Histology Flashcards
what are the 4 types of tissue found in the human body?
- epithelium
- connective
- nervous
- muscle
All epithelia are arranged as continuous sheets of tightly bound cells, what is the function of this?
- protection against microbial invasion
- regulation of movement of substances
How can the structure of epithelial tissues be described?
- continuous sheets of cells
- tightly bound together
- polarised
What shapes can epithelial cells be?
- squamous
- cuboidal
- columnar
What is the name of a single layer of epithelial cells?
simple epithelium
What name is given when there are two or more layers of epithelial cells?
stratified epithelium
What is the function of microvilli sometimes found on epithelial cells?
increase apical surface area
What is the function of cilia on epithelial cells?
movement of particulate matter
What is the function of a keratin layer on epithelial tissues?
strong protective apical layer
What epihelium is found in the oral cavity?
stratified squamous (protects against mechanical abrasion)
What can stratified squamous epithelium sometimes be that will enhance resistance to physical stress?
keratinised
How do epithelial cells become keratinised?
- accumulation of keratin filaments as they mature
- formation of tough, non-living surface layer
What is the proper term for a break in continuity of epithelium?
ulceration
What type of epithelium does a squamous cell carcinoma originate from?
stratified squamous epithelium
where does cell division take place within epithelial cells?
basal & suprabasal cells (basal layer)
What dense collagenous tissue supports the oral epithelium?
lamina propria
How does the lamina propria differ in the oral cavity in terms of location?
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
How do the cells of a malignant tumour present histologically?
- pleomorphism (variation in cell shape & size)
- numerous mitoses
- abnormal mitoses
- variable differentiation
What is the difference between LM (light microscopes) and EM (electron microscopes)?
Light microscopes = reveal basic cellular structure, resolution is 0.2microM
Electron microscopes = reveal ultrastructure, resolution is 1nm
What is the staining technique commonly used for histological practises?
H&E (haematoxylin & eosin)
- haematoxylin stains acidic structures blue/purple
- eosin stains basic structures red/pink
Histologically, what cells are seen in bone tissue?
- osteoblasts (synthesises & secretes bone tissue, gives rise to osteocytes)
- osteocytes (maintains mineralised bone tissue)
- osteroclasts (resorbs bone)
Describe the histological structure of skeletal muscle:
- 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
Name 2 classifications of neoplasia & their subgroups?
CLINICAL: benign / malignant
HISTOLOGICAL: epithelial / mesenchyme
How can histology help grade tumours?
Histological assessment of:
- invasion into underlying tissue
- degree of cellular atypia (mitotic activity, nuclear pleomorphism, differentiation, necrosis)
