MAHALAKSHMImahalakshmiengineeringcollege.com/pdf/eee/VIIsem/EI2311/UNIT 1.pdf · EI2311- BIOMEDICAL INSTRUMENTATION IV YR/ VII SEM EEE MAHALAKSHMI ENGINEERING COLLEGE TIRUCHIRAPALLI-

EI2311- BIOMEDICAL INSTRUMENTATION IV YR/ VII SEM EEE

MAHALAKSHMI

ENGINEERING COLLEGE

TIRUCHIRAPALLI- 621213.

QUESTION BANK

SEMESTER : VII DEPARTMENT: EEE

SUBJECT NAME: BIOMEDICAL INSTRUMENTATION SUBJECT CODE: EI2311

UNIT 1- PHYSIOLOGY & TRANSDUCERS

PART A (2 Marks)

1. Distinguish absolute & relative refractory period.(NOV 2007)

Following the generation of action potential, there is a brief period of time during which the cell

cannot respond to any new stimulus. This period is called absolute refractory period, lasting

about 1 msec in nerve cells. Following the absolute refractory period, there occurs a relative

refractory period, during which another action potential can be triggered, but a stronger

stimulation is required. In nerve cells, the relative refractory period lasts several milliseconds.

2. What is a spinal cord? (NOV 2007)

The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends

from the brain (the medulla oblongata specifically). The brain and spinal cord together make up

the central nervous system (CNS). The spinal cord begins at the occipital bone and extends down

to the space between the first and second lumbar vertebrae; it does not extend the entire

length of the vertebral column. The spinal cord functions primarily in the transmission of neural

signals between the brain and the rest of the body but also contains neural circuits that can

independently control numerous reflexes and central pattern generators. The spinal cord has

three major functions: as a conduit for motor information, which travels down the spinal cord,

as a conduit for sensory information in the reverse direction, and finally as a center for

coordinating certain reflexes.

3. Define action potential. (NOV 2011)

When a section of a cell membrane is excited by the flow of ionic current or by some form of

externally applied energy, the membrane changes its characteristics & begins to allow some of

the sodium ions to enter. This movement of sodium ions into the cell constitutes an ionic current

flow that further reduces the barrier of the membrane to sodium ions. The net result is avalanche

effect in which sodium ion rush into the cell to try to reach a balance with the ions outside. At the

same time potassium ions, which were in higher concentration inside the cell during the resting

state, 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 inside due to the imbalance of potassium ions. This

potential is known as action potential & is approximately equal to +20mV. A cell that has been

excited & that displays an action potential is said to be depolarized, & the process of changing

from the resting state to the action potential is known as depolarization.

4. What are active & passive transducers?(NOV 2011)

http://en.wikipedia.org/wiki/Nervous_tissuehttp://en.wikipedia.org/wiki/Gliahttp://en.wikipedia.org/wiki/Brainhttp://en.wikipedia.org/wiki/Medulla_oblongatahttp://en.wikipedia.org/wiki/Central_nervous_systemhttp://en.wikipedia.org/wiki/Occipital_bonehttp://en.wikipedia.org/wiki/Lumbar_vertebraehttp://en.wikipedia.org/wiki/Vertebral_columnhttp://en.wikipedia.org/wiki/Brainhttp://en.wikipedia.org/wiki/Neural_circuithttp://en.wikipedia.org/wiki/Reflexhttp://en.wikipedia.org/wiki/Central_pattern_generator


5. What is bioelectric potential? (MAY 2012)

Certain systems of the body generate their own monitoring signals, which convey the useful

information about the function they represent. These signals are called as Bioelectric Potentials.

They are actually ionic voltages produced as a result of electrochemical activity of certain special

type of cells. The transducers convert these ionic potential to electric voltages. These natural

signals can be measured, monitored & aid the physician in diagnosis & treatment of various

diseases.

