OP05 oral hyperplasia Flashcards
(62 cards)
What are the 3 types of cells involved in tissue repair and regeneration?
Labile cells, stable cells, permanent cells
What are labile cells?
Proliferate continuously throughout post-natal life, high regenerative capacity: bone marrow, epithelia of mouth, skin, gut and bladder. Susceptible to toxic agents such as anti-cancer chemotherapy drugs and radiation.
What are stable cells?
Divide only infrequently but can be stimulated to divide when cells are lost: bone, liver, renal tubular cells, fibroblasts in connective tissue
What are permanent cells?
Normally only divide in embryonic, fetal and maybe early post-natal life. Cannot be replaced when lost as only have limited capacity to divide: cardiac muscle cells, retinal photoreceptors, neurones
What are the 4 types of adaptation that change the cell but preserve vitality in response to cell stress?
Hyperplasia
Hypertrophy
Atrophy
Metaplasia
Brief definitions slide of many terms
o Aplasia: “no growth”, lack of development of a tissue
o Hyper / hypoplasia: increase / decrease in the number of cells
o Hyper / hypotrophy: increase / decrease in the size of cells
o Metaplasia: ”other growth”, differentiation from one mature type into another mature type
o Dysplasia: “wrong growth”, disturbance in the maturation of a tissue
o Anaplasia: lack of differentiation, of a tissue, characteristic of some tumour cells
o Neoplasia: “new growth”, a tumour, Willis’ definition
o Choristoma: normal tissue in the wrong location
o Hamartoma: abnormal amount of tissue in the right location
o Teratoma: malignant tumour containing tissues derived from all three embryonic layers.
What is hyperplasia?
Increase in the number of cells in response to a stimulus
When does hyperplasia often occur?
From increased demand/increased stimulation to growth factors, hormones etc. In tissues able to divide or that contain abundant stem cells.
What is hypertrophy?
Increase in the size of cells in response to a stimulus
What is metaplasia?
Differentiation from one mature type into another mature type. Occurs through altered differentiation pathway of tissue stem cells.
Is metaplasia bad?
Can predispose to malignant transformation
Is metaplasia reversible?
Sometimes if you remove the stimulus
Explain metaplasia in smokers
Respiratory tract (loss of mucus secretion and ciliary action - unfavourable change) - in smokers pseudostratified ciliated respiratory epithelium changes into squamous epithelium
What is dysplasia?
Disturbance in the maturation of a tissue. Cells lose the characteristics of the original tissue. No invasion.
What is atypia?
Deviations in morphology of cells
What is neoplasia?
A tumour
An independent, uncoordinated new growth of tissue, capable of unlimited proliferation and does not regress after removal of the stimulus which produced the lesion
Causes a permanent change in cells
Difference between benign and malignant neoplasms
Benign - innocent behaviour, localised lesion, without spread, amenable to surgical resection
Malignant - aggressive behaviour, invasion and destruction of adjacent tissue, capacity for spread to distant sites (metastasis)
What is differentiation of a tumour?
The extent to which cells resemble their ancestor - eg if you can tell what cells it originated from, it is well-differentiated; if you cannot tell its progenitor cells, it is undifferentiated.
How does differentiation of a tumour affect the prognosis of a neoplasm?
The less differentiated they are, the worse the prognosis for the patient.
What is anaplasia?
Lack of differentiation of a tissue, characteristic of some tumour cells.
What is choristoma?
Normal tissue in the wrong location ‘ectopic’ (not a neoplasm)
What is hamartoma?
Abnormal amount of tissue in the right location.
Disorganised but benign masses conmposed of cells indigenous to site.
Give examples of choristomas
Fordyce spots
Salivary gland choristomas
Osseous choristomas etc
Give examples of hamartomas
Odotomes
Haemangiomas
Torus palatinus
