Characteristics of Sensors:
Selecting a Sensor Based on its Traits
Sensors are used by engineers to characterize the characteristics or behavior of an object or system. Choosing the right sensor for the job is critical.
A sensor takes an input quantity and converts it to an output quantity. Sensors may be simple physical measurement systems, or complex electronic devices requiring sophisticated data acquisition systems. No matter the type of sensor, input type, or output type, every sensor has inherent characteristics that allow the user to select the right sensor for the task at hand.
Sensor Characteristics
Some sensor characteristics include:
· Input Range
· Output Range
· Accuracy
· Repeatability
· Resolution
Input Range:
Input range is the maximum measureable range that the sensor can accurately measure. For example, a compression load cell may have an input range of 0 - 5000 pounds. The load cell cannot accurately measure "negative", or tensile loads, or compressive loads greater than 5000 pounds. Generally, quantities outside of the input range can be measured, but characteristics such as accuracy and repeatability may be compromised when the input is outside of the specified range.
Output Range:
Output range generally refers to electronic sensors, and is the range of electrical output signal that the sensor returns. However, the output range could be a physical displacement, such as in a spring scale, or rotation, such as in a clock-style analog thermometer. The output range is related to the input range by the conversion algorithm specific to the sensor type, and the algorithm may include factors based on the calibration of the specific sensor.
Accuracy
Accuracy actually refers to the amount of error, or inaccuracy, that may be present in a sensor. Accuracy can be stated as a unit of measurement, such as +/- 5 pounds, or as a percentage, such as 95%. In most cases, increased accuracy results in an increased cost for a sensor.
Repeatability
Repeatability, as the name implies, refers to how often a sensor under the same input conditions will return the same value. If a sensor is designed to be used over and over again, it is important that the output value is accurate over every measurement cycle for the life of the sensor. Repeatability is determined by calibration testing of the sensor using known inputs.
Resolution:
Resolution is the smallest unit of measurement that the sensor can accurately measure. Some transducers return output signals in discrete steps, and therefore the resolution is easily defined. Resolution can be stated as a unit of measurement or as a percentage. For electronic sensors, resolution is also dictated by the resolution of the signal conditioning hardware or software.These qualities are common to all sensors, no matter what characteristic is being measured. All of these traits must be considered when selecting the right sensor for the specific needs of a test.
Tuesday, March 31, 2009
INTRODUCTION TO OPTICAL SENSOR
Using Light as a Measurement Tool
Optical sensors detect the presence or behavior of light waves. This could include light in the visible spectrum, or outside the visible spectrum.
Optical sensors are a class of sensors that use light waves as an input. These light waves can be used directly to determine the proximity of an object, or indirectly to measure other properties. There are several different types of optical sensors:
· Photodetectors – Photodetectors, also known as proximity sensors, are used to determine if a moving object enters the range of a sensor. The most commonly found photodetector is the “electric eye”. This type of sensor works by projecting a beam of light from a transmitter to a receiver across a specific distance. As long as the beam of light maintains a connection with the receiver, the circuit remains closed. If an object passes through the beam of light, the continuity of the circuit is lost, and the circuit opens. An example of this type of sensor is a garage door opener safety sensor that will halt the closing of the door if an object breaks the beam.
· Infrared sensors – Active infrared sensors project a beam of light in the infrared spectrum and receive the returning reflection from objects in the sensor’s range. Infrared sensors can be used as proximity sensors, such as in automatic doors. Passive infrared sensors are used to measure the radiation of heat within its range. Examples of passive infrared sensors include “heat-seeking” missile guidance systems and infrared thermography systems.
· Fiberoptic sensors – Fiberoptic sensors can be used to measure a wide range of physical phenomena, depending on the configuration of the sensor. Optical fibers can be coated with materials that respond to changes in strain, temperature, or humidity. Optical gratings can be etched into the fiber at specific intervals to reflect specific frequencies of light. As the fiber is strained, the distances between the gratings change, allowing the physical strain to be measured.
· Interferometers – An interferometer is a device that adds waves from two light sources, generating an interference pattern. The pattern can be used to determine properties of the waves. Interferometry is used in many industries, but its most visible use is in astronomy. Two small telescopes mounted a fixed distance apart can achieve the resolution of a single telescope with a diameter equal to the distance between the two telescopes. Early interferometers were limited to large wavelength radio telescopes, but are now applied to shorter wavelengths of light. This method allows astronomers to measure the diameters of stars, and future projects using interferometers will help astronomers detect and perhaps measure extrasolar planets.
Optical sensors can in many cases provide non-contact measurement in environments where direct contact of electrical circuitry is not possible, such as in high-voltage applications. Optical sensors are used for both very low-tech and very-high tech applications.
Optical sensors detect the presence or behavior of light waves. This could include light in the visible spectrum, or outside the visible spectrum.