6. What is propagation of action potential? (MAY 2012)

Same as Q3

7. What are resting & action potentials? (NOV 2012)

Same as Q3 & Q10

8. What is a neuron? Define the various parameter associated with it. (NOV 2012)

The basic unit of nervous system is the neuron. The neuron is the single cell with a cell body,

sometimes called as soma, one or more input fibers called dendrites & a long transmitting fiber

called as axon. The axon branches near its ending into two or more terminals. The portion of the

axon immediately adjacent to the cell body is called axon hillock. This is the point at which the

action potentials are usually generated. Branches that leave the main axon are often called

collaterals. The axons & dendrites are coated with a fatty insulating substance called as myelin.

The coating is called as myelin sheath. In some cases the myelin sheath is interrupted at rather

intervals by the nodes of ranvier, which helps the speed of transmission of of information along

the nerves. Outside of the central nervous system, the myelin sheath is surrounded by an

insulating layer called as neurilemma. This layer is thinner than the myelin sheath & continuous

over the nodes of ranvier, is made up of thin cells called Schwann cells.

9. Classify the biomedical instrumentation.(MAY 2013)

o Measuring Instruments.

o Audiometer

o Blood cell counter

o Blood Pressure meter

o Blood PH meter

o Blood flow meter

o Digital BP meter

o GSR meter

o Stethoscope

10. Define resting potential. (MAY 2013) First the concentration of sodium cells inside the cell becomes much lower than in the intercellular

fluid outside. Since the sodium ions are positive, this would tend to make the outside of the cell

more positive than inside. Second in an attempt to balance the electric charge, additional

potassium ions which are also positive enter the cell, causing a higher concentration of potassium

on the inside than on the outside. This charge balance cannot be achieved, however, because of

the concentration imbalance of potassium ions. Equilibrium is reached with a potential difference

across the membrane, negative on the inside & positive on the outside. This membrane potential


is called the resting potential of the cell & is maintained until some kind of disturbance upsets the

equilibrium.

11. What is meant by cell?

The basic living unit of the body is cell. The function of organs and other structure of the body

are understood by cell organization.

12. State the applications of medical instrumentation system?

To design experiments & clinical studies.

To summarize, explore, analyze & present data

To draw inferences from data by estimation or hypothesis testing

To evaluate diagnostic procedure

To assist clinical decision making.

13. What is meant by measurement?

Measurement is an act or the result of comparison between the quantity and a

predefined standard.

14. Mention the basic requirements of measurement.

The standard used for comparison purpose must be accurately defined and should be

commonly accepted. The apparatus used and the method adopted must be provable.

15. What are the applications of piezo electric sensors?

in cardiology

In phonocardiology

in blood pressure measurement

in measuring physiological accelerations

16. Define transducers.

Transducers are defined as a device which when actuated, transforms energy from one

form to another. Generally, any physical parameters are converted into electrical form.

17. Name the parameters that dictate the transducer capability

Linearity

Repeatability

Resolution and

Reliability

18. Define sensitivity

Sensitivity is defines as the electrical output per unit change in the physical parameter.

High sensitivity is generally desirable for a transducer.

19. Classify electrical transducers?

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.

20. Name the 2 parts of a transducer

Sensing element


Transduction element

11. What is electrode potential (or) half cell potential?

The interface of metallic ion solution with their associated metal results in an electrode

potential.

21. What are the characteristics of resting potential?

The value of potential is maintained as constant. It depends on temperature.

Permeability varies.

22. Define the process of sodium pump.

It is an active process, called a sodium pump in which the sodium ions are quickly

transported to the outside of the cell & the cell again becomes polarized and assumes its resting

potential.

23. Define circulatory system

It is 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.

24. Define heart, lung?

Heart is 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.

25. Define circulation and respiration?

We can define 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.

26. Give the applications of measurement systems.

The instruments and measurement systems are used for

Monitoring of processes and operations.

Control of process and operations.

Experimental engineering analysis.

27. List the functional elements of the measurement systems.

Primary sensing element.

Variable conversion element and

Data processing element.

