Answer: d [Reason:] The obstetrician is faced with the problem of having very few parameters available on which to base a diagnosis of foetal well-being or distress. In most cases, the condition of the foetus is assessed by studying the blood flow in the foetal heart and its heart rate. The foetal heart rate (FHR) yields important information about the status of the foetus, and therefore, has become a widely studied parameter in maternity cases.

Answer: b [Reason:] False, Foetal heart rate monitoring in the labour ward has generally been carried out on an intermittent basis. It has been traditional to listen to the foetal heart sounds at intervals of up to every 15 minutes. This is done by using the Pinard stethoscope.

Answer: c [Reason:] Foetal heart rate monitoring in the labour ward has generally been carried out on an intermittent basis. It has been traditional to listen to the foetal heart sounds at intervals of up to every 15 minutes. This is done by using the Pinard stethoscope.

Answer: c [Reason:] An assessment of the condition of the foetus can be made during labour from the foetal heart action. Simultaneously, recording beat-to-beat foetal heart rate and uterine activity provides basic information for assessing the compensatory potential of the foetal circulatory system.

Answer: b [Reason:] The instrument which carries out a continuous and simultaneous recording of the instantaneous foetal heart rate and labour activity is called cardiotocograph. In addition to detecting long-term bradycardia or tachycardia, this instrument helps in the evaluation of foetal heart rate response of the undisturbed circulatory system and response stimulated by uterine contractions.

Answer: d [Reason:] Cardiotocographs are designed to measure and record foetal heart rate on a beat-to-beat basis rather than on an average basis. Normally, an accuracy of measurement may be 2–3% for classification of responses. Sensitivity of 20 bpm/cm of recording chart allows adequate reading of the recorded FHR.

Answer: c [Reason:] Tocodynamometry is an indirect method to measure uterine contractionin cardiotographic monitoring during labour in which tocotonometer is used to sense changes in uterine tension transmitted to abdominal skin surface.

Answer: d [Reason:] Abdominal foetal electrocardiogram,foetal phonocardiogram and Ultrasound technique are indirect methods of measuring foetal heart rate where as Foetal ECG with scalp electrode is direct method as in it spiral,clip or suction electrode is attached to the presenting part of foetus.

Answer: b [Reason:] False, Cardiotocographs are designed to measure and record foetal heart rate on a beat-to-beat basis rather than on an average basis. Normally, an accuracy of measurement may be 2–3% for classification of responses.

Answer: b [Reason:] Cardiotocographs are designed to measure and record foetal heart rate on a beat-to-beat basis rather than on an average basis. Normally, an accuracy of measurement may be 2–3% for classification of responses.

Answer: a [Reason:] Quartz is the most stable natural crystal with high mechanical and thermal stability and has voulme resistivity higher than 10^4 ohm-cm and small internal electric loss. Barium titanate ceramic is a ferroelectric crystal and has small voltage output. Aluminium is not a piezo-electric material.

Answer: b [Reason:] Piezo-electricity is pressure electricity. The piezo electric effect is a property of natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation.

Answer: a [Reason:] It is True. The piezo electric effect is a property of natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation. On applying electricity to the piezo-electric material mechanical deformation occurs in the material.

Answer: d [Reason:] The motion of diaphragm is measured in terms of electric signals. Tourmaline , barium titanate and zirconate titanate are piezo electric materials. Phosphor bronze is used to make diaphragm to measure pressure.

Answer: d [Reason:] The principle behind strain gaude is the variable resistance. A linear relation exists between the deformation and electrical resistance of a suitable selected gauge over a specified range. The transducer is based upon the changed in resistance of a wire produced due to small mechanical displacement.

Answer: a [Reason:] It is True. On applying pressure to piezo-electric crystal, electricity is generated. The piezo electric effect is a property of natural crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation. Thus, piezo-electricity is pressure electricity.

Answer: c [Reason:] Gauge factor gives information on the expected resistance change or output signal at maximum permissible elongation.the gauge factor determines to a large extent the sensitivity of the wire when it is made into a practical strain gauge. The figure of merit which describes the overall behaviour of the wire under stress is determined from the gauge factor of the wire.

Answer: d [Reason:] Gauge factor is defined as (incremental change in resistance due to stress/resistance of an unstretched wire)*(unstretched length of wire/incremental change in length). Gauge factor gives information on the expected resistance change or output signal at maximum permissible elongation.the gauge factor determines to a large extent the sensitivity of the wire when it is made into a practical strain gauge.

