L8 Introduction to Microscopic Anatomy

Question 1

Histology provides information about… [5]

Answer 1

• Diagnosis 
	• Prognosis 
	• Likelihood of treatment efficacy 
	• Effect of treatment
Incidental findings

Question 2

What is Processing?

Answer 2

• Processing into a wax block 
	• Fixation 
	• Alcohol removes water 
	• Xylene removes alcohol 
Paraffin removes xylene

Question 3

What is the H & E Stain?

Answer 3

Purple: Haematoxylin in nucleus

Red/pink: Eosin in cytoplasm

Question 4

PAS

Answer 4

Neutral mucin, BM, fungal organisms, collagen and glycogen

Question 5

Alcian blue

Answer 5

acidic mucin

Question 6

Trichrome stains

Answer 6

collagen and elastin

Question 7

Prussian blue

Answer 7

Iron

Question 8

Warthin Starry

Answer 8

Spirochaetes

Question 9

Immunohistochemistry

Answer 9

• Detect proteins on/in cells or tissues
• Antibody labelled with a brown dye
○ Brown slide = protein present
Background stain only (blue) = protein absent

Question 10

S100 protein positive

Answer 10

granular cell tumour confirmed (antibody against S100 labelled with brown chromogen)

Question 11

Epithelium

Answer 11

• Cells covering a surface, underlying BM
• Interface between biological compartments
• May originate from: Ectoderm, mesoderm and endoderm
• Ingrowths of epithelium specialise to form glands and ducts
Protective barrier, regulation of molecular exchanges, synthesis and secretion of glandular products

Question 12

Epithelium structure

Answer 12

• Cells are polarised basal/apical
• Basement membrane (collagen)
• Adherent to each other, tight junctions seal borders, desmosomes for strength, gap junctions to allow molecule transfer
Cytokeratin intermediate filaments with cytoplasm to provide internal structure (immunohistochemistry)

Question 13

Glandular/Columnar epithelium

Answer 13

Glandus are formed from special columnar epithelial cells with secretory function
• Some have ducts: Exocrine glands (salivary, breast, exocrine pancreas)
• Some don’t have ducts: Endocrine glands secrete directly into vascular system (thyroid, adrenal, islets of Langerhans)

Tubular exocrine glands - simple or compound
Acinar exocrine glands - simple or compound

Question 14

Endocrine

Answer 14

• Anterior pituitary 
	• Thyroid 
	• Parathyroid 
	• Pancreas 
Adrenal glands

Question 15

Histology of BVs

Answer 15

• Tunica intima: simple layer of endothelium + loose CT
• Lamina elastica interna: Elastin
• Tunica media: circumferential SM
• Lamina elastica externa: Elastin
Tunica adventitia: Collagen and little arteries/veins/nerves to supply vessel wall

Question 16

Types of arteries

Answer 16

• Elastic arteries: Aorta, brachiocephalic trunk, Common carotid, subclavian, large pulmonary arteries (large calibre)
• Muscular arteries: main distributing branches eg radial, femoral, cerebral and coronary (medium calibre)
Arterioles (small calibre)