28. What is radiation thermometry?

The basis of radiation thermometry is that there is a known relationship between the

surface temperature of an object and its radiant power. This principle makes it possible to measure

the temperature of a body without physical contact to it.

29. What is signal conditioning?

The performing of non-linear processes like modulation, detection, sampling, filtering,

chopping and clipping etc. on the signal to bring it to desired form is called signal conditioning.

30. What is meant by Resting Potential?

Equilibrium is reached with a potential difference across the membrane such that

negative on inside and positive on outside. This membrane potential caused by the different

concentration of irons is called Resting Potential.

31. 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.

PART B (8 & 16 Marks)

1. With relevant graph explain the relationship between the action potential & muscle contraction.

(NOV 2007)

SOURCES OF BIOELECTRIC POTENTIAL:

Certain systems of the body generate their own monitoring signals, which convey the useful

information about the function they represent. These signals are called as Bioelectric Potentials.

They are actually ionic voltages produced as a result of electrochemical activity of certain special

type of cells. The transducers convert these ionic potential to electric voltages. These natural

signals can be measured, monitored & aid the physician in diagnosis & treatment of various

diseases.

RESTING & ACTION POTENTIAL:

Certain types of cells within the body, such as nerve & muscle cells are encased in a semi

permeable membrane that permits some substances to pass through the membrane while others

kept out.

Surrounding the cells of the body are the body fluids. These fluids are conductive solutions

containing charged atoms known as ions. These principal ions are sodium Na+, potassium K

+ &

chloride C-. the membrane of the excitable cells readily permits entry of potassium & chloride

ions but effectively blocks the entry of sodium ions. Since the various ions seek a balance

between the inside of the cell & the outside, both according to the concentration of electric

charge, the inability of the sodium to penetrate the membrane results in two conditions.

First the concentration of sodium cells inside the cell becomes much lower than in the intercellular

fluid outside. Since the sodium ions are positive, this would tend to make the outside of the cell

more positive than inside. Second in an attempt to balance the electric charge, additional

potassium ions which are also positive enter the cell, causing a higher concentration of potassium

on the inside than on the outside. This charge balance cannot be achieved, however, because of

the concentration imbalance of potassium ions. Equilibrium is reached with a potential difference

across the membrane, negative on the inside & positive on the outside.

This membrane potential is called the resting potential of the cell & is maintained until some kind

of disturbance upsets the equilibrium. Since the membrane potential measurement is made from

inside the cell with respect to the body fluids, the resting potential is negative & ranges from -60

to -100mV. A cell in resting state is said to be polarized.

When a section of a cell membrane is excited by the flow of ionic current or by some form of

externally applied energy, the membrane changes its characteristics & begins to allow some of

the sodium ions to enter. This movement of sodium ions into the cell constitutes an ionic current

flow that further reduces the barrier of the membrane to sodium ions. The net result is avalanche

effect in which sodium ion rush into the cell to try to reach a balance with the ions outside. At the

same time potassium ions, which were in higher concentration inside the cell during the resting

state, 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 inside due to the imbalance of potassium ions. This

potential is known as action potential & is approximately equal to +20mV. A cell that has been


excited & that displays an action potential is said to be depolarized, & the process of changing

from the resting state to the action potential is known as depolarization.

Once the rush of sodium ions through the cell membrane has stopped, a new state of equilibrium

is reached. the ionic currents that lowered the barrier to sodium ions are no longer present & the

membrane reverts back to its original selectively permeable condition, whereas the passage of

sodium ions from the outside to the inside of the cell is again blocked. It would take a long time

for the resting potential to develop again. But by an active process called as sodium pump, the

sodium ions are quickly transported to the outside of the cell, & the cell again becomes polarized

& assumes its resting potential. This process is called is called repolarization. The rate of

pumping is directly proportional to the sodium concentration in the cell.

