BiologyBiologyUnit C: Cycling of Matter in Unit C: Cycling of Matter in

Living SystemsLiving Systems

Chapter 1: Developments in Chapter 1: Developments in Imaging TechnologyImaging Technology

A Window to a New WorldA Window to a New World

Agenda:Agenda:- Introduction to MicroscopesIntroduction to Microscopes- Uses for MicroscopesUses for Microscopes- People involved in Scientific Discovery and People involved in Scientific Discovery and

Inventions/Improvements to Microscopes:Inventions/Improvements to Microscopes:- AristotleAristotle- Hans & Zacharias JensenHans & Zacharias Jensen- Robert HookeRobert Hooke- Antoni van LeeuwenhoekAntoni van Leeuwenhoek

- Types of MicroscopesTypes of Microscopes- Parts of the Compound Light MicroscopeParts of the Compound Light Microscope- Care and Use of the MicroscopeCare and Use of the Microscope

MicroscopesMicroscopes

What do we use What do we use Microscopes for?Microscopes for?– To see anything To see anything

that is difficult to that is difficult to see with the naked see with the naked eye (plant parts, eye (plant parts, animal parts)animal parts)

– http://en.wikipedia.org/wiki/Microscopehttp://en.wikipedia.org/wiki/Microscope

– Non-traditional Non-traditional uses:uses: Solving crimes: (hair Solving crimes: (hair

analysis, blood, other analysis, blood, other fluids)fluids)

Detecting crop diseases Detecting crop diseases and pathogensand pathogens

Detecting tiny defects in Detecting tiny defects in metal in bridges and metal in bridges and airplanesairplanes

Detection of diseases Detection of diseases like malaria and like malaria and TuberculosisTuberculosis

Use in Surgery Use in Surgery (laparoscopic)(laparoscopic)

A Brief HistoryA Brief History

So how did we come to use So how did we come to use Microscopes?Microscopes?– It began with Scientific Inquiry – Asking It began with Scientific Inquiry – Asking

questions about how things workquestions about how things work– Early GreeksEarly Greeks

Mostly philosophers – thinking out possible Mostly philosophers – thinking out possible answers to problems rather than testing ideasanswers to problems rather than testing ideas

Aristotle (384 to 322 B.C.)Aristotle (384 to 322 B.C.)::– Followed a pathway of accurate observations and record makingFollowed a pathway of accurate observations and record making– Set up a classification system based on his observationsSet up a classification system based on his observations– Reasoning and Interpretation followed the observationsReasoning and Interpretation followed the observations

A Brief HistoryA Brief History

Hans and Hans and Zacharias JanssenZacharias Janssen– Holland, ~1595Holland, ~1595– Father and son Dutch Father and son Dutch

lens makerslens makers– Invented the compound Invented the compound

microscope (2 lens microscope (2 lens system)system)

– Magnifying power ~ 20 Magnifying power ~ 20 XX

http://en.wikipedia.org/wiki/File:Zacharias.jpg

A Brief HistoryA Brief History

Robert Hooke (1635-Robert Hooke (1635-1703)1703)– Used a hand made Used a hand made

microscope with a 3-microscope with a 3-lens systemlens system

– Recorded observations Recorded observations of plants, animals, and of plants, animals, and non-living objectsnon-living objects

– Viewed cork and saw Viewed cork and saw many empty channels, many empty channels, which he called “cells” which he called “cells” because they looked because they looked like Monks’ cellslike Monks’ cells

http://en.wikipedia.org/wiki/Robert_Hooke

http://en.wikipedia.org/wiki/File:Hooke_Microscope-03000276-FIG-4.jpg

http://en.wikipedia.org/wiki/File:HookeFlea01.jpg

A Brief HistoryA Brief History Antoni van Antoni van

Leeuwenhoek (~1665)Leeuwenhoek (~1665)– Identified different Identified different

types of single celled types of single celled organisms such as organisms such as bacteria, sperm and bacteria, sperm and unicellular protozoaunicellular protozoa

– Highly skilled in Highly skilled in making small lenses, making small lenses, and was able to and was able to produce higher produce higher magnifications than magnifications than the compound the compound microscopes of the daymicroscopes of the day

http://en.wikipedia.org/wiki/File:Leeuwenhoek_Microscope.png

A Replica of van Leeuwenhoek’s Microscope

Microscopic section through 1 year old Ash tree wood

http://en.wikipedia.org/wiki/File:Leeuwenhoek_Eschenholz.jpg

MicroscopesMicroscopes

Units of Units of MeasurementMeasurementUnitUnit Equivalent Equivalent

MeasurementMeasurementUseful in ObservingUseful in Observing

Centimetre (cm)Centimetre (cm) 1/100 metre; 101/100 metre; 10-2-2 m m Visible objectsVisible objects

