino atrial node, Atrio ventricular node, Bundle of His , Purkinje fibres.
15. What is the colour coding of the different leads?
White -RA, Black- LA, Green- RL , Red- LL, Brown- Chest
16. Mention any four specifications of the ordinary ECG recorder.
Maximum sensitivity - 20 mm/mV, Input impedance -5 mega ohms, Output
impedance -<100 ohms, cmrr- 10000:1.
Unit III
1. What are the types of measurements of blood pressure?
A. 1. Indirect or noninvasive method.
2. Direct or invasive method.
2. How is the blood pressure measured in the indirect method?
A. the indirect method of measuring blood pressure involves the use of a
sphygmomanometer and a stethoscope. The sphygmomanometer consists of an
inflatable pressure cuff and a mercury or aneroid manometer to measure the
pressure in the cuff. The cuff is normally manually inflated, with a rubber bulb
and deflated slowly through a needle valve.
3. Explain the principle of sphygmomanometer.
A. The sphygmomanometer works on the principle that when the cuff is placed on
the upper arm and inflated, the arterial blood can flow past the cuff only when
the arterial pressure exceeds the pressure in the cuff. Further more, when the
cuff is inflated to a pressure that only occludes the brachial artery, turbulence is
generated in the blood as it spurts through the tiny arterial opening during each
systole. The sounds generated by this turbulence, Korotkoff sounds, can be
heard through the stethoscope placed over the artery downstream from the cuff.
4. What are the methods involved in direct blood pressure measurement?
A. 1. Auscultatory method
2. Palpatory method
Auscultatory method locate the systolic and diastolic pressure valves by
listening to the Korotkoff. Diastoslic pressure can be easily measured.
Palpatory method is a alternative method that the physician identifies the
flow of blood in the artery by feeling the pulse of the patient downstream from
the cuff instead of listening for the korotkoff sounds. In this method, systolic
pressure can be easily measured.
5. What is meant by mean arterial pressure(MAP)?
A. Mean Arterial pressure is the weighted average of the systolic and diastolic
pressure MAP falls about one- third of the way between the diastolic low and
systolic peak. Formula for calculating MAP is,
MAP = 1/3 (systolic -diastolic) + diastolic
6. What are the methods involved in direct blood pressure measurement?
A. 1. Percutaneous insertion
2. Catheterization(Vessel Cutdown)
3. Implantation of a transducer in a vessel or in the heart.
4. Other methods such as clamping a transducer on the intact artery have also
been used. But they are not common.
7. Explain the two ways involved in measurement of blood pressure with a catheter?
A. Measurement of blood pressure with a catheter can be achieved in two ways.
1. The first is to introduce a sterile saline solution into catheter so the fluid
pressure is transmitted to a transducer outside the body a complete fluid
pressure system is set up with provisions for checking against atmospheric
pressure and for establishing a reference point. The frequency response of
this system is a combination of the frequency response of the transducer and
the fluid column in the catheter.
2. In the second method, pressure measurements are obtained at the source.
Here, the transducer is introduced into the catheter and pushed to the point
at which the pressure is to be measured, or the transducer is mounted at the
tip of the catheter. This device is called a catheter-tip blood pressure
8. Discuss the technique involved in direct measurement?
A. 1)A catheterization method involving the sensing of the blood pressure through
a liquid column. In this method the transducer is external to the body and the
blood pressure is transmitted through a saline solution column in a catheter to
this transducer.
2) A catheterization method involving the placement of the tranducer through
the catheter at the actual size of measurement
In the bloodstream or by mounting the transducer on the tip of the catheter.
3)Percutaneous methods in which the blood pressure is sensed in the vessel just
under the skin by the use of a needle or catheter.
4)Implantation techniques in which the transducer is more permanently placed
in the blood vessels or the heart by surgical methods.
9)What are the different types of bloodflow meters?
1)Magnetic bloodflowmeter -Based on the principle of Magnetic induction.
2)Ultrasonic bloodflowmeter-Based on the principle if Doppler.
3)Thermal convection-The rate of cooling is proportional to the rate of the flow of the
medium.This principle is also used to measure the gasflow.
4)Determination by Radiographic method-By the injection of a contrast medium into a
bloodvessel,the circulation pattern can be made visible.Record of the X-ray image,obstruction
can be detected and the bloodflow in the bloodvessels can be estimated.This technique is
known as 'angiography'.
10)What is cardiac output?
