Histology: the cell and intro

Question 1

what is PAS used to stain for

Answer 1

sugars- magenta

Question 2

What does H&E stand for and what does it stain

Answer 2

Haemotoxylin and Eosin
nuclei- dark blue, cytoplasm/extracellular material- pink, empty space/watery interstitial fluid e.g. glycosaminoglycan matrix - white

Question 3

What does Van Gieson stain

Answer 3

elastic- black/brown

Question 4

What does Alcian blue stain

Answer 4

mucins- dark blue

Question 5

What does trichrome stain

Answer 5

3 difernet stains, stains difefrnet things

Question 6

Why do cell sizes differ

Answer 6

smaller cells e.g. lymphocytes have to move around the body so muct be smaller they are also less metabolically active so require less organelles - comparitavly motoor neurones stay in fixed place and more metaboillivaly active due to cell signalling

Question 7

define cuboidal

Answer 7

as tall as it is wide

Question 8

define squamos and e.g.

Answer 8

flat cells

Question 9

define columnar and e.g.

Answer 9

taller than wide

Question 10

define rounded and e.g.

Answer 10

rounded shape but not always spherical (erythrocytes)

Question 11

define polygonal and e.g.

Answer 11

cells have been squished togetehr and dont have unifrom shape

Question 12

define fusiform and e.g.

Answer 12

spindle like shape e.g. muscle fibres

Question 13

What is present at the nucleus

Answer 13

The nucelus holds the genetic informaation of the cell, it has a double membrane with pores in it, the memebrane is often continue with RER, DNA ascoisated with hostones to be called nucleosomethis then toghtly coils more and is called chromatin, nucelolus is presnt and that where ribsomes (rRNA) are produced.

Question 14

eurchromatin vs heterocharomatin

Answer 14

euchromatin is lighter and is actively transcribed DNA and heterchromatin is darker and transcriptionally inactive and sits close to nuclear memebrane. You can convert between euchromatin and heterchromatoin as a form of gene regulation

Question 15

Describe the appearnace and function of a mitochondrion

Answer 15

Mitochria contain a double membrane, smotth outer memebrane and highly folded ineer cristae, site of oxidative phosphorylation, conversion of ADP to ATP, has it’s own DNA

Question 16

What may you see when looking at cells of someone who has taken colchine or a colchine like drugs?

Answer 16

ring mitoses, (due to halt of mitosis at anaphase)

Question 17

What is 5’ cap and 3’ tail maid from?

Answer 17

5’ cap is made from methylated guanaine and tail is multiple adenine

Question 18

What causes down syndrome?

Answer 18

Trisomy 21 (three chromosme), due to non-disjunction of chromosomes during meiosis. Typically maternal but ocasionally paternal

Question 19

What are introns? exons?

Answer 19

introns contain non-coding sequences (IN the bin) and are spliced out of mRNA before leaving nucleus, exons contain coding sequences

Question 20

example of stop codons

Answer 20

UAA, UAG and UGA

Question 21

What are tight junctions?

Answer 21

also known as occluding junctions these junctions help create an impermebale barrier between adjacent epithelial cells and form bandlike connections. This forces molcules to move through the cell- this junctions are usefully in cells that active transport to prevent back diffusion. Particulalrly well developed in cells ligning the small bowel.

Question 22

What are desmosomes?

Answer 22

also known as anchoring junctions these junctions help provide mechanical strength to the epithelial cells. Desmososmes connect adjacent cells cytoskeleton togetehr and hemidesmosomes connect epitheilail cells to extracellular basement memebrane. These are most commonly found in adjacent columnar and cuboidal cells where they link to an ‘adhesion belt’. Also particularly well developed in squamos epithelial cells of skin

Question 23

What are gap junctions?

Answer 23

also known as communicating junctions, they allow ajacent cell-cell comunications by diffusion of molceules. They are musch more common during embryogenesis when they allow communication for spatial organisation of cells. Also important in cardiac and muscle cells.

Answer 24

microvilli contain actin filaments to help keep shape of microvilli, help incraese SA so are typically a specialisation on absorption of secretory columnar or cuboidal epithelial cells.

Question 25

where may i find a motile cilia?
what proteins are present in cilia?

Answer 25

in fallopian tubes push ova, in respiratory tract wafting mucus, in ventriles of brain

contain dynein and tubular in a 9 an 2 structure

Question 26

what is the glycolax

Answer 26

layer of protein, glycoprotein and sugar residue- appears a fuzzy like magenta coating when stained with PAS