Endoscope: Thin tube containing opical fibres
- 1 to carry light -1 to carry an image back
- Image seen on eyepiece or screen
- called Key Hole surgary, good as doctors only need to cut a tiny hole
Pules oximeters use light to check the oxygen levels in the blood
Haemoglobian carries oxygen from lungs to cells. It changes colour due oxygen content. Lots of oxygen - Red (oxyhaemoglobian) Lackign oxygen - Purply(reduced haemoglobin)
How it works
- Trasmitter emits two beams of light (red & infared). It also has a photo detector to measure light.
- These are placed either side of the finger (or ear lobe etc)
- Beams of light are passed through the finger, some of the light is then absorbed by the blood.
- It is the difference in light intensity before the light passes through the blood, and after, that is used to measure the oxygen levels in the blood