Microscopes. THE DISCOVERY OF THE CELL. It was not until the mid-1600’s that scientists began to use microscopes to observe cells. In 1665, Englishman Robert Hooke used an early compound microscope to look at a slice of cork, plant material. CORK CELLS.
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It was not until the mid-1600’s that scientists began to use microscopes to observe cells.
In 1665, Englishman Robert Hooke used an early compound microscope to look at a slice of cork, plant material.
In Holland around the same time, Antonvan Leeuwenhoek used a single-lens microscope to observe pond water and other things.
He discovered that living things seemed to be everywhere, even in the water he was drinking.
electrons pass through thin slices of cell parts
Cells must be dead and in a vacuum
2D picture (flat)
TEM is used to study the internal structure of cells.
Do not have to cut cells into slices
Cells must be dead and in a vacuum
produces three-dimensional images of cells
SEM is used to study details of the surface of the specimen.
TEM is more powerful than SEM
SCANNIING ELECTRON MICROSCOPE
pea weevil egg
Scanning electron microscope image of white pine sheath mite
Of the 100 billion neurons in your brain. Purkinje (pronounced purr-kin-jee) neurons are some of the largest. Among other things, these cells are the masters of motor coordination in the cerebellar cortex. Toxic exposure such as alcohol and lithium, autoimmune diseases, genetic mutations including autism and neurodegenerative diseases, can negatively affect human Purkinje cells.
Hair Cell in the EarHere's what it looks like to see a close-up of human hair cell stereo cilia inside the ear. These detect mechanical movement in response to sound vibrations.
Blood Vessels Emerging from the Optic NerveIn this image, stained retinal blood vessels are shown to emerge from the black-colored optic disc. The optic disc is a blind spot because no light receptor cells are present in this area of the retina where the optic nerve and retinal blood vessels leave the back of the eye.
Tongue with Taste BudThis color-enhanced image depicts a taste bud on the tongue. The human tongue has about 10,000 taste buds that are involved with detecting salty, sour, bitter, sweet and savory taste perceptions. Thai people have very few -- most killed by eating spicy food.
Tooth PlaqueBrush your teeth often because this is what the surface of a tooth with a form of plaque looks like.
Blood ClotRemember that picture of the nice, uniform shapes of red blood cells you just looked at? Well, here's what it looks like when those same cells get caught up in the sticky web of a blood clot. The cell in the middle is a white blood cell.
Alveoli in the LungThis is what a color-enhanced image of the inner surface of your lung looks like. The hollow cavities are alveoli; this is where gas exchange occurs with the blood.
Villi of Small IntestineVilli in the small intestine increase the surface area of the gut, which helps in the absorption of food. Look closely and you will see some food stuck in one of the crevices.
magnifying power of ocular lens X magnifying power of the objective lens.
rotates to change
Support body tube
amount of light
Sharpens the image
Be careful of the cord when moving around the lab tables!!
3. Rotate the nosepiece to obtain the proper objective lens
Make sure the lens clicks into place!!
4. Look through the eyepiece and switch on the lamp
This is your field of view!
5. Place slide on stage, center specimen over stage
6. Locate specimen on low power using coarse adjustment
7. Carefully switch to medium or high power
8. Focus image with fine adjustment
Avoid damaging slide!
Do not use coarse adjustment with high power!
Four steps prepare the microscope for storage: