Histology

Question 1

what are the 4 types of tissue found in the human body?

Answer 1

• epithelium
• connective
• nervous
• muscle

Question 2

All epithelia are arranged as continuous sheets of tightly bound cells, what is the function of this?

Answer 2

• protection against microbial invasion
• regulation of movement of substances

Question 3

How can the structure of epithelial tissues be described?

Answer 3

• continuous sheets of cells
• tightly bound together
• polarised

Question 4

What shapes can epithelial cells be?

Answer 4

• squamous
• cuboidal
• columnar

Question 5

What is the name of a single layer of epithelial cells?

Answer 5

simple epithelium

Question 6

What name is given when there are two or more layers of epithelial cells?

Answer 6

stratified epithelium

Question 7

What is the function of microvilli sometimes found on epithelial cells?

Answer 7

increase apical surface area

Question 8

What is the function of cilia on epithelial cells?

Answer 8

movement of particulate matter

Question 9

What is the function of a keratin layer on epithelial tissues?

Answer 9

strong protective apical layer

Question 10

What epihelium is found in the oral cavity?

Answer 10

stratified squamous (protects against mechanical abrasion)

Question 11

What can stratified squamous epithelium sometimes be that will enhance resistance to physical stress?

Answer 11

keratinised

Question 12

How do epithelial cells become keratinised?

Answer 12

• accumulation of keratin filaments as they mature
• formation of tough, non-living surface layer

Question 13

What is the proper term for a break in continuity of epithelium?

Answer 13

ulceration

Question 14

What type of epithelium does a squamous cell carcinoma originate from?

Answer 14

stratified squamous epithelium

Question 15

where does cell division take place within epithelial cells?

Answer 15

basal & suprabasal cells (basal layer)

Question 16

What dense collagenous tissue supports the oral epithelium?

Answer 16

lamina propria

Question 17

How does the lamina propria differ in the oral cavity in terms of location?

Answer 17

Highly mobile areas (eg soft palate & FOM)
- loose submucosal supporting tissue

Oral mucosa that overlies bone (eg hard palate)
- lamina propria is tightly bound to periostium

Question 18

How do the cells of a malignant tumour present histologically?

Answer 18

• pleomorphism (variation in cell shape & size)
• numerous mitoses
• abnormal mitoses
• variable differentiation

Question 19

What is the difference between LM (light microscopes) and EM (electron microscopes)?

Answer 19

Light microscopes = reveal basic cellular structure, resolution is 0.2microM

Electron microscopes = reveal ultrastructure, resolution is 1nm

Question 20

What is the staining technique commonly used for histological practises?

Answer 20

H&E (haematoxylin & eosin)
- haematoxylin stains acidic structures blue/purple
- eosin stains basic structures red/pink

Question 21

Histologically, what cells are seen in bone tissue?

Answer 21

• osteoblasts (synthesises & secretes bone tissue, gives rise to osteocytes)
• osteocytes (maintains mineralised bone tissue)
• osteroclasts (resorbs bone)

Question 22

Describe the histological structure of skeletal muscle:

Answer 22

• individual muscle fibres separated by endomysium
• groups of muscle fibres grouped together in fasciculi
• each fasciculi surrounded by loose connective tissue (perimysium)
• entire muscle is externally surrounded by dense connective epimysium
• BV & nerves spread throughout these tissues

Question 23

Name 2 classifications of neoplasia & their subgroups?

Answer 23

CLINICAL: benign / malignant

HISTOLOGICAL: epithelial / mesenchyme

Question 24

How can histology help grade tumours?

Answer 24

Histological assessment of:
- invasion into underlying tissue
- degree of cellular atypia (mitotic activity, nuclear pleomorphism, differentiation, necrosis)

Question 25

How does histology of a benign tumour present?

Answer 25

• resembles tissue of origin
• uniform cell/nuclear shape & size
• few mitoses

Question 26

How does histology of a malignant tumour present?

Answer 26

• variable resemblance to tissue of origin
• cellular & nuclear pleomorphism
• many mitoses, abnormal

Question 27

How does the mucosa of the cheek look histologically? (in reference to keratin)

Answer 27

NON-KERATINISED

Question 28

How does the mucosa of the hard palate look histologically? (in reference to keratin)

Answer 28

KERATINISED (band along the top)

Question 29

What do each of these arrows point to?

Answer 29

1. Keratosis
2. Acanthosis (hyperplasia of stratum spinosum)
3. Elongated rete ridges (hyperplasia of basal cells)

Question 30

What do these arrows point to?

Answer 30

Giant cells

Question 31

What are the histological layers of epidermis?

Answer 31

• stratum coneum
• stratum granulosum
• stratum spinosum
• stratum basale
• dermis

Question 32

What are the basic layers of mucous membranes histologically?

Answer 32

• epithelium
• lamina propria

Question 33

What cells are found in the lamina propria?

Answer 33

• Fibroblasts
• Immune cells

Question 34

What is found in the ECM of lamina propria?

Answer 34

• collagen
• elastin fibres

Question 35

What are the gross types of oral mucosa?

Answer 35

• lining (buccal, soft palate)
• masticatory (hard palate)
• gustatory (tongue [specialised])

Question 36

What are the functions of oral mucosa?

Answer 36

1. Protection = barrier to microorganism
2. Sensation = receptors that respond to touch, taste, pain etc
3. Secretion = salivary glands
4. Permeability & Absorption = feature utilised in drug delivery

Question 37

How does a low-grade oral mucosa dysplasia present histologically?

Answer 37

• considerable amount of keratin production
• evidence of stratification
• well formed basal cell layer
• tumour islands are well defined & usually continuous with surface epithelium

Question 38

How does a high-grade oral mucosa dysplasia present histologically?

Answer 38

• shows little resemblance to normal squamous epithelium
• considerable atypia
• invasion of surrounding tissues
• mitotic figures are prominent