Answer: c [Reason:] The third lead is in series with the power supply and is therefore independent of bridge balance. Compensation for temperature variation in the leads can be provided by using three lead method. In this method two of the leads are in the adjacent legs of the bridge which cancels their resistance changes and does not disturb the bridge balance.

Answer: d [Reason:] Strain gauge is used to measure pressure. There are two type of strain gauges. Bounded strain gauge and unbounded strain gauge. Its working principle is change in resistance.Mostly used to measure the arterial and venous blood pressure in the body.

Answer: a [Reason:] The total amount of glomerular filtrate is about 180 litres per day, whereas the amount of urine formed from it is only 1–1.5l. This means that very large amounts of water, and other substances, are re-absorbed by the kidney tubules.

Answer: c [Reason:] The amount of urine formed by an average kidney in one day is 1-1.5 L. The total amount of glomerular filtrate is about 180 litres per day. Very large amounts of water, and other substances, are re-absorbed by the kidney tubules.

Answer: c [Reason:] The re-absorption is partly an automatic process, because the absorption of water is accurately controlled by the anti-diuretic hormone of the pituitary gland, in relation to the body’s need for water. The absorption of electrolytes such as sodium and potassium is partly controlled by the supra-renal gland and the concentration of others, like chloride and bicarbonate, is related to the acid-base balance.

Answer: b [Reason:] The total blood flow through the kidneys is about 1200 ml/min. The absorption of electrolytes such as sodium and potassium is partly controlled by the supra-renal gland and the concentration of others, like chloride and bicarbonate, is related to the acid-base balance. Some of the re-absorption from the glomerular filtrate is also a passive, automatic process of diffusion depending upon pressure gradients.

Answer: c [Reason:] The total extra-cellular fluid amounts to about 15 litres. Some of the re-absorption from the glomerular filtrate is also a passive, automatic process of diffusion depending upon pressure gradients. The total blood flow through the kidneys is about 1200 ml/min.

Answer: b [Reason:] It is false. Kidney plays an important role in maintaining the acid-base balance. . The water and electrolyte content of the blood plasma and, therefore, indirectly of the extra-cellular fluid are closely controlled by the kidneys. The blood plasma and the extra-cellular fluid are in equilibrium with each other and, therefore, an amount of blood equivalent to all the extra-cellular fluid can pass through the kidneys once every 15 minutes.

Answer: a [Reason:] The symptoms and signs of profound renal malfunction are known as uremia, meaning urine in the blood. Since most urinary contents are water-soluble, they reach high concentrations in blood, and result in deranged body parts and their physiology.

Answer: c [Reason:] Chronic renal failure results in changes in the body fluids which occur due to a progressive decrease in the number of functioning nephrons. With the decrease in functional nephrons, the clearance of urea, creatinine and other metabolic waste products will decrease proportionally. In consequence, the plasma concentrations of these substances will rise.

Answer: a [Reason:] Uremia is the clinical state resulting from renal failure. The signs and symptoms of uremia are extremely diverse and frequently appear to point to disease of other organs. Uremia affects every organ of the body as certain substances that accumulate in uremia are clearly toxic.

Answer: a [Reason:] It is true. The dialysate is an electrolyte solution of suitable composition and the dialysis takes place across a membrane of cellophane. The return of the dialyzed blood is by another plastic tube to an appropriate vein.

Answer: c [Reason:] The blood constitutes 5–10% of the total body weight and in the average adult, it amounts to 5–6 l. Blood consists of corpuscles suspended in a fluid called plasma in the proportion of 45 parts of corpuscles (cells) to 55 parts of plasma.

Answer: d [Reason:] The percentage of cells in the blood is called the haematocrit value or packed cell volume (PCV). The majority of the corpuscles in blood are red blood cells (erythrocytes), others being white blood cells (leucocytes) and platelets (thrombocytes).

Answer: a [Reason:] Erythrocytes (Red Blood Cells): Red blood cells have the form of a bi-concave disc with a mean diameter of about 7.5 m and thickness of about 1.7 m. The mean surface area of the cell is about 134mm2. There are about 5.5 million of them in every cubic millimetre of blood in men and nearly 5 million in women.

Answer: c [Reason:] In the whole body, there are about 25 billion erythrocytes and they are constantly being destroyed and replaced at a rate of about 9000 million per hour. The normal red cell lasts approximately 120 days before it is destroyed.

Answer: c [Reason:] The erythrocytes have no nucleus. They are responsible for carrying oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. Anaemia (reduction in the oxygen carrying capacity of blood) can develop from a change in the number, volume or Hb concentration of erythrocytes, caused by bone marrow dysfunction resulting in the poor production rate of RBCs.