Optical sensors are a class of sensors that use light waves as an input. These light waves can be used directly to determine the proximity of an object, or indirectly to measure other properties. There are several different types of optical sensors:
· Photodetectors – Photodetectors, also known as proximity sensors, are used to determine if a moving object enters the range of a sensor. The most commonly found photodetector is the “electric eye”. This type of sensor works by projecting a beam of light from a transmitter to a receiver across a specific distance. As long as the beam of light maintains a connection with the receiver, the circuit remains closed. If an object passes through the beam of light, the continuity of the circuit is lost, and the circuit opens. An example of this type of sensor is a garage door opener safety sensor that will halt the closing of the door if an object breaks the beam.
· Infrared sensors – Active infrared sensors project a beam of light in the infrared spectrum and receive the returning reflection from objects in the sensor’s range. Infrared sensors can be used as proximity sensors, such as in automatic doors. Passive infrared sensors are used to measure the radiation of heat within its range. Examples of passive infrared sensors include “heat-seeking” missile guidance systems and infrared thermography systems.
· Fiberoptic sensors – Fiberoptic sensors can be used to measure a wide range of physical phenomena, depending on the configuration of the sensor. Optical fibers can be coated with materials that respond to changes in strain, temperature, or humidity. Optical gratings can be etched into the fiber at specific intervals to reflect specific frequencies of light. As the fiber is strained, the distances between the gratings change, allowing the physical strain to be measured.
· Interferometers – An interferometer is a device that adds waves from two light sources, generating an interference pattern. The pattern can be used to determine properties of the waves. Interferometry is used in many industries, but its most visible use is in astronomy. Two small telescopes mounted a fixed distance apart can achieve the resolution of a single telescope with a diameter equal to the distance between the two telescopes. Early interferometers were limited to large wavelength radio telescopes, but are now applied to shorter wavelengths of light. This method allows astronomers to measure the diameters of stars, and future projects using interferometers will help astronomers detect and perhaps measure extrasolar planets.
Optical sensors can in many cases provide non-contact measurement in environments where direct contact of electrical circuitry is not possible, such as in high-voltage applications. Optical sensors are used for both very low-tech and very-high tech applications.
INTRODUCTION TO SENSORS
How Engineers Use Sensors to Measure Object Properties and Behaviors:
Electrical and mechanical sensors are widely used to characterize the performance and properties of components and systems, but are also found in household objects.
Sensors are electrical or mechanical components that are used to measure a property or behavior of an object or system. Some sensors measure properties directly, other sensors measure properties indirectly, using conversions or calculations to determine results. Sensors are used by scientists and engineers during research and testing activities, but they can also be found in many household objects, such as temperature sensors in an oven to accelerometers in an automobile airbag system. Sensors are generally categorized by the type of phenomenon that they measure, rather than the functionality of the sensor itself.
MECHANICAL SENSORS:
Mechanical sensors measure a property through mechanical means, although the measurement itself may be collected electronically. An example of a mechanical sensor is a strain gauge. The strain gauge measures the physical deformation of a component by experiencing the same strain as the component, yet the change in resistance of the strain gauge is measured electrically. Other types of mechanical sensors include:
· Pressure sensors
· Accelerometers
· Potentiometers
· Gas and fluid flow meters
· Humidity sensors
ELECTRICAL SENSORS:
Electrical sensors measure electric and magnetic properties. An example of an electrical sensor is an ohmmeter, which is used to measure electrical resistance between two points in a circuit. An ohmmeter sends a fixed voltage through one probe, and measures the returning voltage through a second probe. The drop in voltage is proportional to the resistance, as dictated by Ohm's Law. Other electrical sensors include:
· Voltmeter/Ammeter
· Metal detector
· RADAR
· Magnetometer
THERMAL SENSOR:
Although all thermal sensors measure changes in temperature, there are a variety of types of thermal sensors, each with specific uses, temperature ranges, and accuracies. Some types of thermal sensors include:
· Thermometers
· Thermocouples
· Thermistors
· Bi-metal thermometers
CHEMICAL SENSORS:
Chemical sensors generally detect the concentration of a substance in the air or in a liquid. Some chemical sensors, such as pH glass electrodes are designed to be sensitive to a certain ion. Some other types of chemical sensors include:
· Oxygen sensors
· Carbon monoxide detectors
· Redox electrodes
OPTICAL SENSOR:
Optical sensors detect the presence of light waves. This could include light in the visible spectrum, or outside the visible spectrum, in the case of infrared sensors. Some types of optical sensors include:
· Photodetectors
· Infrared sensors
· Fiberoptic sensors
· Interferometers
OTHER TYPE OF SENSOR:
There are many other types of sensors that don't fall into one of the broad categories described here. Some of these sensors include:
· Radiation sensors, including Geiger counters and dosimeters
· Motion sensors, including radar guns and speedometers
· Acoustic, including sonar and seismometers
· Gyroscopes
While sensors are used frequently by engineers and scientists in their studies, sensors are also use in many household products. Sensors can be found in many everyday objects, including touch-sensitive buttons and screens, infrared remote controls, motion-sensitive lighting, and home thermostats.