The above figure shows the action potential waveform, beginning at the resting potential,

depolarizing & returning to the resting potential after repolarization

Following the generation of action potential, there is a brief period of time during which the cell

cannot respond to any new stimulus. This period is called absolute refractory period, lasting about

1 msec in nerve cells. Following the absolute refractory period, there occurs a relative refractory

period, during which another action potential can be triggered, but a stronger stimulation is

required. In nerve cells, the relative refractory period lasts several milliseconds.

2. Explain in detail how pulsatile blood volume changes can be measured using photoelectric type

resistive transducer. (NOV 2007)


3. Explain in detail central & peripheral nervous system. (NOV 2007)

THE NERVOUS SYSTEM

The nervous system is one which is responsible for the task of controlling the various functions of

the body & coordinating them into integrated living organisms. The basic unit of nervous system

is the neuron. The neuron is the single cell with a cell body, sometimes called as soma, one or

more input fibers called dendrites & a long transmitting fiber called as axon. The axon branches

near its ending into two or more terminals

The portion of the axon immediately adjacent to the cell body is called axon hillock. This is the

point at which the action potentials are usually generated. Branches that leave the main axon are

often called collaterals. The axons & dendrites are coated with a fatty insulating substance called

as myelin. The coating is called as myelin sheath. In some cases the myelin sheath is interrupted

at rather intervals by the nodes of ranvier, which helps the speed of transmission of of information

along the nerves. Outside of the central nervous system, the myelin sheath is surrounded by an

insulating layer called as neurilemma. This layer is thinner than the myelin sheath & continuous

over the nodes of ranvier, is made up of thin cells called Schwann cells.

Both axons & dendrites are called as nerve fibers & a bundle of individual nerve fibber is called as

nerve. Nerves that carry information from various parts of the body to the brain is called afferent

nerves & that from brain to various parts of the body is called efferent nerves.

Central Nervous system (CNS)


The brain is an enlarged collection of cell bodies & fibers located inside the skull, where it is well

protected from physical, temperature & chemical shock. The lower end of the brain connects with

the spinal cord, which also contains many cell bodies & fibers. Brain & spinal cord together forms

the central nervous system.

Cell bodies & small fibers in fresh brain are gray in color & are called gray matter, whereas the

myelin coating of larger fibers has a white appearance & are called as white matter. Collection of

neuronal cell bodies within the central nervous system is called nuclei; whereas the collection

outside the central nervous system is called ganglia. The central nervous system is generally said

to have bilateral symmetry.

Nerve fibers outside the CNS are called peripheral nerves. Afferent peripheral nerves that brings

sensory information to the CNS is called sensory nerves, whereas the the efferent nerves that

control the motor functions of the muscles are called as motor nerves.

The interconnection between neurons is called as synapses. All synapses occur at or near cell

bodies. In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to

pass an electrical or chemical signal to another cell. Synapses are essential to neuronal function:

neurons are cells that are specialized to pass signals to individual target cells, and synapses are

the means by which they do so. At a synapse, the plasma membrane of the signal-passing

neuron (the presynaptic neuron) comes into close apposition with the membrane of the target

(postsynaptic) cell. Both the presynaptic and postsynaptic sites contain extensive arrays

of molecular machinery that link the two membranes together and carry out the signaling process.

In many synapses, the presynaptic part is located on an axon, but some presynaptic sites are

located on a dendrite or soma.Astrocytes also exchange information with the synaptic neurons,

responding to synaptic activity and, in turn, regulating neurotransmission.

There are two fundamentally different types of synapses:

In a chemical synapse, electrical activity in the presynaptic neuron is converted (via the

activation of voltage-gated calcium channels) into the release of a chemical called

aneurotransmitter that binds to receptors located in the plasma membrane of the postsynaptic