Answer: b [Reason:] Leucocytes form the defence mechanism of the body against infection. They are of two main types: the neutrophils and the lymphocytes. Neutrophils ingest bacteria and lymphocytes are concerned with immunological response.

Answer: a [Reason:] Platelets are usually tiny, round, oblong or irregularly shaped cells of the blood with an average diameter of approximately 2 m. They play an important role in the blood coagulation process. There are usually 250,000–750,000 platelets in every cubic mm of blood.

Answer: d [Reason:] There are three methods of cell counting: i) Microscopic method, ii) Automatic optical method, iii) Electrical conductivity method.

Answer: b [Reason:] Agoston and Zillich (1971) compared the results of microscopic counting with those made by electronic counters. It may be observed that instead of the + 0r – 20% measuring accuracy in microscopic counting, the electronic counters can provide an accuracy of + or – 3%.

Answer: d [Reason:] The method is based on collecting scattered light from the blood cells and converting it into electrical pulses for counting. A sample of dilute blood (1:500 for white cells and 1:50,000 for red cells) is taken in a glass container. It is drawn through a counting chamber in which the blood stream is reduced in cross-section by a concentric high velocity liquid sheath.

Answer: c [Reason:] Instruments based on optical technique take about 30 s for completing the count. An accuracy of 2% is attainable. The instruments require about 1 ml of blood sample.

Answer: d [Reason:] f/l = Femolitres

1f/l = 10^-15.

Answer: b [Reason:] It can be calculated if PCV and Hb per dl are known. For example, if PCV is 0.45 and there are 15 g Hb per dl of blood, then
MCHC = (15 /0.45) g/dl
= 33.3 g/dl

Answer: c [Reason:] Platelet Distribution Width (PDW): This index is related to the size range covered by those platelets lying between the sixteenth and eighty fourth percentile. This is the conventional geometric standard deviation of the mean platelet size and is derived from the distribution curve based on the data in a 64-channel pulse height analyzer.

Answer: a [Reason:] Instruments based on this automatic optical technique take about 30 s for completing the count. An accuracy of 2% is attainable. The instruments require about 1 ml of blood sample.

Answer: a [Reason:] An apexcardiograph records the chest-wall movements over the apex of the heart. These movements are in the form of vibrations having a frequency range of 0.1 to about 20 Hz.

Answer: b [Reason:] False, The transducer required for recording these movements in apexcardiograph is similar to that employed for a phonocardiograph (PCG) but which has a frequency response much below the audio range. It can be an aircoupled microphone or a contact microphone. They are further categorized into crystal type or dynamic type based on their principle of operation. The crystal microphone contains a wafer of piezo-electric material, which generates potentials when subjected to mechanical stresses due to heart sounds.The dynamic type microphone consists of a moving coil having a fixed magnetic core inside it. The coil moves with the heart sounds and produces a voltage because of its interaction with the magnetic flux.

Answer: b [Reason:] A ballistocardiograph is a machine that records the movement imparted to the body with each beat of the heart cycle. These movements occur during the ventricular contraction of the heart muscle when the blood is ejected with sufficient force.

Answer: b [Reason:] In BCG, the patient is made to lie on a table top which is spring suspended or otherwise mounted to respond to very slight movements along the head axis. Sensing devices are mounted on the table to convert these movements into corresponding electrical signals. The sensors usually are piezo-electric crystals, resistive elements or permanent magnets, moving with respect to fixed
coils.

Answer: b [Reason:] Electro-oculography is the recording of the bio-potentials generated by the movement of the eyeball. The EOG potentials are picked up by small surface electrodes placed on the skin near the eye.

Answer: c [Reason:] Electro-oculography is the recording of the bio-potentials generated by the movement of the eyeball. The EOG potentials are picked up by small surface electrodes placed on the skin near the eye.

Answer: c [Reason:] An apexcardiograph records the chest-wall movements over the apex of the heart. These movements are in the form of vibrations having a frequency range of 0.1 to about 20 Hz.

Answer: d [Reason:] It is found that an electrical potential exists between the cornea and the back of the eye. This potential changes when the eye is illuminated. The process of recording the change in potential when light falls on the eye is called electroretinography.

Answer: a [Reason:] True, ERG potentials can be recorded with a pair of electrodes. One of the electrodes is mounted on a contact lens and is in direct contact with the cornea and the other electrode is placed on the skin adjacent to the outer corner of the eye as it is found that an electrical potential exists between the cornea and the back of the eye. This potential changes when the eye is illuminated. A reference electrode may be placed on the forehead.

Answer: a [Reason:] The apexcardiograph has limited applications. It is, however, useful in the diagnosis of the enlargement of the heart chambers and some type of valvular disorders.