Bio medical.pdf

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Biomedical InstrumentationEI 2311

Palani Thanaraj K.Assistant ProfessorDepartment of EIE

St.Josephs College of Engg.

[email protected]

June 24, 2013

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Overview I

1 Physiological Systems

Anatomy of CellCell Structure

2 Cell PotentialsResting Potentials

Action PotentialsNeuronal Potentials

3 Biomedical EngineeringNervous SystemCardiac System

Cardio Vascular SystemInstrument Technology

4 Biomedical TransducersFibre Optics

Piezoelectricity2 / 2 2


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Overview II

Ultrasound

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Physiological Systems Anatomy of Cell

Human Cell - Facts

Cell is the building block of all living organisms.

A normal adult will have hundreds of Trillions of cells.

Cell body is predominantly made up of plasma (water).

Human Cell consist of smaller self organized structures called cellorganelles.

Cell organelles are functional elements of the cell

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Physiological Systems Cell Structure

Structure of Human Cell

Cell Organelles

Cell Membrane

A semipermeable Lipid layer.

Selectively allows ions to passthrough it.

Cytoplasm

A fluid like inner medium con-sist of mainly water and ions

It encloses the cell organelles

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S C S


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Physiological Systems Cell Structure

Structure of Human Cell-Contd.

Cell Organelles

Nucleus

Control Center of the CellContains DNA

Involves in Protein synthesisEndoplasmic Reticulum

Consist of Rough and SmoothERER with Ribosomes attached

is called Rough ERCoordinates protein synthesiswith Ribosomes

Golgi apparatus

Packaging and Transportationunit of the cell

Cytoskeleton

It consist of Microtubules andfilamentsGives a structure to the cell

Mitochondria

Energy power house of the cellBreaks ATP molecules to pro-duce energy and ADP(Byproduct)

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Cell Potentials Resting Potentials

At Resting State

No Excitation

At rest the concentration ofNa+

ions is less in the intracellular

fluid.The flow ofK+ ions in and outof the cell is equal.

The net effect is that there isslightly negative potential in-side the cell. This is termed asResting potential(70mv).

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Cell Potentials Action Potentials

External Stimulus

When a cell is excited by anexternal stimulus the propertiesof the cell membrane is changed.

Na+ channels are opened which

causes rapid movement of

Sodium ions into the cell.The addition of Sodium ionscreates a positive potential calledAction potential(+20mv).

After a time interval Sodiumpump is activated which turnsthe cell to its normal state.

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Cell Potentials Neuronal Potentials


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Cell Potentials Neuronal Potentials

Functional element of Neuron-synapse

SomaThe cell body of neuron isSomaIt has two regions: a) Dendronb) AxonOther organelles are similar toany cell

Neuronal States

At resting state (No excita-tion)

Excited state (with stimula-tion) produces action poten-tialsInhibited state(with stimula-tion) produces negative poten-tial

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Biomedical Engineering Nervous System


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Biomedical Engineering Nervous System

Nervous System

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Biomedical Engineering Cardiac System


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Biomedical Engineering Cardiac System

Cardio Vascular System

The heart can be considered astwo parallel connected pumps.

The right hand side is called the

right heart(Volume Pump)The left hand side is called theleft heart (Pressure Pump)

Impure blood from all the parts

of the body is collected by Venacava and drained in the rightatrium.

The right ventricles then trans-port the impure blood to thelungs for pulmonary ventila-

tion.(Pulmonary Circulation)Once the impure blood is oxy-genated the pure blood drainsinto the left atrium.

And then the left ventricles pumpthe pure blood to all the parts ofthe body.(Systemic Circulation)

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Biomedical Engineering Cardio Vascular System


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Biomedical Engineering Cardio Vascular System

Cardiovascular system

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Biomedical Engineering Instrument Technology


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g g gy

Biomedical Instrument

Types

It refers to broad class of electronic devices and systems. Based on thenature of signal acquisition they are broadly classified as follows:

Direct/Indirect: Based on thenature of the output. It can bedirect measurement of parameteror inferred in terms of anotherparameter.

Invasive/Non-Invasive: Based onContact Or Non contact elec-trode placement system.

Sensor/Actuator: The systemcan be a bio medical sensoror can be externally operateddevice.

Static/Dynamic: Static devices

measures temporal averageswhereas dynamic devices pro-vide real time monitoring.

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Block Diagram

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Performance Parameters

Static parametersAccuracy: Degree of closeness ofthe measured value to the truevalue.

Precision: It is the measure ofReproducibility of the parame-ters.

Resolution: The smallest quan-tity that can be measured with

certainty.Sensitivity: Sensitivity measuresthe ratio of Output to Inputvalue.

Dynamic parameters

Linearity: A system which sat-

isfies Superposition and additiverule.

Time in variance: Nature of thesystem response to input delays.

General Parameter: Systematicand Random Errors.

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Biomedical Transducers Fibre Optics


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Temperature sensor

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Biomedical Transducers Fibre Optics


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Temperature sensor-Description

Fiber optic temperature sensors are recent additions to temperaturetransducer family.

They promise higher efficiency and precision in temperature measure-ments.

There are two types namely a) Phase interference type b) fiberdeformation type.

In phase interference type the temperature measurement is madebased on change in phase difference between the incident radiationand reflected radiation due to temperature variations.

In fiber deformation type the temperature variations causes change inthe dimension of the bimetallic strip. This in turn deforms the fiberthere by changing the optical properties of the fiber.

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Biomedical Transducers Piezoelectricity


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Piezoelectric

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Biomedical Transducers Piezoelectricity


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Piezoelectricity-Description

Piezoelectric crystals have a property that when they are subjected tomechanical stress the charge density in the material changes.

The piezoelectric material can be considered as a charge generator.

The change in charge density constitute a potential difference.

The equivalent circuit of a piezoelectric crystal is illustrated withparallel resistors and capacitors.

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Biomedical Transducers Ultrasound


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Ultrasonic Transducer

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Biomedical Transducers Ultrasound


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Ultrasonic Transducer - Description

Piezoelectric crystals are used in ultrasonic transducers.

Inverse piezoelectric effect is used in which when the material issubjected to electric field mechanical vibrations are produced.

These vibrations are ultrasound waves which finds widespread applica-tions in Medical imaging.

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The End

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