http://en.wikipedia.org/wiki/Nervous_systemhttp://en.wikipedia.org/wiki/Neuronhttp://en.wikipedia.org/wiki/Cell_(biology)http://en.wikipedia.org/wiki/Plasma_membranehttp://en.wikipedia.org/wiki/Molecular_biologyhttp://en.wikipedia.org/wiki/Axonhttp://en.wikipedia.org/wiki/Dendritehttp://en.wikipedia.org/wiki/Soma_(biology)http://en.wikipedia.org/wiki/Astrocytehttp://en.wikipedia.org/wiki/Neurotransmissionhttp://en.wikipedia.org/wiki/Chemical_synapsehttp://en.wikipedia.org/wiki/Voltage-dependent_calcium_channelhttp://en.wikipedia.org/wiki/Neurotransmitterhttp://en.wikipedia.org/wiki/Neurotransmitter_receptor


cell. The neurotransmitter may initiate an electrical response or a secondary messenger pathway

that may either excite or inhibit the postsynaptic neuron. Chemical synapses can be classified

according to the neurotransmitter released: glutamatergic (excitatory), GABAergic (inhibitory),

cholinergic (e.g. vertebrate neuromuscular junction) and adrenergic (releasing norepinephrine).

Because of the complexity of receptorsignal transduction, chemical synapses can have complex

effects on the postsynaptic cell.

In an electrical synapse, the presynaptic and postsynaptic cell membranes are connected by

special channels called gap junctions that are capable of passing electric current, causing voltage

changes in the presynaptic cell to induce voltage changes in the postsynaptic cell. The main

advantage of an electrical synapse is the rapid transfer of signals from one cell to the next

Peripheral Nervous System (PNS)

The main function of PNS is to connect the CNS to the organs & limbs of the body. The PNS

consists of several subsystems,

1. Somatic sensory nervous system – system of afferent nerves that carry sensory information from

the sensors on the skin to the brain.

2. Auditory nervous system – carries information from the auditory sensors in the ears to the brain.

3. Visual pathways – carry sensory information from eyes to the brain.

4. Autonomic nervous system – which involves emotional responses & controls smooth muscle in

various parts of the body, heart muscle & secretion of a number of glands.

Sympathetic nervous system – speeds up the heart, causes secretion of some glands &

inhibits other body functions. In general it tends to mobilize the body for emergencies.

Parasympathetic nervous system – which tends to slow the heart & controls the

contraction & secretion of the stomach. In general it tends to conserve & store bodily

resources.

Structure of Brain & Spinal Cord

http://en.wikipedia.org/wiki/Neuromuscular_junctionhttp://en.wikipedia.org/wiki/Norepinephrinehttp://en.wikipedia.org/wiki/Signal_transductionhttp://en.wikipedia.org/wiki/Electrical_synapsehttp://en.wikipedia.org/wiki/Gap_junction

EI2311/ BIOMEDICAL INSTRUMENTATION VII SEM EEE

The human brain has the same general structure as the brains of other mammals, but has a

more developed cortex than any other. Large animals such as whales and elephants have larger

brains in absolute terms, but when measured using the encephalization quotient which

compensates for body size, the human brain is almost twice as large as the brain of

the bottlenose dolphin, and three times as large as the brain of a chimpanzee. Much of the

expansion comes from the part of the brain called the cerebral cortex, especially the frontal lobes,

which are associated with executive functions such as self-control, planning, reasoning,

and abstract thought. The portion of the cerebral cortex devoted to vision is also greatly enlarged

in humans.

The human cerebral cortex is a thick layer of neural tissue that covers most of the brain. This

layer is folded in a way that increases the amount of surface that can fit into the volume available.

The pattern of folds is similar across individuals, although there are many small variations. The

cortex is divided into four "lobes", called the frontal lobe, parietal lobe, temporal lobe,

and occipital lobe. (Some classification systems also include a limbic lobe and treat the insular

cortex as a lobe.) Within each lobe are numerous cortical areas, each associated with a particular

function such as vision, motor control, language, etc. The left and right sides of the cortex are

broadly similar in shape, and most cortical areas are replicated on both sides. Some areas,

though, show strong lateralization, particularly areas that are involved in language. In most

people, the left hemisphere is "dominant" for language, with the right hemisphere playing only a

minor role. There are other functions, such as spatiotemporal reasoning, for which the right

hemisphere is usually dominant.