Proximity Sensors:
Proximity sensors may be of the contact or non-contact type. Contact proximity sensors are the least expensive. Proximity sensors can have one of many technology types. These include capacitive, eddy current, inductive, photoelectric, ultrasonic, and Hall effect. Capacitive proximity sensors utilize the face or surface of the sensor as one plate of a capacitor, and the surface of a conductive or dielectric target object as the other. The capacitance varies inversely with the distance between capacitor plates in this arrangement, and a certain value can be set to trigger target detection. In an eddy current proximity sensor electrical currents are generated in a conductive material by an induced magnetic field. Interruptions in the flow of the electric currents (eddy currents), which are caused by imperfections or changes in a material's conductive properties, will cause changes in the induced magnetic field. These changes, when detected, indicate the presence of change in the test object. Magnetic inductive devices are identical in configuration to the variable reluctance type and generate the same type of signal. However, inductive pickoff coils have no internal permanent magnet and rely on external magnetic field fluctuations, such as a rotating permanent magnet, in order to generate signal pulse. Photoelectric devices are used to detect various materials at long range, using a beam of light. They detect either the presence or absence of light and use this information to read the data from the output transistor. An ultrasonic proximity sensor emits an ultrasonic pulse, which is reflected by surface and returned to sensor. Speed can be determined by measuring frequency difference (Doppler Effect). The basic "Hall Effect" sensing element is a semiconductor device which, when electrical current is sent through it, will generate an electrical voltage proportional to the magnitude of a magnetic field flowing perpendicular to the surface of the semiconductor.
The most important parameter to consider when specifying proximity sensors is the operating distance. This is the rated operating distance is the distance at which switching takes place. Common body styles for proximity sensors are barrel, limit switch, rectangular, slot style, and ring. Important dimensions to consider when specifying proximity sensors include barrel diameter, length, width, and height.
Proximity sensors can be a sensor element or chip, a sensor or transducer, an instrument or meter, a gauge or indicator, a recorder or totalizer, and a controller. A sensor element or chip denotes a "raw" device such as a strain gage, or one with no integral signal conditioning or packaging. A sensor or transducer is a more complex device with packaging and/or signal conditioning that is powered and provides an output such a dc voltage, a 4-20mA current loop, etc. An instrument or meter is a self-contained unit that provides an output such as a display locally at or near the device. Typically also includes signal processing and/or conditioning. A gauge or indicator is a device that has a (usually analog) display and no electronic output such as a tension gage. A recorder or totalizer is an instrument that records, totalizes, or tracks force measurement over time. Includes simple datalogging capability or advanced features such as mathematical functions, graphing, etc.
Electrical and mechanical sensors are widely used to characterize the performance and properties of components and systems, but are also found in household objects.
Sensors are electrical or mechanical components that are used to measure a property or behavior of an object or system. Some sensors measure properties directly, other sensors measure properties indirectly, using conversions or calculations to determine results. Sensors are used by scientists and engineers during research and testing activities, but they can also be found in many household objects, such as temperature sensors in an oven to accelerometers in an automobile airbag system. Sensors are generally categorized by the type of phenomenon that they measure, rather than the functionality of the sensor itself.
MECHANICAL SENSORS:
Mechanical sensors measure a property through mechanical means, although the measurement itself may be collected electronically. An example of a mechanical sensor is a strain gauge. The strain gauge measures the physical deformation of a component by experiencing the same strain as the component, yet the change in resistance of the strain gauge is measured electrically. Other types of mechanical sensors include:
· Pressure sensors
· Accelerometers
· Potentiometers
· Gas and fluid flow meters
· Humidity sensors
ELECTRICAL SENSORS:
Electrical sensors measure electric and magnetic properties. An example of an electrical sensor is an ohmmeter, which is used to measure electrical resistance between two points in a circuit. An ohmmeter sends a fixed voltage through one probe, and measures the returning voltage through a second probe. The drop in voltage is proportional to the resistance, as dictated by Ohm's Law. Other electrical sensors include:
· Voltmeter/Ammeter
· Metal detector
· RADAR
· Magnetometer
THERMAL SENSOR:
Although all thermal sensors measure changes in temperature, there are a variety of types of thermal sensors, each with specific uses, temperature ranges, and accuracies. Some types of thermal sensors include:
· Thermometers
· Thermocouples
· Thermistors
· Bi-metal thermometers
CHEMICAL SENSORS:
Chemical sensors generally detect the concentration of a substance in the air or in a liquid. Some chemical sensors, such as pH glass electrodes are designed to be sensitive to a certain ion. Some other types of chemical sensors include:
· Oxygen sensors
· Carbon monoxide detectors
· Redox electrodes
OPTICAL SENSOR:
Optical sensors detect the presence of light waves. This could include light in the visible spectrum, or outside the visible spectrum, in the case of infrared sensors. Some types of optical sensors include:
· Photodetectors
· Infrared sensors
· Fiberoptic sensors
· Interferometers
OTHER TYPE OF SENSOR:
There are many other types of sensors that don't fall into one of the broad categories described here. Some of these sensors include:
· Radiation sensors, including Geiger counters and dosimeters
· Motion sensors, including radar guns and speedometers
· Acoustic, including sonar and seismometers
· Gyroscopes
While sensors are used frequently by engineers and scientists in their studies, sensors are also use in many household products. Sensors can be found in many everyday objects, including touch-sensitive buttons and screens, infrared remote controls, motion-sensitive lighting, and home thermostats.