The bloodflow at any point in the circulatory system is the volume of blood that passes
that point during a unit of time.It is measured normally in millimeter per min or litres per
min.Blood flow is highest in the pulmonary artery and the aorta,where the blood vessels leave
the heart.The flow at these points is called 'cardiac output'.
11)What is meant by pH?
pH can be defined as the logarithm of the reciprocal of the H+ ion concentration.It is a
measure of the acid-base balance of a fluid.
pH= - log10 [H+] = log10( 1/[H+])
12)What is the pH value for blood?
The pH value of normal arterial blood ranges between 7.38 and 7.42.The pH
of venous blood is 7.35,because of the extra CO2.
13)Define GSR.
GSR is used for measuring variations in perspiration.In response to an external
stimulus,such as touching a sharp point,the resistance of the skin shows a characteristic
decrease and this is known as Galvanic Skin Response.The GSR is believed to be caused
by the activity of the sweat glands.
14)Give the name of the instrument used for respiratory volume measurements and what are its
The most widely used instrument for respiratory volume measurements in the
recording spirometer.The different types of spirometer are
· Standard spirometer
· Waterless spirometer
· Wedge spirometer
· Electronic spirometer
· Broncho spirometer
15) Give the name of the instrument used for measuring airflow and explain its principle.
Pneumotachometer can be used for measuring airflow.This device utilizes the
principle that air flowing through an orifice produces a pressure difference across the
orifice that is a unction of the velocity of the air.
16) Define MVV.
Maximal voluntary ventilation is a measure of the maximum amount of air that
can be breathed in and blown out over a sustained interval, such as 15 or 20seconds.
17)What is FVC?
Forced Vital Capacity (FVC) is the total amount of air that can forcibly be
expired as quickly as possible after taking the deepest possible breath.
18)What is FRC?
The functional residual capacity(FRC) is the volume of gas remaining in the
lungs at the end expiratory level.It the sum of the residual volume and the expiratory
reserve volume.
19)Differentiate between tidal volume and residual volume.
The tidal volume (TV) or normal depth of breathing, is the volume of gas
inspired or expired during each normal, quiet, respiration cycle.
The residual volume (RV), is the volume of gas remaining in the lungs at the
end of a maximal expiration.
20)Define total lung capacity.
Total Lung Capacity is the amount of gas contained in the lungs at the end of a
maximal inspiration .It is also the sum of residual volume and vital capacity.
Unit - IV
1.Which are the elements of bio-telemetry system?
The essential elements are biological signal, transducer, conditioner, transmission link.
2.What are the types of radio telemetry systems?
Single channel telemetry system
Radio telemetry with a sub-carrier
Multiple channel telemetry system
3.What are the types of multiple channel telemetry systems?
Frequency system multiplex
Time division multiplex
4.What are the measurements in single channel telemetry system?
Active measurements
Passive measurements
7.What are the types of transducer used in ultrasonography?
Convex array
8. .What are the types of display modes used in ultrasonography?
9. .What are the recording devices used in ultrasonography?
Strip chart recorder
Video printer
Video recording
Polaroid camera
10. .What are the artifacts in ultrasonography?
Related to instrument problems
Improper operator technique
Due to interaction of sound.
11. Give the characteristics of X- Ray radiation .
When the fast moving electrons enters into the orbit of the anode material atom,its
velocity is contionously decreased due to the scattering of the orbiting electrons.Thus
the loss of energy of that incident electron appears in the form of continuous X-Rays or
white X-Rays which are called Bremsstrahlung Radiation.
12. Define Efficiency.
Effiency is defined as the ratio of X-Ray beam energy to the electron beam energy
which is normally 1.4*10-9ZVA. Where Z is the atomoc number of anode material ,VA
anode voltage normally in diagnosting radiology ,tungsten is used as the anode material
which has high melting point of about 33700C its atomic numbet Z=74
The minimum wavelength emitted by the X-Ray is given by
= hc/eva
= 12408/VA Ao
13. What is meant by soft and hard X-Ray ?
The anode voltage increases the l min decreases and henace X-Rays are called as hard
X-Ray .These are mainly used for therapeautic purpose .If the anode voltage VA
decreases then lmin increases and these are called softX-Ray .
14.Listthe basic components of X-Ray Machine
1.Power supply arrangement
5.Lead shield
15.Define contrast.
It is a measure of darkness of a desired image compare to its surroundings.The
contrast between two tissues is given by
C 12=10log I1/I2 Db
16.State the use of Bucky Diaphragm.
