fys4250fysisk institutt - rikshospitalet....and slicky tricks to prepare you for the exam
TRANSCRIPT
What is a typical question?
For example:
1. Mention some different methods for measuring blood pressure, explain the different advantages, disadvantages and eventual risks associated with each method
2. Blood flow is another interesting parameter. Describe how it is possible to measure the blood flow both invasive and non-invasively and explain the advantages, disadvantages for each method. What would be the proper requirements for an amplifier in such a measurement system?
3. Do you know any non-invasive methods of measuring the oxygen concentration in the blood? Give a brief description of the manner of operation, sources of error and advantages/disadvantages
4. Give a short explanation of the function of the human heart. How is it possible to detect patology in the heart function without entering the body?
Image: Grimnes, Høgetveit. Biomedical Engineering Education & Advanced Bioengineering Learning: Interdisciplinary Concepts.
”A sensor is a mediator able to convert one or more measurands or physical variables into an equivalent signal variable of another type of quantity within a frame of a given unity”
Pallàs-Areny, Webster, Sensors 2001
What is a sensor?
QuickTime™ og en-dekomprimerer
kreves for å se dette bildet.
Image: Grimnes-Høgetveit. Biomedical Engineering Education & Advanced Bioengineering Learning: Interdisciplinary Concepts.
- Sensor system: ”comprises the total signal path from the measurand to the observer and includes all sensing, conditioning and real-time processing elements in the path”
- Electrode: ” An electrode is an electrochemical cell converting charge carriers from ions to electrons or vice versa. An electrode is only a half-sensor in the way that two electrodes are necessary in order to apply a current or read a potential difference in living tissue”
- Probe: A ”probe is a broader concept than a sensor. A probe is often comprising multiparameter sensors (e.g. temperature) and may be held by the operator and be equipped with switches and level adjustment facilities. Example: Ultrasound probe”
Source: Grimnes-Høgetveit. Biomedical Engineering Education & Advanced Bioengineering Learning: Interdisciplinary Concepts.
More definitions....
Pressure transducerand Wheatstone bridge
Image: Grimnes-Høgetveit. Biomedical Engineering Education & Advanced Bioengineering Learning: Interdisciplinary Concepts.
Membrane potential
Nernst equation for potassium K (Nor - Kalium):
][][
][log5.61
][
][ln 10 mV
K
K
K
K
nF
RTE
i
o
i
oK ==
across a cell membrane with active channels pumping K ions into the cell.
Figure 13 IR absorption spectra for some anaesthetic agent vapours.
Datex Ohmeda Division, Instrumentarium Corporation