Proximity Sensors:
Proximity sensors may be of the contact or non-contact type. Contact proximity sensors are the least expensive. Proximity sensors can have one of many technology types. These include capacitive, eddy current, inductive, photoelectric, ultrasonic, and Hall effect. Capacitive proximity sensors utilize the face or surface of the sensor as one plate of a capacitor, and the surface of a conductive or dielectric target object as the other. The capacitance varies inversely with the distance between capacitor plates in this arrangement, and a certain value can be set to trigger target detection. In an eddy current proximity sensor electrical currents are generated in a conductive material by an induced magnetic field. Interruptions in the flow of the electric currents (eddy currents), which are caused by imperfections or changes in a material's conductive properties, will cause changes in the induced magnetic field. These changes, when detected, indicate the presence of change in the test object. Magnetic inductive devices are identical in configuration to the variable reluctance type and generate the same type of signal. However, inductive pickoff coils have no internal permanent magnet and rely on external magnetic field fluctuations, such as a rotating permanent magnet, in order to generate signal pulse. Photoelectric devices are used to detect various materials at long range, using a beam of light. They detect either the presence or absence of light and use this information to read the data from the output transistor. An ultrasonic proximity sensor emits an ultrasonic pulse, which is reflected by surface and returned to sensor. Speed can be determined by measuring frequency difference (Doppler Effect). The basic "Hall Effect" sensing element is a semiconductor device which, when electrical current is sent through it, will generate an electrical voltage proportional to the magnitude of a magnetic field flowing perpendicular to the surface of the semiconductor.
The most important parameter to consider when specifying proximity sensors is the operating distance. This is the rated operating distance is the distance at which switching takes place. Common body styles for proximity sensors are barrel, limit switch, rectangular, slot style, and ring. Important dimensions to consider when specifying proximity sensors include barrel diameter, length, width, and height.
Proximity sensors can be a sensor element or chip, a sensor or transducer, an instrument or meter, a gauge or indicator, a recorder or totalizer, and a controller. A sensor element or chip denotes a "raw" device such as a strain gage, or one with no integral signal conditioning or packaging. A sensor or transducer is a more complex device with packaging and/or signal conditioning that is powered and provides an output such a dc voltage, a 4-20mA current loop, etc. An instrument or meter is a self-contained unit that provides an output such as a display locally at or near the device. Typically also includes signal processing and/or conditioning. A gauge or indicator is a device that has a (usually analog) display and no electronic output such as a tension gage. A recorder or totalizer is an instrument that records, totalizes, or tracks force measurement over time. Includes simple datalogging capability or advanced features such as mathematical functions, graphing, etc.
AUTOMATIC DIGITAL DISPLAY BLOOD PRESSURE MONITOR DEVICE WITH PRINTER:
Keep accurate records of your blood pressure readings with the Blood Pressure Monitor and Print Out. Simply wrap the cuff around your arm and press START. In seconds, your blood pressure and pulse are displayed on the large digital panel. You can then print your readings in numerical .ELECTRONICS PROVIDE FACILTIES IN MEDICAL FIELD
UNIVERSITIES IN PAKISTAN OFFER BIOMEDICAL ENGINEERING
UNIVERSITIES IN PAKISTAN OFFER BIOMEDICAL ENGINEERING:
1)SIR SYED UNIVERSITY OF ENGINEERING AND TECHNOLOGY KARACHI ,PAKISTAN.
Biomedical Engineering Department at SSUET offers degree:
BS in BioMedical Engineering
UNIVERSITY RECOGNIZED BY:
*PEC CERTIFICATION
*SINDH ASSEMBLY CHARTER
*HEC RECOGNITION
*ACU MEMBERSHIP
*H1 VISA
*CHARTER INSPECTION AND EVALUATION COMETTEE
*ISO 9001 AND 2000 CERTIFIED
UNIVERSITY WEB LINK: www.ssuet.edu.pk
2)NED UNIVERSITY OF ENGINEERING AND TECHNOLOGY KARACHI, PAKISTAN.