It is introduced between the patient and the film to improve the sharpness of the
image .It consists of thin lead veins separated by spaces of a low attenuation material.
The lead veins are usually angled so that the primary radiation which carries the
information can pass between them while these scattered radiation from the object are
17.Why aluminum filter is used in X-Ray tube.
The emitted rays of unwanted frequencies increase the patient those and the
decrease the image contrast. Aliminuim filters observes the lowest X-Ray frequency
and hence the intensity of low X-Ray frequencies incident on the patient is ready in use
Hence the negative effects produce by low frequency X-Rays are reduced.
18.Expalin the function of collimator
Between the patient and the X-Ray tube the collimator is placed .I t is an aperture
diaphragm which restricts the beam falling on the patient. the necessary shaping of the
X-Ray beam is done by it
19.State the classification of Artifact
It can be classified into 4 types
1.Noise Artifact
2.Motion Artifact
3.Artifact due to high differential absorption in the adjacent tissue
4.Technical errors and computer Artifacts.
20.Define NMR
In the presence of large magnetic field the spinning of nucleus in the atom and its axis
of rotation willprecess about the magnetic field. Each spin state has different energy. At
equilibrium, the lower state has more nuclei than the higher state. Using RF radiation
with an energy exactly equal to the energy difference between two nuclear energy
states. One state can achieve population inversion by raising the nuclei from the lower
energy states to the higher energy state .The excited nuclear spins will slowly return to
its equilibrium. Emitting the RF called Nuclear Magnetic Resonance
Unit V
1. What is a pacemaker?
Pacemaker is an electrical pulse generator that starts or maintains the normal
heart rhythm (i.e) application of electrical pulses to the heart is pacing action.
2. Explain the classification of pacemaker?
Pacemaker is broadly classified into internal & external pacemaker.
Total AV block requires internal pacemaker. It has a mini energy of 10µJ-100µJ
(5V,10mA,2ms).At a level of 400µJ, it causes Ventricular Fibrillation. Cardiac
Standstill is obtained by external pacemaker.
3. What are the types of pacemaker?
i. Ventricular synchronous(fixed rate pulse)
ii. Ventricular asynchronous(stand by pacemaker)
iii. Ventricular inhibited(demand pacemaker)
iv. Atrial synchronous pacemaker.
v. Atrial sequential ventricular inhibited pacemaker.
4. Explain the application of ventricular asynchronous or stand by pacemaker?
Ventricular asynchronous orstand by pacemaker is basically a simple
astable multivibrator that produces a stimulus at a fixed rate irrespective of the heart
5. What are the application of ventricular inhibited pacemaker?
i. The R wave inhibited pacemaker allows the heart to pace at its normal rhythm
when it is able to. If the R wave is missing for a preset period of time, the pacer
will supply a stimulus.
ii. When the sensor ( shielded inside the pacemaker) is slightly stressed or bent by
the patient's body activity, the pacemaker can automatically increase or decrease
its rate.Thus it can match with the greater physical effort.
6. What is the application of atrial synchronous pacemaker?
i. This type of pacing is used for young patients with a mostly stable block.
ii. It is used in stress testing & coronary artery diseases, in the evaluation of
severity of mitral stenosis & in the evaluation of various conduction
iii. It has been used to terminate atrial flutter & paroxymal atrial tachycardia.
iv. It can act as a temporary pacemaker for the atrial fibrillation.
7. What is an atrial sequential ventricular inhibited pacemaker and mention its
Atrial sequential ventricular inhibited pacemaker has the capability of
stimulating both the atria & ventricles and adopt its method of stimulation to the patient's
need .If atrial function fails, this pacemaker will stimulate the atrium & then sense the
subsequent ventricular beat.
8. What is a defibrillator?
A defibrillator is an electronic device that creates a sustained
myocardial polarisation of a patient's heart inorder to stop ventricular fibrillation or atrial
9 Explain ventricular fibrillation and how can it be eliminated?
Ventricular fibrillation is a serious cardiac energy resulting from
asynchronous contraction of the heart muscle.This uncoordinated movement of ventricle
walls of the heart may result from coronary occlusion, electric shock or abnormalities of
body chemistry.
10. What are the different types of defibrillators?
i. Internal Defibrillator
ii. External Defibrillator
a. AC. Defibrillator
b. DC. Defibrillator
c. Synchronous DC. Defibrillator
d. Square Pulse Defibrillator
e. Double Square Pulse Defibrillator
f. Biphasic DC Defibrillator
11.What are the different types of oxygenator?