Despite being protected by the thick bones of the skull, suspended in cerebrospinal fluid, and

isolated from the bloodstream by the blood–brain barrier, the human brain is susceptible to

damage and disease. The most common forms of physical damage are closed head injuries such

as a blow to the head, a stroke, or poisoning by a variety of chemicals that can act

as neurotoxins. Infection of the brain, though serious, is rare due to the biological barriers which

protect it. The human brain is also susceptible to degenerative disorders, such as Parkinson's

disease, multiple sclerosis, and Alzheimer's disease. A number of psychiatric conditions, such

asschizophrenia and depression, are thought to be associated with brain dysfunctions, although

the nature of such brain anomalies is not well understood.

Scientifically, the techniques that are used to study the human brain differ in important ways from

those that are used to study the brains of other mammals. On the one hand, invasive techniques

such as inserting electrodes into the brain, or disabling parts of the brain in order to examine the

effect on behavior, are used with non-human species, but for ethical reasons, are generally not

performed with humans. On the other hand, humans are the only subjects who can respond to

complex verbal instructions. Thus, it is often possible to use non-invasive techniques such

as functional neuroimaging or EEG recording more productively with humans than with non-

humans. Furthermore, some of the most important topics, such as language, can hardly be

studied at all except in humans. In many cases, human and non-human studies form essential

complements to each other. Individual brain cells (except where tissue samples are taken for

biopsy for suspected brain tumors) can only be studied in non-humans; complex cognitive tasks

can only be studied in humans. Combining the two sources of information to yield a complete

functional understanding of the human brain is an ongoing challenge for neuroscience.

The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends

from the brain (the medulla oblongata specifically). The brain and spinal cord together make up

the central nervous system (CNS). The spinal cord begins at the occipital bone and extends down

to the space between the first and second lumbar vertebrae; it does not extend the entire length

of the vertebral column. It is around 45 cm (18 in) in men and around 43 cm (17 in) long in

women. Also, the spinal cord has a varying width, ranging from 1/2 inch thick in the cervical and

lumbar regions to 1/4 inch thick in the thoracic area. The enclosing bony vertebral

column protects the relatively shorter spinal cord. The spinal cord functions primarily in the

transmission of neural signals between the brain and the rest of the body but also contains neural

circuits that can independently control numerous reflexes and central pattern generators. The