The Biomedical Engineering Department at NED offers two degrees:
a) B.E. in Medical Engineering.b) B.E. in Bioengineering.
Both require 5 years for completion. At present, 32 students in each category will be admitted giving a total of 64.
Medical Engineering program:
The Medical Engineering program has the following focus areas:
Instrumentation.. Diagnostic Methods and Software. Biomechanics, Ergonomics and Rehabilitation Engineering . Implants and Reconstructive Engineering.
Thus, Medical Engineering will include: design, manufacture, maintenance and use of instruments, prostheses, implants, etc.; design, implementation and use of diagnostic software; use of biomaterials for implanted devices; rehabilitation engineering, and other clinically oriented
areas.
Bioengineering program:
The Bioengineering program has the following focus areas:
Biomedical Signals and Systems.. Medical Imaging and Scanning. Sensors, Devices and Biomaterials.. Computational Biology and Bioinformatics
Thus, Bioengineering includes computational and mathematical modeling of biological systems (e.g., joints, heart, etc.); development of algorithms for analyzing biological signals (e.g., ECG, EEG, etc.), systems (e.g., brain) and processes (e.g., blood flow, respiration); biomechanics (e.g., analysis of posture, movement, gait, etc.); bioinformatics (analysis of genes and proteins); applications of micro-electromechanical systems (MEMS) and nanotechnology (e.g., biosensors); development of signal processing and control algorithms for artificial limbs and other implants; molecular engineering (e.g., drug design), etc.
UNIVERSITY WEB LINK: www.neduet.edu.pk
3)UNIVERSITY OF HEALTH SCIENCES LAHORE,PAKISTAN.
The MSc in Bio-Medical Engineering (BME) programme offers medical and engineering graduates, an opportunity of postgraduate education and training in the emerging discipline of bio-medical engineering.
4)MEHRAN UNIVERSITY OF ENGINEERING & TECHNOLOGY JAMSHORO,SINDH,PAKISTAN.
University offer BE in Biomedical Engineering.
UNIVERSITY WEB LINK:http://bm.muet.edu.pk
1)SIR SYED UNIVERSITY OF ENGINEERING AND TECHNOLOGY KARACHI ,PAKISTAN.
Biomedical Engineering Department at SSUET offers degree:
BS in BioMedical Engineering
UNIVERSITY RECOGNIZED BY:
*PEC CERTIFICATION
*SINDH ASSEMBLY CHARTER
*HEC RECOGNITION
*ACU MEMBERSHIP
*H1 VISA
*CHARTER INSPECTION AND EVALUATION COMETTEE
*ISO 9001 AND 2000 CERTIFIED
UNIVERSITY WEB LINK: www.ssuet.edu.pk
2)NED UNIVERSITY OF ENGINEERING AND TECHNOLOGY KARACHI, PAKISTAN.
The Biomedical Engineering Department at NED offers two degrees:
a) B.E. in Medical Engineering.b) B.E. in Bioengineering.
Both require 5 years for completion. At present, 32 students in each category will be admitted giving a total of 64.
Medical Engineering program:
The Medical Engineering program has the following focus areas:
Instrumentation.. Diagnostic Methods and Software. Biomechanics, Ergonomics and Rehabilitation Engineering . Implants and Reconstructive Engineering.
Thus, Medical Engineering will include: design, manufacture, maintenance and use of instruments, prostheses, implants, etc.; design, implementation and use of diagnostic software; use of biomaterials for implanted devices; rehabilitation engineering, and other clinically oriented
areas.
Bioengineering program:
The Bioengineering program has the following focus areas:
Biomedical Signals and Systems.. Medical Imaging and Scanning. Sensors, Devices and Biomaterials.. Computational Biology and Bioinformatics
Thus, Bioengineering includes computational and mathematical modeling of biological systems (e.g., joints, heart, etc.); development of algorithms for analyzing biological signals (e.g., ECG, EEG, etc.), systems (e.g., brain) and processes (e.g., blood flow, respiration); biomechanics (e.g., analysis of posture, movement, gait, etc.); bioinformatics (analysis of genes and proteins); applications of micro-electromechanical systems (MEMS) and nanotechnology (e.g., biosensors); development of signal processing and control algorithms for artificial limbs and other implants; molecular engineering (e.g., drug design), etc.
UNIVERSITY WEB LINK: www.neduet.edu.pk
3)UNIVERSITY OF HEALTH SCIENCES LAHORE,PAKISTAN.
The MSc in Bio-Medical Engineering (BME) programme offers medical and engineering graduates, an opportunity of postgraduate education and training in the emerging discipline of bio-medical engineering.
4)MEHRAN UNIVERSITY OF ENGINEERING & TECHNOLOGY JAMSHORO,SINDH,PAKISTAN.
