It’s What’s Inside That Counts Flashcards
212BC microscope
Greek mathmatician
Constructed burning lens to focus on sun rays on invading roman ships
First century AD Romans
Glass lenses
Roman philosopher
Watched gladiator matches through emerald
Burning glasses = focus sun rays and start fire, cauerise wounds in battle
Image enlargement = glass lense enlarged images magnifying glass
Lenses 800s AD
Reading stone
Glass sphere magnifying text
Invented by abbas firnas
First wearable glasses
1284
Salvino d-armate
First compound microscope
Zacharias and Hans Janssen in 1595
10x magnification when fully extended
Used light to see specimen
Galileo Galilei 1564-1642
Developed telescope
1609 - compound microscope
1625 - analogous telescope
ANthonie Leeuwenhoek
Magnifying glass to count threads in factory
Taught himself to grind and polish curved lesnes
270x magnification
Wearable on one eye
Father of microscopy anthonie leeuwenhoek use of microscope
Bacteria, yeast, red blood cells, spermatozoa
English father of microscopy 1625-1703
Robert Hooke
Improved Leeuwenhoeks microscope
Compound micrscope with quality lense
Included light source
Improved quality of speciment image
First person to describe cells
Robert hookes microscope dsecribe
Used oil lamp for light source with water reservoir
And looked similar to modern day telescope but a tube
WHat did hooke see when he looked at the cork in 1665
Cells
What did schwann and schleidden state in 1839
Cell is the unit of structure, physiology and organisation of living things
Cell retains a dual existence as a distinct entity and as a building block in the structure of organisms
Microscopes over next two centuries - focus, financial and lense issue
Focus issue:
Improved focus mechanisms
Greater control
Financial:
Investment, attracted rich and talented individuals, combinations of glass makers, physicists, biologists, chemists, menufacturers, metal workers
Lense:
Improved lense, different type of glass, more compatiable lsnses in compound microscopes
Before X-ray discvery
Used touch if smoething lodged in you and swallowed
James Garfield
President for 4 months
Assasinated
Bullet lodged in spine died from blood poisoning
Chief physician couldnt locate bullet
Alexander bell invented metal detected to find bullet but failed to locate it due to bed springs garfield was lying on
Victorian photographic revolution
Increase in photography
Helped discover xrays
Sir william crooke
Investigate cathode rays using vacuum
High voltage in tubes caused e- to pass from one end to the other
Glow made e- released and hit end f tube
Image of cross occurs because the metal cross bloclks e-
William rontgen
Cathode rays using crooked tube
Tube leaked phosphorescent paint, began to flow
Tested what rays could pass through on painted screen
Producing xray image
How were xrays first used
Treat skin disorders
Locate foreign bodies
Produced side effects
How to make an xray
Tubes from rontgen
High energy ei pass from cathode through tube hitting metal target on anode
Releading high energy radiation
Why do xrays see through stuff
Dense objects absorb photons
Less dense pass through (soft tissue)
Parts used when detecting xrays
Photographic plate
Photostimulable phosphors
Semiconductor detectors
What is radiology
Specialised use of xrays for diagnostic imaging
Tongen sterophotogrammetry
Analyses precise position of markers within the body
Joint replacements
Xray crystallography
Allows precise locations of individual atoms to be identified from crystals
Discovered dna is a double helix and proteins
WHen must you use a crystal for xray crystallography
Pure sample with ordered structure
Sample rotated xray beam and diffraction pattern
Computers piece together information to form electron density map
Magnification definition
Enlarging an object/ specimen relative to its original size
Ratio describing the dimensions of the viewed specimen relative to its actual size of object
Resolution definition
Ability to separate and distinguish 2 individual points in a specimen viewed through a microscope
Sharpness of image
Reltes to wavelength of light source
Embedding
Fixed tissue embedded in wax or resin which will harden
Tissue no longer flimsy, makes sections or slices easier ot cut
Sectioning
Tissue blocks sectioned or sliced using microtome
Visualisation of individual cells
Frozen tissue sectioned on a cryostat
Staining
stained with organic dyes
choice of stain depends on tissue and what you want to see
MRI stands for
Nuclear Magnetic resonance imaging
Powerful magnets excite water molecules in human tissue, detected by radio frequency coil
How does MRI work
Magnets align nuclei and put them in an excited state
Mri scanner passes radio frequency waves
Radio frequency removed nuclei return back to aligned states
Viewing individual atoms can produce very thin slices and more detail than CT scan
fMRI
Identifies active nerunal activity
Identifies O2 usage
Active cells more O2 consumption
Plot info on top of MRI scan
Ultrasound
Improved outcome of pregnancies, ability to identify complications
Sound waves pass through soft tissue, easily and are reflected to differing degrees by internal structures
3D ultrasound
Provides much more detial than 2D
Not better at identifying problems
Echocardiography
Uses doopler effect to monitor movement
2D or 3D
Allows doctors to identify problems with minimal invasive techniques
Doppler ultrasound
Blood moves away from sensor, reflected sound waves longer than original wave
Moves towards = reflected sound waves shorter
Bioluminescent imaging
Florescent proteins
Transgenic mice have genes encoding proteins switched on in specific places
Sensitive cameras detect light generated by proteins = green fluorescent protein, luciferase
What is Luciferase
Enzyme found in many species of insect
Enzyme + substrate = emits very bright light
Firefly
Using Luciferase in imaging (mice)
Gene switches on in cancerous cells in mouse models
Only cancer cells will light up
Detect light through skin
This method of imaging is highly quantitative, light is directly proportional to amount of gene expression in animal tissue
ANgiography
Visualise blood vessels in real time in living tissue
Brain, heart, kidneys
Coronary angiography
Allows physicians to visualise the blood vessels of the heart
Used for coronary heart disease = narrowing of blood vessels supply heart
Stents inserted
Flurescence microscope describe
1) specimen contains fluorescent molecule, emits green light excited with blue light
2) fitler lets light of pssecific wavelength through
3) mirror reflects light below 510nm
4) filter only lets green fluorescent light through
5) eye only sees green fluorescing molecules on dark backgroun
Example of thing used in fluerescence microscope
Nerve cells contain green fluorescent molecule
Detect specific molecules inside or outside cell
Dark background increases contrast sensitivity
Name a commonly used florescent molecule
GFP
From jellyfish
How to see mitosis in fluerscent microscope
Spindles green
Condensed chromosomes blue
Centromeres red
GFP found when
Improved in 1990s
Martin chalfie, osuma shimomura, roger tsien
Live cell imaging
Allows changes in cell behaviour to be monitered in real time
GFP uses list
Gene expression
Show where cell proteins are localised
Protein activity
Protein movements tracking
Electron beam TEM
Travels in vacuum
Focused by magnetic coils
Electron beam absorbed by electron dense areas of specimen
Electron beam - SEM
Lower resolution/ magnification
As TEM but doesnt measure electrons absorbed by specimen
Instead measures electrons that bounce off specimen
3D images
