Lab 10 microscopy

Why is the microscopy slide shining a blue light? a) The blue light has a longer wavelength than the green light; therefore, it excites the fluorophore b) Phalloidin is excited by blue light analogous to DAPI c) The green fluorescent dye attached to phalloidin is excited by blue light and emits green light d) The high energy blue light initiates the crosslinking of actin and phalloidin

c) The green fluorescent dye attached to phalloidin is excited by blue light and emits green light

Which of the following statements is NOT true for DAPI staining? a) DAPI is excited by UV light b) DAPI stains the cell nuclei c) The light source only emits UV light d) DAPI emits blue light

c) The light source only emits UV light

Which statement is true? a) Here we see villi, they behave like tentacles of an octopus that help to move the food towards the large intestine. b) Here we see the villi, cell extensions that increase the surface area of the small intestine. c) The surface of the small intestine is enlarged on many levels. Here we can see the villi d) Here we see the microvilli that enlarge the surface area and enable efficient nutrient uptake.

c) The surface of the small intestine is enlarged on many levels. Here we can see the villi

What is the function of the epithelium? a) Build a barrier that only allows certain substances to pass through b) Take up nutrients by passive and active transportation c) Building an impermeable barrier for food-borne pathogens d) All answers are correct

d) All answers are correct

How could we build a microscope with a higher resolution? a) Use electromagnetic waves with shorter wave lengths than visible light and use a sensor to produce a picture b) We could drag a tiny needle over the surface of our sample and record the position of the needle to record the surface structure c) Electrons have also wave-like properties; we can use magnets instead of lenses and bombard the sample with electrons instead of light d) All of these answers are good ideas for a high-resolution microscope

d) All of these answers are good ideas for a high-resolution microscope

Interact with answer the What is the aniline blue-stained structure in the sample? It is a stringy mass beneath the intestinal epithelium that extends into the villi. a) Microtubules b) Blood vessels c) smooth muscle cells d)extracellular tissue

d) Extracellular tissue

What type of epithelium is present in the small intestine? a) Simple squamous epithelium b) Pseudostratified columnar epithelium c) Stratified cuboidal epithelium d) Simple columnar epithelium

d) Simple columnar epithelium

Which statement is true? a) The coat proteins of the virus have fluorescent properties and appear red if they are excited with UV light b) Actin fibers will be green, because the dye linked to phalloidin absorbs green light c) DAPI is a blue fluorescent protein linked to an antibody that specifically binds DNA d) The filter cubes of the microscope consist of an excitation filter, dichroic mirror and emission filter

d) The filter cubes of the microscope consist of an excitation filter, dichroic mirror and emission filter

Why is it not possible to achieve a higher resolution in the light microscope? a) A higher resolution cannot be achieved because of the shape of the lenses b) The speed of light is the limiting factor c) The strength of light cannot be increased, otherwise the sample will heat upca d) The wavelength of visible light is too long

d) The wavelength of visible light is too long

What is the connective tissue and extracellular matrix composed of? a) All of these b) Proteoglycans c) Polysaccharides d) Collagen

a) All of these

Which of the statements below is correct? a) The basal side is facing towards the left side of the screen b) The apical side of the epithelium is facing towards the left c) The basal side faces towards the lumen d) The apical side is on top of the screen and the basal side on the bottom

a) The basal side is facing towards the left side of the screen

What does the light red layer between the white lumen and blue lamina propria consist of? a) Mucus b) Epithelial cells c) Brush border d) Single layer of plasma membrane

b) Epithelial cells

Why do we have to start with the lowest magnification to examine a new slide? a) If the light is too strong the high magnification might blind the observer b) It is easier to focus on the specimen c) The rotating nosepiece with the objective lenses can only be rotated in one direction d) The objectives for high magnifications are much larger, so the slide cannot be placed on the stage

b) It is easier to focus on the specimen

Make sure you only count the lymphocytes in the epithelial layer with the villi (light red) and not the ones in the lamina propria at the base of the epithelial cells (blue stain). Remember that the nuclei of the lymphocytes are slightly darker and smaller than the ones from the epithelial cells. a) Yes, there are more than 50 lymphocytes per 100 epithelial cells b) No, there are fewer than 10 lymphocytes per 100 epithelial cells c) This can not be determined without a special stain d) No, there are no lymphocytes in the epithelium at all

b) No, there are fewer than 10 lymphocytes per 100 epithelial cells

Which words fit into the gaps? Transmission electron microscopes allow us to see structures at a high [GAP]. If we want to take images with a high [GAP] we ideally use fluorescence microscopy . a) Contrast, Resolution b) Resolution, Contrast c) Brightness, Contrast d) Resolution, Brightness

b) Resolution, Contrast

What can you conclude from the distribution of the red fluorescence? a) The virus is evenly distributed all over the epithelium b) The virus seems to accumulate in certain areas c) The virus accumulates in the nuclei of certain cells d) The antibodies are very unspecific

b) The virus seems to accumulate in certain areas

Have a look at the image and figure out where the retro viruses accumulate. a) The virus infects goblet cells b) They accumulate around lymphocytes c) The virus has a high affinity to mucus d) The virus nonspecifically infects enterocytes

b) They accumulate around lymphocytes

What structure seals the space between two cells and makes it impermeable? a) Desmosomes b) Tight junctions c) Adherens junctions d) Glycocalyx

b) Tight junctions

What are the macroscopic structures, which point into the lumen (white), called? a) Microvilli b) Villi c) Crypt d) Lymphocyte

b) Villi

What are the three different cells called? a) Absorptive enterocytes, brush cells, and lymphocytes b) Absorptive enterocytes, goblet cells, and lymphocytes c) Absorptive enterocytes, brush cells, and goblet cells d) Brush cells, goblet cells, and lymphocytes

c) Absorptive enterocytes, brush cells, and goblet cells

Which of the following chemicals was NOT used to stain this tissue? a) Anilin to stain connective tissue, extracellular matrix, glycoproteins, and mucus in blue b) Fuchsin to stain nuclei in dark red c) Eosin to stain eosinophilic structures in various shades of red, pink, and orange d) Orange G to stain proteins in light red

c) Eosin to stain eosinophilic structures in various shades of red, pink, and orange

What are the oval-shaped structures that can be found all over the slide? a) Viruses b) Erythrocytes c) Nuclei d) Ribosomes

c) Nuclei