University offer BE in Biomedical Engineering.
UNIVERSITY WEB LINK:http://bm.muet.edu.pk
Monday, March 30, 2009
HEART PHYSIOLOGY
Blood Pressure:
Blood pressure is the force exerted by blood against the wall of a blood vessel. It is commonly measured in a large artery with an inflatable cuff (Fig. 9-4) known as a blood pressure cuff or blood pressure apparatus, but technically called a sphygmomanometer. Both systolic and diastolic pressures are measured and reported as systolic then diastolic separated by a slash, such as 120/80. Pressure is expressed as millimeters of mercury (mm Hg), that is, the height to which the pressure can push a column of mercury in a tube. Blood pressure is a valuable diagnostic measurement that is easily obtained.
Cardiovascular System:
Blood circulates throughout the body in the cardiovascular system, which consists of the heart and the blood vessels (Fig. 9-1). This system forms a continuous circuit that delivers oxygen and nutrients to all cells and carries away waste products. Also functioning in circulation is the lymphatic system, which drains fluid and proteins from the tissues and returns them to the bloodstream.
The Heart:
The heart is located between the lungs, with its point or apex directed toward the left (Fig. 9-2). The thick muscle layer of the heart wall is the myocardium. This is lined on the inside with a thin endocardium and is covered on the outside with a thin epicardium. The heart is contained within a fibrous sac, the pericardium.Each of the upper receiving chambers of the heart is an atrium (plural, atria). Each of the lower pumping chambers is a ventricle (plural, ventricles). The chambers of the heart are divided by walls, each of which is called a septum. The interventricular septum separates the two ventricles; the interatrial septum divides the two atria. There is also a septum between the atrium and ventricle on each side.The heart pumps blood through two circuits. The right side pumps blood to the lungs to be oxygenated through the pulmonary circuit. The left side pumps to the remainder of the body through the systemic circuit.
Blood Flow Through the Heart:
The pathway of blood through the heart is shown by the arrows in Figure 9-2. The right atrium receives blood low in oxygen from all body tissues through the superior vena cava and the inferior vena cava. The blood then enters the right ventricle and is pumped to the lungs through the pulmonary artery. Blood returns from the lungs high in oxygen and enters the left atrium through the pulmonary veins. From here it enters the left ventricle and is forcefully pumped into the aorta to be distributed to all tissues.Blood is kept moving in a forward direction by one-way valves. The valve in the septum between the right atrium and ventricle is the tricuspid valve (meaning three cusps or flaps); the valve in the septum between the left atrium and ventricle is the bicuspid valve (having two cusps), usually called the mitral valve (so named because it resembles a bishop’s miter). The valves leading into the pulmonary artery and the aorta have three cusps. Each cusp is shaped like a half-moon, so these valves are described as semilunar valves. The valve at the entrance to the pulmonary artery is specifically named the pulmonic valve; the valve at the entrance to the aorta is the aortic valve.Heart sounds are produced as the heart functions. The loudest of these, the familiar lubb and dupp that can be heard through the chest wall, are produced by alternate closing of the valves. The first heart sound (S1) is heard when the valves between the chambers close. The second heart sound (S2) is produced when the valves leading into the aorta and pulmonary artery close. Any sound made as the heart functions normally is termed a functional murmur. (The word murmur used alone with regard to the heart describes an abnormal sound.)
The Heartbeat:
Each contraction of the heart, termed systole (SIS-to_-le _), is followed by a relaxation phase, diastole (di_-ASto_-le_), during which the chambers fill. Each time the heart beats, both atria contract and immediately thereafter both ventricles contract. The wave of increased pressure produced in the vessels each time the ventricles contract is the pulse. Contractions are stimulated by a built-in system that regularly transmits electrical impulses through the heart. The components of this conduction system are shown in Figure 9-3. They include the sinoatrial (SA) node, called the pacemaker because it sets the rate of the heartbeat, the atrioventricular (AV) node, the AV bundle (bundle of His), the left and right bundle branches, and Purkinje ( pur-KIN-je_) fibers. Although the heart itself generates the heartbeat, factors such as nervous system stimulation, hormones, and drugs can influence the rate and the force of heart contractions.
Each contraction of the heart, termed systole (SIS-to_-le _), is followed by a relaxation phase, diastole (di_-ASto_-le_), during which the chambers fill. Each time the heart beats, both atria contract and immediately thereafter both ventricles contract. The wave of increased pressure produced in the vessels each time the ventricles contract is the pulse. Contractions are stimulated by a built-in system that regularly transmits electrical impulses through the heart. The components of this conduction system are shown in Figure 9-3. They include the sinoatrial (SA) node, called the pacemaker because it sets the rate of the heartbeat, the atrioventricular (AV) node, the AV bundle (bundle of His), the left and right bundle branches, and Purkinje ( pur-KIN-je_) fibers. Although the heart itself generates the heartbeat, factors such as nervous system stimulation, hormones, and drugs can influence the rate and the force of heart contractions.
