Module 1 - Biosignals and transducers

Question 1

Identify common biosignals

Answer 1

Blood pressure
Heart rate, ECG
Brain signals, EEG
Respiration rate
Oxygen saturation 
Temperature
Biopsies

Question 2

Recall the origin and basic physics of biopotentials

Answer 2

Cell membrane.
K+ on the inside of the cell, Na+ and Cl- on the inside.

When a stimulus disturbs a membrane, the sodium channels open. Sodium flows into the cell. If the charge is enough, more Na+ will flow into the cell. Cell then depolarizes because there is a positive net charge in the inside of the cell. Also K+ opens, repolarizing the cell

Question 3

TAB:
Draw electrical signal for neurons, skeletal muscle, and cardiac ventricles.
also give axis and time frame

Answer 3

• TIME = 1-2 ms, 2-5 ms, > 200 ms
• AXIS = 30 tot -90
• neuron = -75 tot 28 steil
• skeletal muscle = -90 tot 30 steil, en weer helemaal naar beneden
• cardiac ventricle = -90 stijl tot top, eerst langszaam en dan steil naar beneden

Question 4

What types of artefacts are there?

Answer 4

1. Physiological
2. Technical
3. Environmental

Question 5

Mention the 5 parts of a block diagram (for recognizing a biosignal) and explain

Answer 5

1. Transducer
2. Amplify
3. Filter
4. AD C conversion (analog to digital)
5. Post processing

Question 6

Main components of an Ag/AgCl electrode

DRAW TAB

Answer 6

• Electrode capsule
• Ag plate with AgCl film
• Electrolyte gel
• Tissue

Question 7

What is the Nernst potential?

Answer 7

The point when potassium moving out of the cell due to the concentration gradient equals the potassium moving back into the cell because of the electrostatic gradient