http://en.wikipedia.org/wiki/Brainhttp://en.wikipedia.org/wiki/Mammalhttp://en.wikipedia.org/wiki/Encephalization_quotienthttp://en.wikipedia.org/wiki/Bottlenose_dolphinhttp://en.wikipedia.org/wiki/Chimpanzeehttp://en.wikipedia.org/wiki/Cerebral_cortexhttp://en.wikipedia.org/wiki/Frontal_lobehttp://en.wikipedia.org/wiki/Executive_functionshttp://en.wikipedia.org/wiki/Self-controlhttp://en.wikipedia.org/wiki/Planninghttp://en.wikipedia.org/wiki/Reasonhttp://en.wikipedia.org/wiki/Abstractionhttp://en.wikipedia.org/wiki/Nervous_tissuehttp://en.wikipedia.org/wiki/Frontal_lobehttp://en.wikipedia.org/wiki/Parietal_lobehttp://en.wikipedia.org/wiki/Temporal_lobehttp://en.wikipedia.org/wiki/Occipital_lobehttp://en.wikipedia.org/wiki/Limbic_lobehttp://en.wikipedia.org/wiki/Insular_cortexhttp://en.wikipedia.org/wiki/Insular_cortexhttp://en.wikipedia.org/wiki/Cortical_areahttp://en.wikipedia.org/wiki/Lateralization_of_brain_functionhttp://en.wikipedia.org/wiki/Spatial%E2%80%93temporal_reasoninghttp://en.wikipedia.org/wiki/Cerebrospinal_fluidhttp://en.wikipedia.org/wiki/Blood%E2%80%93brain_barrierhttp://en.wikipedia.org/wiki/Closed_head_injuryhttp://en.wikipedia.org/wiki/Human_headhttp://en.wikipedia.org/wiki/Strokehttp://en.wikipedia.org/wiki/Neurotoxinhttp://en.wikipedia.org/wiki/Parkinson%27s_diseasehttp://en.wikipedia.org/wiki/Parkinson%27s_diseasehttp://en.wikipedia.org/wiki/Multiple_sclerosishttp://en.wikipedia.org/wiki/Alzheimer%27s_diseasehttp://en.wikipedia.org/wiki/Psychiatric_conditionhttp://en.wikipedia.org/wiki/Schizophreniahttp://en.wikipedia.org/wiki/Major_depressive_disorderhttp://en.wikipedia.org/wiki/Functional_neuroimaginghttp://en.wikipedia.org/wiki/Electroencephalographyhttp://en.wikipedia.org/wiki/Neurosciencehttp://en.wikipedia.org/wiki/Nervous_tissuehttp://en.wikipedia.org/wiki/Gliahttp://en.wikipedia.org/wiki/Brainhttp://en.wikipedia.org/wiki/Medulla_oblongatahttp://en.wikipedia.org/wiki/Central_nervous_systemhttp://en.wikipedia.org/wiki/Occipital_bonehttp://en.wikipedia.org/wiki/Lumbar_vertebraehttp://en.wikipedia.org/wiki/Vertebral_columnhttp://en.wikipedia.org/wiki/Spine_(anatomy)http://en.wikipedia.org/wiki/Spine_(anatomy)http://en.wikipedia.org/wiki/Brainhttp://en.wikipedia.org/wiki/Neural_circuithttp://en.wikipedia.org/wiki/Neural_circuithttp://en.wikipedia.org/wiki/Reflexhttp://en.wikipedia.org/wiki/Central_pattern_generator


spinal cord has three major functions: as a conduit for motor information, which travels down the

spinal cord, as a conduit for sensory information in the reverse direction, and finally as a center

for coordinating certain reflexes.

4. Draw the diagram & equivalent circuit of a differential capacitance pressure transducer & briefly

explain its operation. (NOV 2007)

5. Discuss the different ways of transport of ions through the cell membrane. (NOV 2011)

Same as Q1

6. Explain the different parts of central nervous system & their activity. (NOV 2011)

Same as Q2

7. Briefly explain the action of piezoelectric transducer as arterial pressure sensor. (NOV 2011)


8. Explain the working of fiber optic temperature sensor. (NOV 2011)


9. Explain the structure of human cell & its constituents with neat diagram. (MAY 2012)

CELL & ITS STRUCTURE:

The basic living unit of the body is the cell. Each organ of our body is an aggregate of many

different types of cells held together by intercellular supporting structures. Each type of cell

performs one type of function. The entire body contains 100 trillion cells. Among these 25

trillion cells are red blood cells which transport oxygen from lungs to tissue. Generally all cells

have the ability to reproduce new cells whenever the cells of a particular type are destroyed.

Further in all cells oxygen combines with carbohydrate, fat & protein to release the energy

required for the cell function.

Each cell consists of a centrally located nucleus (cell core) surrounded by the cytoplasm(cell

body). The nucleus is separated from the cytoplasm by a nuclear membrane and the cytoplasm

is separated from the surrounding fluids by a cell membrane. The different substance which

make up a cell are collectively is called protoplasm which is composed of water electrolytes,

proteins, lipids and carbohydrates.

Water is the principal fluid medium of the cell & its concentration is in between 70& 85%. Water

serves as solvent for various chemicals to produce chemical reactions. The electrolytes present

in the cell are potassium, magnesium, phosphate, sulphate, bicarbonate & small quantities of

sodium, calcium and chloride. The electrolytes provide inorganic chemicals for cellular reactions.