The Vascular System:
The vascular system consists of:
1. Arteries that carry blood away from the heart (Fig. 9-5). Arterioles are small arteries that lead into the capillaries.
2. Capillaries, the smallest vessels, through which exchanges take place between the blood and the tissues.
3. Veins that carry blood back to the heart (Fig. 9-6). The small veins that receive blood from the capillaries and drain into the veins are venules.
All arteries, except the pulmonary artery (and the umbilical artery in the fetus), carry blood high in oxygen. They are thick-walled, elastic vessels that carry blood under high pressure. All veins, except the pulmonary vein (and the umbilical vein in the fetus), carry blood low in oxygen. Veins have thinner, less elastic walls and tend to give way under pressure. Like the heart, veins have one-way valves that keep blood flowing forward.
Nervous system stimulation can cause the diameter of a vessel to increase (vasodilation) or decrease (vasoconstriction).These changes alter blood flow to the tissues and affect blood pressure.
WHAT IS BIOMEDICAL ENGINEERING?
BioMedical Engineering:
BioMedical Engineering combines Engineering expertise with medical needs for the enhancement of health care. It is a branch of Engineering in which knowledge and skills are developed and applied to design and solve problems in biology and medicine. Students choose Bio Medical Engineering to be service to people; for the excitement of working with living systems; and to apply advanced technology to the complex problems of medical care. The Bio Medical Engineer is a health care professional, a group that includes Physicians, Nurses and Technicians.
It is currently the most rapidly growing field of engineering all over the world. Almost every major engineering institution in the U.S., Europe, Australia, etc., has a program in biomedical engineering. Many excellent programs also exist in developing countries such as India and Egypt.
Specific Activities :
BioMedical Engineering combines Engineering expertise with medical needs for the enhancement of health care. It is a branch of Engineering in which knowledge and skills are developed and applied to design and solve problems in biology and medicine. Students choose Bio Medical Engineering to be service to people; for the excitement of working with living systems; and to apply advanced technology to the complex problems of medical care. The Bio Medical Engineer is a health care professional, a group that includes Physicians, Nurses and Technicians.
It is currently the most rapidly growing field of engineering all over the world. Almost every major engineering institution in the U.S., Europe, Australia, etc., has a program in biomedical engineering. Many excellent programs also exist in developing countries such as India and Egypt.
Specific Activities :
Example of work done by Bio Medical Engineer include:
Designing and constructing cardiac pace makers, defibrillators, artificial kidneys, and blood oxygenates, hearts, blood vessels, joints, arms and legs.
Designing computer systems to monitor patients during surgery or in intensive care, or to monitor healthy persons in UN usual environments, such as Astronauts in Space or under water divers at great depth.
Designing and building sensors to measure blood chemistry, such as potassium, sodium, O2, CO2 and pH.
Designing instruments and devices for therapeutic uses, such as laser system for eye surgery or a device for automated delivery of insulin.
Devoicing strategies for clinical decision making based on expert system and artificial intelligence, such as computer based systems for selecting seat cushions for paralyze patients or for, managing the care of patients with severe burns or for diagnostic diseases.
Designing clinical laboratories and other units within the hospital and health care delivery system that utilize advances technologies. Examples would be a computerized analyzer for blood samples, ambulance for use in rural areas or a cardiac catheterization laboratory.
Designing, building and investigating the medical imaging systems based on X – rays (Computer Assisted Tomography), Isotopes (Position Emission Tomography), Magnetic Fields (Magnetic Resonance Imaging), Ultrasound or newer modalities.
Constructing and implementing mathematical / computer models of physiological systems.
Designing and constructing bio – materials and determining the mechanical, transport, and biocompatibility properties of implant able artificial materials.
Implementing new diagnostic procedures, especially those requiring engineering analysis to determine parameters that are not directly accessible to measurements, such as in the lungs or heart.
Investigating the Bio – Mechanics of injury and wound healing.
Specialty Areas :
Designing and constructing cardiac pace makers, defibrillators, artificial kidneys, and blood oxygenates, hearts, blood vessels, joints, arms and legs.
Designing computer systems to monitor patients during surgery or in intensive care, or to monitor healthy persons in UN usual environments, such as Astronauts in Space or under water divers at great depth.
Designing and building sensors to measure blood chemistry, such as potassium, sodium, O2, CO2 and pH.
Designing instruments and devices for therapeutic uses, such as laser system for eye surgery or a device for automated delivery of insulin.
Devoicing strategies for clinical decision making based on expert system and artificial intelligence, such as computer based systems for selecting seat cushions for paralyze patients or for, managing the care of patients with severe burns or for diagnostic diseases.