Bubble oxygenator
Film oxygenator
Membrane oxygenator
Liquid-Liquid oxygenator
12.Define Heart-Lung Machine?
Heart Lung machine replaces the functions of heart and lungs thereby providing the rest
of the body with a continuous supply of oxygenated blood while the heart is stopped.
13.What are the requirements of ideal oxygenator?
Lower priming volume
Minimum trauma to blood
Simple, safe and reliable operation
Ensured sterilization
No microembolus formation and
Short preparation time
14.What is the principle of Liquid-Liquid oxygenator?
The oxygen dissolved fluorides organic fluid and blood are flowing in the opposite
directions and oxygenation of the blood takes place.
15.What is the principle of membrane oxygenator?
Effective oxygenation is obtained when oxygen and blood are running in opposite
directions through a thin porous membrane.
16.What is the principle of film oxygenator?
Here the film of blood is spread on a rotating disc or metal screen and an oxygen
mixture flows over this thin layer of blood.
17.What is the principle of bubble oxygenator?
By bubbling the oxygen through a large column of blood and the making the flow of
blood through a slanting path, the carbon di oxide is removed form the blood
18.Define oxygenator.
In oxygenator mixture of oxygen and 2 to 5 percentage of carbon dioxide is usually
employed to avoid respiratory alkalosis. Every oxygenator should oxygenate upto 5
liters per minute of blood.
19.What are the types of blood pumps?
1.Pulsatile pumps
2.Non pulsatile pumps
20.Define heat exchanger
Heat exchanger is used to regulate the blood temperature and compensate for the heat
exchange in or out of the oxygenato
Unit I
1) Draw the structure of cell & explain the various compositions with their
Structure of Cell & its incredients- Explanation
Ref : Biomedical Instrumentation
- Dr. M. Arumugam
2) Define resting potential & Action potential. Explain how these potentials are generated
in human body.
Resting & Action Potential generation
Polarization & Depolarization of cell
Sodium pump -description
Ref : Biomedical Instrumentation & Measurements
- Leslie Cromwell
Fred J. Weibell
Erich A. Pfeiffer
3) Explain in detail the different types of Electrodes used for biomedical
Depth & Needle electrodes
Surface electrodes
Chemical electrodes
Ref : Biomedical Instrumentation
- Dr. M. Arumugam
4) Describe the different sensors used in biomedicine.
Force transducers
Transducers for Displacement, Velocity, Acceleration
Pressure transducers
Flow transducers
Transducers for digital output
Ref : Biomedical Instrumentation & Measurements
- Leslie Cromwell
Fred J. Weibell
Erich A. Pfeiffer
5)Explain in detail the electrical safety & grounding & isolation techniques.
Physiological effects of Electrical current
Shock hazards from electrical equipment
Methods of accident prevention
Ref : Biomedical Instrumentation & Measurements
- Leslie Cromwell
Fred J. Weibell
Erich A. Pfeiffer
Unit -II
1) With neat diagram explain ECG?
Refer Page No. 122 - 128 in "Bio-medical Instrumentation" by Dr. M. Arumugam.
2) With neat diagram explain EEG?
Refer Page No. 149 - 152 in "Bio-medical Instrumentation" by Dr. M. Arumugam.
3) With neat diagram explain EMG?
Refer Page No. 153 - 156 in "Bio-medical Instrumentation" by Dr. M. Arumugam.
4) With neat diagram explain EOG?
Refer Page No. 156 - 159 in "Bio-medical Instrumentation" by Dr. M. Arumugam.
5) Explain how recorders are selected with high accuracy?
Refer Page No. 159 - 160 in "Bio-medical Instrumentation" by Dr. M. Arumugam.
5) Explain Different lead system for recording ECG.
In standard ECG recording there are 5 electrodes connected to the patient. Right arm,
Left arm, Left leg, Right leg and chest. These electrodes are connected to the input of a
differential amplifier through a lead selector switch.
The recording obtained across different pairs of electrodes results in different waveform
shapes and amplitudes; each lead conveys a certain amount of unique information.
The ecg machine uses the patients right leg as common electrode and the lead selector
connects proper limb or chest electrodes to the diff amplifier input.
The bipolar limb leads are those designated lead I , lead II and lead III and form what is
called Einthoven triangle.
1.leadI : LA is connected to the amplifiers non inverting input, while RA is connected
to the inverting terminal.