Millimetre (mm)Millimetre (mm) 1/10 centimetre; 101/10 centimetre; 10-3-3 mm

Large particles or cellsLarge particles or cells

Micrometre – also Micrometre – also known as the known as the MicronMicron ((µµm)m)

1/1000 millimetre; 101/1000 millimetre; 10-6-6 mm

Majority of cells and Majority of cells and their component partstheir component parts

Nanometre (nm)Nanometre (nm) 1/1000 micrometre, 1/1000 micrometre, 1010-9-9m m

Large molecules and Large molecules and most cell partsmost cell parts

Angstrom (Å)Angstrom (Å) 1/10 nanometre; 101/10 nanometre; 10--

1010mmMolecules and atomsMolecules and atoms

MicroscopesMicroscopes

Types of MicroscopesTypes of Microscopes– 4 basic types of microscopes (in two 4 basic types of microscopes (in two

categories):categories): Light Microscopes:Light Microscopes:

– Dissection microscopesDissection microscopes– Compound MicroscopesCompound Microscopes

Electron Microscopes:Electron Microscopes:– Scanning Electron MicroscopeScanning Electron Microscope– Transmission Electron MicroscopeTransmission Electron Microscope

Light MicroscopesLight Microscopes Use light focused on Use light focused on

the object to the object to illuminate itilluminate it

Dissection Dissection microscopemicroscope::– Image is 3-D, but it only Image is 3-D, but it only

has a low magnification, has a low magnification, so you cannot see so you cannot see individual cellsindividual cells

Compound Compound microscopemicroscope::– Image is 2-D, but the Image is 2-D, but the

magnification is magnification is powerful enough to see powerful enough to see individual cells (with a individual cells (with a low resolution)low resolution)

A thumb through a dissecting microscope

http://www.itg.uiuc.edu/exhibits/gallery/pages/image-26.htm

Human hair at 100x mag.

http://www.microscopeworld.com/MSWorld/microscope_images.aspx

Human hair at 400x mag.

http://www.microscopeworld.com/MSWorld/microscope_images.aspx

Electron MicroscopesElectron Microscopes Use a beam of electrons, Use a beam of electrons,

rather than light, to illuminate rather than light, to illuminate the object you are viewingthe object you are viewing

Scanning Electron Scanning Electron microscope (SEM):microscope (SEM):– High magnification and high High magnification and high

resolution, image is 3-Dresolution, image is 3-D– Objects are coated in gold Objects are coated in gold

then the electrons bounce off then the electrons bounce off the outside to give you a the outside to give you a black and white imageblack and white image

Transmission Electron Transmission Electron microscope (TEM):microscope (TEM):– Electron beams pass through Electron beams pass through

thin specimens of the object, thin specimens of the object, giving a 2-D image with high giving a 2-D image with high resolution at a high resolution at a high magnificationmagnification

http://www.arco-iris.com/George/microscopes/micro_fossil_02.jpg

http://www.itg.uiuc.edu/exhibits/gallery/pages/image-51.htm

Synapse from a rat’s visual cortex

Compound MicroscopeCompound Microscope

You will be using a You will be using a compound compound microscope for microscope for your labyour lab

You will need to You will need to know the different know the different parts of the parts of the microscope and microscope and how to use it safely how to use it safely and carefullyand carefully

http://www.yorkoptical.com.au/portals/0/StockImages/14001-049-I01.jpg

Compound MicroscopeCompound Microscope

http://www.yorkoptical.com.au/portals/0/StockImages/14001-049-I01.jpg

Ocular lens (eyepiece)

Body tube

Arm

Revolving nosepiece

Objective lenses

Stage

Stage clips

Light source

Course adjustment knob

Power switch

Base

Note: Fine adjustment knob and iris diaphragm do not appear on this diagram

Parts of the MicroscopeParts of the Microscope Eyepiece or Ocular Lens:Eyepiece or Ocular Lens:

– Has a lens that enlarges the image from the objective Has a lens that enlarges the image from the objective lens (usually 10X)lens (usually 10X)

Course Adjustment Knob:Course Adjustment Knob:– Brings the image into focus. Brings the image into focus. – Used only with the Used only with the low powerlow power objective lens objective lens