Designing clinical laboratories and other units within the hospital and health care delivery system that utilize advances technologies. Examples would be a computerized analyzer for blood samples, ambulance for use in rural areas or a cardiac catheterization laboratory.
Designing, building and investigating the medical imaging systems based on X – rays (Computer Assisted Tomography), Isotopes (Position Emission Tomography), Magnetic Fields (Magnetic Resonance Imaging), Ultrasound or newer modalities.
Constructing and implementing mathematical / computer models of physiological systems.
Designing and constructing bio – materials and determining the mechanical, transport, and biocompatibility properties of implant able artificial materials.
Implementing new diagnostic procedures, especially those requiring engineering analysis to determine parameters that are not directly accessible to measurements, such as in the lungs or heart.
Investigating the Bio – Mechanics of injury and wound healing.
Specialty Areas :
Some of the well-established area within the field of Bio Medical Engineering is:
1. Bio – Instrumentation.
2. Bio – Mechanics.
3. Bio – Materials.
4. System Physiology.
5. Clinical Engineering.
6. Rehabilitation Engineering.
7. Genetic Engineering.
8. Bio Medical Electronics.
9. Robotics.
Bio Medical Engineers are employed in industry, in hospital, in research facilities of educational and medical institutions, in teaching and in government regulatory agencies. They often serve a co coordinating or interfacing functions, using their back ground in both the engineering and medical fields. In industry, they may create designs where an in depth understanding of living systems and of technology essential. They may be involved in performance testing of new or proposed products. Government positions often involve product testing and safety, as well as establishing safety standards for devices. In the hospital, the Bio Medical Engineer may provide advice on the selection and use of medical equipment, as well as supervising its performance testing and maintenance. They may also build customized devices for special health care or research needs. In research institutions, Bio Medical Engineer supervised laboratories and equipments, and participates in or directs research activities in collaboration with other researchers with such backgrounds as medicine, physiology and nursing.
Some Bio Medical Engineers are technical advisor for marketing department of companies. Some Bio Medical Engineers also have advanced training in other fields. E.g. Many Bio Medical Engineer may also have M.D. Degree, thereby combining and understanding of advances technology with direct patient care and clinical research.
Career Preparation :
1. Bio – Instrumentation.
2. Bio – Mechanics.
3. Bio – Materials.
4. System Physiology.
5. Clinical Engineering.
6. Rehabilitation Engineering.
7. Genetic Engineering.
8. Bio Medical Electronics.
9. Robotics.
Bio Medical Engineers are employed in industry, in hospital, in research facilities of educational and medical institutions, in teaching and in government regulatory agencies. They often serve a co coordinating or interfacing functions, using their back ground in both the engineering and medical fields. In industry, they may create designs where an in depth understanding of living systems and of technology essential. They may be involved in performance testing of new or proposed products. Government positions often involve product testing and safety, as well as establishing safety standards for devices. In the hospital, the Bio Medical Engineer may provide advice on the selection and use of medical equipment, as well as supervising its performance testing and maintenance. They may also build customized devices for special health care or research needs. In research institutions, Bio Medical Engineer supervised laboratories and equipments, and participates in or directs research activities in collaboration with other researchers with such backgrounds as medicine, physiology and nursing.
Some Bio Medical Engineers are technical advisor for marketing department of companies. Some Bio Medical Engineers also have advanced training in other fields. E.g. Many Bio Medical Engineer may also have M.D. Degree, thereby combining and understanding of advances technology with direct patient care and clinical research.
Career Preparation :
The Bio Medical Engineer should plan first and foremost to be a good engineer. Beyond this, he or she should have a working understanding of life sciences systems and terminology. Good communication skills are also important, because the Bio Medical Engineer provide a link among professionals with medical, technical and other backgrounds.
Career Opportunities :
1. Hospitals:
Diagnosis, Patient Care monitoring systems, orthopedics and artificial limb designing, EEG, EMG, ECG. X – Rays, Ultrasound Laboratories.
2. Pharmaceutical Companies:
Research, Development and production of drugs, techniques and devices.
3. Surgical Equipment Manufacturer.
4. Bio Medical / Bio Technology / Laboratory equipments suppliers.
5. Universities.
Teaching, Research etc.
6. Research in various areas:
Instrumentation, diagnostic and theraputic devices, artificial organs, medical information system.
Career Opportunities :
1. Hospitals:
Diagnosis, Patient Care monitoring systems, orthopedics and artificial limb designing, EEG, EMG, ECG. X – Rays, Ultrasound Laboratories.
2. Pharmaceutical Companies:
Research, Development and production of drugs, techniques and devices.
3. Surgical Equipment Manufacturer.
4. Bio Medical / Bio Technology / Laboratory equipments suppliers.
5. Universities.
Teaching, Research etc.
6. Research in various areas:
Instrumentation, diagnostic and theraputic devices, artificial organs, medical information system.
7.Government regulatory agencies
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