T1 pathology Flashcards by Joanna MacInnes

What percentage of the bodyweight constitutes skin?

15%

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What are the functions of keratinocytes?

to provide mechanical protection

to constitutes to the main cell block of the skin

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What are the functions of melanocytes?

to produce melanin pigment - to provide UV-light protection

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What are the functions of langerhans cells?

to provide immune cells in the skin to protect against the millions of bacteria living on our skin
to act as immune sentinels
to conduct phagocytosis

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What are the functions of merkel cells?

sensory function (light touch)

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When are p40 marker present?

a marker of the nuclear features of keratinocytes

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What does p63 marker indicate?

a tumor protein marker on the cells of the breast ducts and nodes

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What does a CK5/6 marker indicate?

the presence of lung and breast cancers

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Where is the CK14 marker normally expressed?

in the basal cells of squamous epithelium

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Where are melanocytes located?

in the epidermis

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What is the relationship between melanocytes and keratinocytes?

One melanocytes delivers melanin to 36 keratinocytes.

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What are the cell layers of the epidermis?

stratum corneum - horn
stratum lucidium - clear
stratum granulosum - granular
stratum spinosum - prickle
stratum basalis - basal

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How is the presence of melanomas confirmed?

by performing a reaction against the s100 marker for neural cells and melanomas

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Where do langerhans cells originate from?

the bone marrow

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What is the function of langerhans cells?

function as immune sentinels as APCs

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What is the basement membrane made up of?

Collagen type IV

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What is the basement membrane highlighted by?

PAS stain

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What is the dermis made up of?

dense connective tissue - collagen, elastin, extracellular matrix

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What does the dermis contain?

nerves
blood vessels
lymphatics
histiocytes
mast cells
plasma cells
lymphocytes
mechanoreceptors
thermoreceptors 
subcutaneous fat

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What are the two skin appendages in the dermis?

Pilosebaceous units (hair) 
sweat glands

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What are the two levels for blood vessels?

superficial area of the dermis

the reticular dermis

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What is the difference between the secretions of the eccrine glands and those of the apocrine glands?

eccrine - watery secretion

apocrine - more oily secretion

How does a blister occur?

when the epidermis comes off because it is no longer bound to the dermis underneath

What are two examples of autoimmune diseases

that cause severe blistering diseases of the skin?

bullous pemphigoid

dermatitis herpetiformis

Which parts of the body are apocrine glands found?

axilla groin nipple

What are the four types of cells of the epidermis?

keratinocytes melanocytes langerhans cells merkel cells

Which organs are lined by non-keratinised squamous epithelium? (MOVAC)

``` mouth oesophagus vagina anal canal cervix ```

What is the function of the enzyme tyrosinase?

to produce melanin

What is albinism caused by?

a lack of tyrosinase

What are the major types of skin cancer?

malignant melanoma squamous cell carcinoma basal cell carcinoma

What are all skin cancers are associated with?

excess sun exposure

What parts of the body do malignant melanomas have the potential to spread to?

lymph nodes lungs liver brain

How is the prognosis of all cancers assessed?

using the TNM stage

What does TNM look at in the prognosis of cancer?

``` T = tumour size or depth of invasion N = node (whether there is lymph node metastasis or not) M = metastasis to the liver, lung, bone etc. ```

What are the three classifications of squamous cell carcinoma?

Well differentiated – when the cancer cells produce lots of keratin Moderately differentiated – moderate amount of keratin Poorly differentiated – little or no keratin i.e. graded on how closely the cancer resemble skin

Which is the most common cancer of the skin in the Western world?

Basal Cell Carcinoma (BCC)

Which three cell types are responsible for proliferation ability?

LABILE CELLS - continuously proliferate STABLE CELLS - good regenerative ability but would normally have a low cell turnover unless injury PERMANENT CELLS - very little or no regenerative ability

What are the causes of cell injury?

``` mechanical trauma metabolite deprivation - hypoxia, ischaemia, nutrients, vitamins nutritional excess temperature pressure radiation electricity chemicals toxins infectious agents immune reactions genetic changes ```

What does Sola dosis facit venenum mean?

the dose makes the poison

What is hypertrophy induced by?

PI3K/AKT pathways | G-coupled pathways

What types of hypertrophy are there?

physiological - hormonal or compensatory hormone stimulated pathological - cardiac or bladder

What is the cause of cardiac hypertrophy?

stenosis of the aortic valve - inability to move the aortic valve due to calcification causes obstacle to pumping blood out of the left ventricle

What is the cause of bladder hypertrophy?

the prostate is often enlarged in older men this causes an obstacle for the outflow of urine from the detrusor muscle therefore, trabecular hypertrophy of the bladder muscles is triggered

What is the difference between hyperplasia and hypertrophy?

in hypertrophy, it is the true cell number that increases

Why is hyperplasia restricted to certain cells?

because the cells have to be able to divide

What two cell types can hyperplasia occur in?

labile cells | stable cells

Which cell type will hyperplasia not occur in?

so terminally differentiated cells can no longer undergo hyperplasia

What is hyperplasia induced by?

growth factor activation | stem cell activation

What happens during hormonal hyperplasia?

hormones change the internal environment | they trigger adaptive processes of hyperplasia and resultant hypertrophy

What is an example of hormonal hyperplasia and how does it work?

breast feeding the breast undergoes high hyperplasia the breast terminal duct lobular units undergo hyperplasia to produce milk

What is an example of compensatory hyperplasia | and how does it work?

liver lobectomy performed when tissue is lost a liver lobe is removed the remaining liver is able to replace this lost tissue and practically grow back to normal size

Which hormone is responsible for influencing lactation in the breasts?

prolactin

What is the difference between hyperplasia and neoplasia?

hyperplasia - increased cell numbers due to physiological / pathological conditions and is reversible neoplasia - unregulated cell proliferation due to genetic changes

What types of atrophy are there?

physiological atrophy | pathological atrophy