Fine Adjustment Knob:Fine Adjustment Knob:– Brings the image into focus with more detailBrings the image into focus with more detail– Used with the medium and high power objective lensesUsed with the medium and high power objective lenses

Arm:Arm:– Supports the microscopeSupports the microscope– Use to help carry the microscopeUse to help carry the microscope

Parts of the MicroscopeParts of the Microscope Revolving Nosepiece:Revolving Nosepiece:

– Rotating mount that holds many objective lensesRotating mount that holds many objective lenses Objective lenses:Objective lenses:

– Gathers light from a specimen and forms an inverted Gathers light from a specimen and forms an inverted imageimage

– Low = 4X magnificationLow = 4X magnification– Medium = 10X magnificationMedium = 10X magnification– High = 40X magnificationHigh = 40X magnification

Stage:Stage:– Supports the microscope slideSupports the microscope slide

Stage clips:Stage clips:– Holds the slide in placeHolds the slide in place

http://www.fotosearch.com/photos-images/microscope_2.html

Parts of the MicroscopeParts of the Microscope Iris Diaphragm:Iris Diaphragm:

– Controls the amount of light reaching the objectControls the amount of light reaching the object Light Source:Light Source:

– Sends light up through the object being viewedSends light up through the object being viewed– Also called “lamp” or “mirror”Also called “lamp” or “mirror”

Base:Base:– Supports the microscopeSupports the microscope– Also hold this when carrying the microscope (along with Also hold this when carrying the microscope (along with

arm)arm) Power Switch:Power Switch:

– Turns the light source on/offTurns the light source on/off– May or may not be present on all microscopesMay or may not be present on all microscopes

Care and Use (p. 5)Care and Use (p. 5) ReadRead the information the information beforebefore you start you start PracticePractice the skills you learn the skills you learn AskAsk questions if you are not sure! questions if you are not sure!

1. 1. AlwaysAlways use 2 hands to carry the microscope! use 2 hands to carry the microscope! In the upright In the upright position with one hand supporting the base, and one holding position with one hand supporting the base, and one holding the armthe arm

2. Do not touch the lens with anything2. Do not touch the lens with anything 3. Always check that the light switch is OFF 3. Always check that the light switch is OFF before you plug it before you plug it

inin 4. Always store your microscope with the stage 4. Always store your microscope with the stage loweredlowered and and

the revolving nosepiece at its the revolving nosepiece at its lowestlowest point point 5. Cover the microscope and return it to its storage place5. Cover the microscope and return it to its storage place 6. 6. YOUYOU are responsible for cleaning your equipment (including are responsible for cleaning your equipment (including

the glass slides) after use. the glass slides) after use. Use only lens paper to clean Use only lens paper to clean lenses.lenses.

7. Inform your teacher if your microscope does not work7. Inform your teacher if your microscope does not work

http://www.fotosearch.com/photos-images/microscope.html

Viewing Objects with the Viewing Objects with the Microscope (p. 5)Microscope (p. 5)

1. Check that the stage is 1. Check that the stage is at its lowest point at its lowest point and turn and turn the objective lens to the the objective lens to the lowest powerlowest power

2. Secure a prepared slide on the stage2. Secure a prepared slide on the stage 3. 3. While watching the stageWhile watching the stage raise it until the slide gets raise it until the slide gets

as close to the objective lens as it can as close to the objective lens as it can without touching itwithout touching it 4. Look in the ocular lens while you use the 4. Look in the ocular lens while you use the course focus course focus

to LOWER the stageto LOWER the stage until the object comes into view. until the object comes into view. Fine focus is used to get a sharper image. Adjust the iris Fine focus is used to get a sharper image. Adjust the iris diaphragm if necessarydiaphragm if necessary

5. Turn to the medium power lens. 5. Turn to the medium power lens. Only use the fine Only use the fine focus adjustment under medium and high powered focus adjustment under medium and high powered lenses!lenses!

6. 6. Lower the stage Lower the stage and return the objective lens to the and return the objective lens to the lowest power lowest power beforebefore removing the slide removing the slide

http://www.fotosearch.com/photos-images/microscope.html

A Look AheadA Look Ahead

Next Class:Next Class:– You will be using a microscope in pairs You will be using a microscope in pairs

in the laboratory for class.in the laboratory for class.– Bring your microscope handout, a Bring your microscope handout, a

pencil, and a ruler.pencil, and a ruler. It’s also not a bad idea to bring your C1 It’s also not a bad idea to bring your C1

booklet with the care and use instructions as booklet with the care and use instructions as well as the list of the parts of the well as the list of the parts of the microscopesmicroscopes