Tissues of the body L1.2

Question 1

Relative sizes of human cells

Answer 1

Question 2

Limit of resolution

Answer 2

Min distance 2 objects can be distinguished as two seperate entities

Question 3

Light microscopy vs TEM vs SEM

Answer 3

SEM - 3D SPECIMEN
light is source, electron is source

Question 4

State the relationship between resolution and wavelength

Answer 4

Resolution is inversely proportional to wavelength

Question 5

Why is the practical limit of resolution different to the theoretic limit of resolution ?

Answer 5

Imperfections in lens
Therefore, practical lower than theoretical

Question 6

Limit of resolution: LM vs EM

Answer 6

Question 7

Conversion between micrometres and nanometres

Answer 7

1 micrometer = 10000 nanometers

1μm = 1000 nm

Question 8

Histology of intestinal epithelium

Answer 8

ELECTRON MICROSCOPE FOR SECOND IMAGE - BLACK + WHITE, uses electrons to form image not visible light

Question 9

What are benign samples?

Answer 9

Normal

Question 10

What are malignant samples?

Answer 10

Cancerous

Question 11

What are Malignancies?

Answer 11

Key characteristic histological changes

Question 12

Clinical case scenario: You have a patient with an unusual looking mole. The differential diagnosis includes
1. An atypical benign mole
2. A seborrheic wart
3. Malignant melanoma

What would you do in this situation ?

Answer 12

We cannot tell immediately what the diagnosis is

Can tell from looking at it

If not, biopsy required

Here, I have put histology, you do not need to know at the moment, but very good for context.

Question 13

What is Breslow thickness?

Answer 13

Measure of depth of melanoma invasion fron granular later of epidermis

The more the worse

Question 14

State the use of periodic acid schiff (PAS)

Answer 14

Stain - stains carbs + glycoproteins megenta

Question 15

Describe the process of performing histology

Answer 15

(From Biopsy to Microscopy):

1. Collection (collection of tissue sample, this is biopsy)
2. Fixation (chemical preservation of tissue)
3. Embedding + Processing (dehydration + solidification of tissue)
4. Sectioning (cutting solidified tissue)
5. Staining (colouring the tissue section)
6. Viewing / Analysis - microscopic viewing of stained tissue

Question 16

Define biopsy

Answer 16

Removal of tissue for microscopic examination

Question 17

State examples of biopsy procedures

Answer 17

1. Smear (cervix, buccal cavity)
2. Currertage (endometrial lining of uterus)
3. Direct incision (skin, mouth, larynx)
4. Needle, brain, liver, kidney, muscle
5. Endoscopic, lung, intestine, bladder
6. Transvascular - heart, liver

Question 18

What are artefacts?

Answer 18

Formed during tissue processing.
Can be:

1. Tearing of section due to nick in microtome knife egde
2. Air bubbles formed during tissue mounting proceadure

Question 19

Describe the role of haematoxylin (H&E STAINING)

Answer 19

A basic dye
Stains acidic components of cells purple / blue colour
(e.g. nucleolus (because it contains rRNA), chromatin (because it contains DNA)
(both of these components are basophilic)

Question 20

Describe the role of eosin ((H&E STAINING))

Answer 20

Acidic dye
Stains basic components cells shades of PINK (cytoplasmic proteins, extracellularr proteins eg collgen)
(these components are eosinophilic)

Question 21

Histology of Gastric Pit of Stomach with H&E Staining

Answer 21

Question 22

What is heterochromatin?

Answer 22

Tightly packed DNA

Question 23

What is euchromatin?

Answer 23

Unravelled DNA

Question 24

What are Nissl bodies?

Answer 24

Granular areas
Site of protein synthesis

Question 25

Where are nissl bodies most abundant?

Answer 25

Large nerve cells (eg. motor neurones)

Question 26

Decribe chromatolysis

Answer 26

(chroma: colour; lysis: splitting)

Disintergration / Dispersal of Nissl Bodies following motor neurone injury