EPITHELIAL DEFECTS+DISEASE Flashcards
how are epithelium exposed to the environment?
skin
where are epithelium found?
Respiratory tract Digestive tract Reproductive system Circulatory system Urinary system Glands
what are pathologists?
Physicians - study of disease processes – diagnosis rather than treatment
what do disease processes do?
affect the histological organisation of tissues & organs – biopsy
what are squamous cell carcinoma?
atypical squamous cells
what is a response to injury?
inflammation
Kills cells, damage fibres, injures tissue
Necrosis
what does inflammation cause?
impact, abrasion, distortion, chemical irritation, extreme temperature – infection –pathogenic organisms
what is necrosis?
tissue degeneration (lysosomal enzymes), dead/dying cells, debris, fluid, necrotic tissue components (pus)
what is the effect of age on tissue repair?
Tissues change with age & speed/ effectiveness of tissue repair decreases
Structure & chemical composition many tissues effected e.g. epithelia get thinner
Cancer rates increase with age
what are the most common cancers in women?
breast, ling, colorectal
what are the most common cancers amongst men?
prostate, lung, colorectal
what does ageing affect?
cell degeneration, number of cell divisions, DNA repair, free radical damage
what is dysplasia?
enlargement of an organ/tissue by the proliferation of cells of an abnormal type
when does dysplasia usually occur?
Most frequently arises in epithelial tissues subjected to chronic irritation
what does dysplasia cause?
Cells exhibit high nuclear to cytoplasmic ratio
Increase number of cell mitoses
Leads to neoplasm - malignancy
where does dysplasia progress?
squamous epithelium, epidermis, colonic mucosa, gastric mucosa, resp epithelium
what is metaplasia?
Tissue adapts to environmental stimuli by change in cell differentiation
Abnormal change in the nature of a tissue
what cells differentiate into in metaplasia?
into a new, mature, stable type of cell better equipped to withstand particular environmental stress
where does metaplasia most commonly occur?
in epithelial tissue
give examples of metaplasia
bronchi, cervix, bladder
what is neoplasm?
Permanent alteration of normal cellular growth pattern – transformed cells
what does neoplasm cause?
Proliferate excessively in poorly regulated manner – lump – neoplasm “new growth”
what are the 2 types of neoplasm?
Benign (good prognosis)
Malignant (fatal)
what does a neoplasm lump also known as?
tumour
what happens in malignant neoplasms?
Cell growth so abnormal – cells can grow into adjacent local tissues – invasion
what do malignant neoplasm cause?
tissue – damage & destruction
what happens to cells in malignant neoplasm?
Cells can become detached, move to another part of body or
grow as separate secondary tumour
what is the growth of a separate secondary tumour called?
metastasis
what are benign tumours?
differentiation closely resembles cells of origin
what are malignant tumours?
variable degrees of differentiation
what are the different types of malignant tumours?
Well-differentiated, Poorly differentiated, Anaplastic
what is the epithelial origin of benign neoplasm?
solid & surface epithelium – adenoma
what is the epithelial origin of malignant neoplasm?
carcinoma
glandular epithelium – adenocarcinoma
is dysplasia reversible or irreversible?
reversible
what are the histological changes caused by dysplasia?
Change in normal shape, size & organisation of tissue cells
is metaplasia reversible or irreversible?
reversible
what are the histological changes caused by metaplasia?
Structural change Epithelial cells lose cilia altogether New cells (stem cells) no longer differentiate into ciliated, columnar epithelial cells
is anaplasia reversible or irreversible?
irreversible
what are the histological changes caused by anaplasia?
Tissue organisation breaks down
Cells change size & shape and become unusually large or small
Tumour cell – lung cancer
what is atherosclerosis?
Thickening & inelasticity of artery walls
what does the pathogenesis of atheroma cause?
damage to endothelium – allows LDLs into the intimate –”fatty streak”
what are the risk factors of atherosclerosis?
age, sex, hyperlipidaemia, hypertension, diabetes mellitus, smoking
what is the skin?
Large complex organ – exposed to more damaging agents than any other tissue
what is non-specific dermatitis also known as?
eczema
what does eczema cause?
Skin- red, itchy, tender – tiny blisters – vesicles form in epidermis
what happens to vesicles in eczema?
Vesicles erupt - clear, yellow fluid, crusts over
Vesicles due to fluid accumulation between epidermal cells
what is chronic dermatitis?
Repeated trauma - thickened skin, cracked, covered by thick opaque scale
what is the opaque scale thickened by?
by layer surface keratin – overlies epidermis
what is the epidermis thickened by?
by increase in cells in various layers
