How to examine cells and tissues

Question 1

Where are epithelial cells found|?What is it called when epithelial cells are in clusters?

Answer 1

on the edge of other tissues and surround other tissues glands

Question 2

when epithelial cells are at the surface what happens?

Answer 2

POLARISED

Question 3

what hold epithelial cells together?

Answer 3

Anchoring proteins

Question 4

how do epithelial cells communicate?

Answer 4

junctions at their lateral and basal surfaces

Question 5

Epithelial cells are……

Answer 5

avascular no blood vessels going through them

Question 6

What is the limit of resolution?

Answer 6

the smallest distance by which two objects can be distinguished as two separate objects

Question 7

What is the mathematical expression for limit of resolution?

Answer 7

d = lambda / 2 x Na Where NA is numerical aperture when it gets dark and your pupils dilate to let more light in this increases numerical aperture when it gets brighter your pupils constrict decreasing numerical aperture

Question 8

What is the magnification of an electron microscope?

Answer 8

x500,000

Question 9

How does freeze fracture work?

Answer 9

tissue is frozen to -160 degrees-hit with a knife edge -fracture line passes through the plasma membrane exposing the interior

Question 10

scanning electron microscope

Answer 10

electrons are reflected back from the surface and received by a cathode ray tube

Question 11

what prevents putrefaction?

Answer 11

preservation and fixation

Question 12

requirements for light microscopy

Answer 12

need to preserve the tissue with formalin- specifically formaldehyde embed the tissue in paraffin wax so it can be sliced stain the tissue with eosin and haemotoxylin

Question 13

What occurs after fixation in paraffin wax?

Answer 13

-dehydrated in different concentrations to alcohols to remove water-immersed in dissolved paraffin wax overnight which allows the paraffin to penetrate between the tissues -tissue orientated in a mould and more wax added -allowed to cool to room temperature -gently ease out of mould

Question 14

How does confocal microscopy work?

Answer 14

-Laser excites a fluorescent molecule and the electrons in the dye are raised to a higher energy level-as the electron relaxes back to a lower energy state when the laser turns off a light with a higher wavelength is emitted -emitted light is sent through mirrors and a pinhole screen to a CMOS detector

Question 15

What needs to be kept constant in the internal envirinment?

Answer 15

[] of oxtgen co2 salt and electrolytes ph [] of nutrients and waste temperature of internal environmentvolume and pressure of fluid and cell compartments