Further electrolytes at the cell membrane allow transmission of electrochemical impulses in

nerve & muscle fibers and the intracellular electrolytes determine the activity of different

enzymatically catalyzed reactions that are necessary for cellular metabolism. Proteins

constitutes 10 – 20% of the cell mass & are divided into structural proteins & globular

proteins(enzymes). Structural proteins are in the form of long thin filaments which are


composed of polymers of many protein molecules. They are used to provide the contractile

mechanisms of all muscles. The globular proteins are globular form & are mainly the enzymes

which catalyze the chemical reactions which provide energy for cellular reactions. Lipids are

composed of different types of materials. They are fat soluble & water soluble. Important lipids

are phospholipids & cholesterol which are used to form membranous barriers that separate the

different cellular compartments. Carbohydrates play a major role in nutrition of the cell. They

are stored in the cells in the form of glycogen which are used to supply the cells energy. they

are present in the extracellular fluid in the form of glucose.

The cell also contains highly organized physical structures, called organells consisting of cell’s

chemical constituents. The cytoplasm is filled with cytosol ( clear fluid portion of the cytoplasm),

in which the minute & large particles and organelle are dispersed. Ribosome are minute

granular particles in the cytosol & are composed of a mixture of Ribonucleic acid (RNA) &

proteins & they function in the synthesis of protein in the cells. Lysosomes are vesicular

organells & provide an intracellular digestive system that allows the cell to digest & therby

remove unwanted substance & damage or the forign structures such as bacteria. The

mitochondria organells are called as power house of the cell. The cells extract significant

amount of energy from the nutrients & oxygen by means of the mitochondria. The mitochondria

contains the deoxyribonucleic acid(DNA) similar to that found in the nucleus. DNA is the basic

structure of the nucleus that controls the replication of the cell. Nucleus contains large quantity

of DNA which are called genes.

The genes first reproduce themselves & after this, the cell splits by a special process called

mitosisi to form two daughter cells. Inside the nucleus there is nucleolus which contains a large

amount of RNA & protein of the type found in ribosome. The size of the cell is in the range of 5 –

10 µm.

Nature of Cancer Cells:

Generally cancer is caused by mutation or abnormal activation of cellular genes that control cell

growth 7cell mitosis. The abnormal genes are called oncogenes. The problem of mutation can

be increased by following factors.

Exposure of ionizing radiations – x rays , gamma rays & UV rays can produce ions in tissue

cells. These ions are highly reactive & can rupture DNA strands thus causing mutation.

Chemical Substance – like aniline dye derivatives from chemical plants cause mutations.

These chemical substances are called carcinogen. Carcinogens are present in cigarette

smoke.

Physical Irritants – continuous abrasion of linings of intestinal tract by some type of food

produces damage to the tissues which lead to rapid replacement of the cells by mitosis

which causes mutation.


Hereditary – Most cancer requires not only one mutation but two or three mutation before

cancer occurs.

Viruses – certain types of cancer are caused by viruses example, leukemia.

10. What are the characteristic features to be considered while selecting a transducer? (MAY 2012)


11. Mention the names of the different subsystems in our body. Explain them with respect to their

function & constituents. (MAY 2012)


12. Explain the characteristics of resting potential, with reference to

Nernst Equation. (MAY 2012)

13. Draw the block diagram of a biomedical instrument system & briefly explain its components.

(NOV 2012)


14. Discuss the specification of a medical instrument system. (NOV 2012)

Same as Q13

15. List the advantages of optical fiber sensor. (NOV 2012)

Same as Q8

16. Explain a piezoelectric ultrasonic transducer with a neat schematic diagram. (NOV 2012)

Same as Q7

17. List the cell components & their functions. (MAY 2013)

Same as Q9

18. What are the difficulties in measuring living system? Explain in detail. (MAY 2013)

MAHALAKSHMImahalakshmiengineeringcollege.com/pdf/eee/VIIsem/EI2311/UNIT 1.pdf · EI2311- BIOMEDICAL INSTRUMENTATION IV YR/ VII SEM EEE MAHALAKSHMI ENGINEERING COLLEGE TIRUCHIRAPALLI-

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