week 2: lab 1 (microscopes)

Question 1

what microscope is used in class?

Answer 1

-light compound microscope

Question 2

name all 4 objective lens:

Answer 2

-scanning objective 4x
-medium power objective 10x
-high (power) dry objective 40x
-oil immersion objective 100x

Question 3

what is the function of the “ocular/eyepiece”?

Answer 3

-magnifies the image to be seen by human eyes
-correctly positioned when you see a single circle of light

Question 4

what is the function of the “body”?

Answer 4

-contains mirrors that bend light into oculars
- causes image to be reversed (right to left) and inverted (top to bottom)

Question 5

what is the function of the “nosepiece”?

Answer 5

-objectives are attached to the nosepiece therefore rotation of the nosepiece will move the objective lens over to the stage

Question 6

what is the function of “objectives”?

Answer 6

-contains lenses that magnify the image
-4x, 10x,40x (or 45x), and 100x

Question 7

what is the function of the “arm”?

Answer 7

-supports nosepiece
-hold on/off toggle & focus adjustment knobs

Question 8

what are the functions of the “stage/mechanical stage”?

Answer 8

-the stage is the black platform on which slide rest
-mechanical stage (silver apparatus) that holds and moves the slide to position on the stage

Question 9

what is the function of the “stage adjustment knobs”?

Answer 9

• they move the mechanical stage (silver apparatus) from left to right and top to bottom

Question 10

what is the function of the “light intensity control”?

Answer 10

• increases/decreases light output

Question 11

what is the function of the “substage condenser”?

Answer 11

-to focus the light onto the specimen, improves image sharpness

Question 12

what is the function of the “aperture diaphragm control”?

Answer 12

-controls the amount of light entering substage condenser from the light source

Question 13

what is the function of the “field diaphragm lever”

Answer 13

-opens and closes to increase/decrease light from the light source
- should remain open

Question 14

what is the function of the “ light source”?

Answer 14

-illuminator; bulb that produces light

Question 15

what is the function of the “base”?

Answer 15

-holds the illuminator and supports the rest of the microscope

Question 16

what is the function of the “fine focus adjustment knob”?

Answer 16

-rotation of the knob brings the image into sharp focus

Question 17

what is the function of the “coarse focus adjustment knob”?

Answer 17

-this knob moves the stage up and down

Question 18

what is objective maginification?

Answer 18

-magnification of the objective lens
-example: 4x (scanning) or 100x (oil immersion)

Question 19

what is total magnification?

Answer 19

-(objective lens magnification) x (ocular lens magnification) = total magnification
-example 4x (scanning) x 10x= 40x total magnification

Question 20

what is “resolution”?

Answer 20

-shows objects that are close together as separate objects

Question 21

what is “magnification”?

Answer 21

making an object appear larger with the use of both ocular and objective lens magnification

Question 22

what is “parfocal lens”?

Answer 22

-parfocal lenses maintain focus when moving from one objective to another
-will only require minor adjustments (fine adjustment)

Question 23

what is “field of view”?

Answer 23

-what you can see through the ocular lenses

Question 24

what is “working distance”?

Answer 24

-distance from the objective to the stage

Question 25

why do we use oil immersion?

Answer 25

-Oil immersion bends light differently -Allows more light to focus through the specimen (due to its refractive index) -ONLY USED in 100x objective lens

Question 26

what are dissecting microscopes used for?

Answer 26

- used to see larger objects, external structures such as a bee

Question 27

what are electron microscopes used for?

Answer 27

- Creates an image by either passing electrons through the specimen or reflecting electrons off the specimen - Transmission Electron Microscope - Scanning Electron Microscope

Question 28

what are compound light microscopes used for?

Answer 28

- use visible light and a series of lenses to create an image used for seeing living or dead cells too small to be seen with the naked eye - Bright-Field - Dark-Field - Phase-Contrast

Question 29

what are UV radiation microscopes used for?

Answer 29

- Fluorescence: uses UV radiation to interact with stains, which will fluoresce or glow when activated - Confocal: uses a laser to pass concentrated UV through thick structures such as tissues