2. lead II: The LL is connected to the amplifiers NI input, while RA is connected to the
inverting input.
3. LeadIII: the LL is connected to the NI terminal while LA is connected to the
inverting input.
Lead I: VI = FL - FR
Lead II: VII = FF - FR
Lead III: VIII = FF - FL
VI : the voltage of Lead I
VII : the voltage of Lead II
VII : the voltage of Lead III
FL = potential at the left arm
FR = potential at the left arm
FF = potential at the left arm
Einthoven's Triangle and Law
Einthoven, the father of electrocardiography, visualized the three standard limb leads
enclosing the heart in a triangle, often referred to as Einthoven's triangle Einthoven also found
a relationship between the amplitude of the QRS complexes in each lead, such that lead I +
lead III = lead II (Einthoven's law).
The unipolar limb lead are also known as the augmented limb leads, examine the
composite potential from all three leads simultaneously. In all augmented leads the signals
from two limbs are summed in a resistor network and then applied to the amplifiers inverting
input, while the signal from the remaining limb electrode is applied to the non inverting input.
1. Lead aVR: RA is connected to the noninverting input, while LA and LL are
summed at the inverting terminal.
2. Lead aVL: LA is connected to the noninverting input, while RA and LL are
summed at the inverting input.
3. Lead aVF: LL is connected to the noninverting input , while RA and LA are
summed at the inverting input.
The unipolar chest leads (V1 through V6) are measured with the signals from certain
specified locations on the chest applied to the amplifiers noninverting input, while the
RA, LA and LL signals are summed in a resistor network at the amplifiers inverting
Unit III
1)Explain the different methods of blood pressure measurements in detail.
Indirect measurements
Automated indirect methods
Direct measurements
Ref : Biomedical Instrumentation & Measurements
- Leslie Cromwell
Fred J. Weibell
Erich A. Pfeiffer
2) What are bloodflowmeters? Explain in detail about the ultrasonic
Definition for bloodflowmeter
Ultrasonic bloodflowmeter
Ref : Biomedical Instrumentation & Measurements
- Leslie Cromwell
Fred J. Weibell
Erich A. Pfeiffer
3)Explain in detail about the measurement of heart sounds.
Measurement of heart sound
Ref : Biomedical Instrumentation & Measurements
- Leslie Cromwell
Fred J. Weibell
Erich A. Pfeiffer
4) Describe the measurement of gas volume in detail.
Lung volume & capacities
Mechanical measurements
Instrumentation for measuring the mechanics of breathing
Ref : Biomedical Instrumentation & Measurements
- Leslie Cromwell
Fred J. Weibell
Erich A. Pfeiffer
5)Define pH. Explain in detail the measurements of blood pH with neat sketches.
Definition for pH
pH meter
Ref : Biomedical Instrumentation
- Dr. M. Arumugam
Unit - IV
1) With neat diagram explain X-Ray machine?
Refer Page No. 299 - 303 in "Bio-medical Instrumentation" by Dr. M. Arumugam.
2) With neat diagram explain Computer Tomography?
Refer Page No. 363 - 367 in "Bio-medical Instrumentation" by Dr. M. Arumugam.
3) With neat diagram explain Ultrasonography?
Refer Page No. 388- 389 in "Bio-medical Instrumentation" by Dr. M. Arumugam.
4) With neat diagram explain MRI?
Refer Page No. 399 - 400 in "Bio-medical Instrumentation" by Dr. M. Arumugam.
5) With neat diagram explain Laser Instrumentation?
Refer Page No. 351 - 355 in "Bio-medical Instrumentation" by Dr. M. Arumugam.
Unit V
1) What are pacemakers? Explain in detail the demand pacemaker with neat
Definition for pacer
Demand pacemaker
Ref : Biomedical Instrumentation
- Dr. M. Arumugam
2)What are defibrillators? Explain in detail any two types of defibrillators with neat
Definition for defibrillator
DC defibrillator
Sync. DC defibrillator
Ref : Biomedical Instrumentation
- Dr. M. Arumugam
3)With neat diagram, explain in detail about the muscle stimulator.
Refer in "Bio-medical Instrumentation" by Dr. M. Arumugam.
4) With neat diagram explain Heart - Lung machine?
Refer Page No. 202 - 205 in "Bio-medical Instrumentation" by Dr. M. Arumugam.
5) With neat diagram explain Endoscope?
Refer Page No. 356 - 358 in "Bio-medical Instrumentation" by Dr. M. Arumugam.
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