PBL 1 Flashcards
describe the structure of the cervix in terms of walls?
the internal os is between the uterus and cervix and the external os is between the cervix and vagina, with the endocervical canal in between
whats the histology of the exocervix?
stratified squamous epithelium
what’s the histology of the endocervix?
simple columnar epithelium
what is the squamocolumnar junction?
the precise histological transition between squamous and columnar epithelium
location is variable
when does the squamocolumnar junction move?
during early adolescence and the first pregnancy
where is the transformation zone of the cervix?
between the original and new squamocolumnar junctions
whats important about the transformation zone of the cervix?
its hormonally responsive and is a zone of metaplasia so is the usual site of cervical carcinoma
What types of cancer can strains of HPV cause?
cervical anus penis vagina vulva oropharynx
how is HPV transmitted?
sexually or through skin to skin contact e.g. pregnancy
what are 5 types of warts caused by HPV?
genital warts common warts plantar warts flat warts filiform warts
what are the key features of genital warts?
small califlower-like bumps on genitals
may be itchy or tender
what are the key features of common warts?
rough, raised bumps on hands or fingers
can be painful and bleed
what are the key features of plantar warts?
hard, grainy growths on heels or balls of feet that may cause discomfort
what are the key features of flat warts?
flat-topped slightly raised lesions mainly on face (kids), beard area (men) and legs (women)
what are the key features of filiform warts?
long projections of the skin often around eyes or lips (also called digitate or facial warts)
what is respiratory papillomatosis?
a wart-like growth or tumor on the surface of the larynx caused by HPV
what are the symptoms of respiratory papillomatosis?
voice changes high pitched breath sounds coughing choking snoring dysphagia
what are the 2 types of HPV infection?
cutaneous (skin) or mucosal
outline the pathophysiology of HPV?
cuts can allow the virus to reach the basal cell layer of stratified squamous epithelial cells. The infection of basal cells stimulates cellular proliferation in the basal layer through their 2 viral genes; E6 and E7. This leads to uncontrolled cell growth of epithelial cells forming warts and lesions and an icnreased viral load as it copies itself. Infected cells move up through the skin layers, reaching the top and releasing new viruses.
what do E6 and E7 do?
E6 oncoprotein inhibits p53’s tumour suppressor function whilst E7 binds to the retinoblastoma tumour suppressor gene (pRb) product inhibiting it so that cell growth cant be inhibited.
what are koilocytes?
cells with irregular shapes, enlarged and dark staining nucleus and a paranuclear halo
what does dyskaryosis mean?
the change of appearance in cells that cover the surface of the cervix
what does the transformation of pre-cancerous lesions to cervical carcinomas depend on?
HPV type
length of infections
cofactors e.g. tobacco use, immunosuppression
why is smoking a risk factor for cervical cancer?
tobacco by-products have been found in the cervical mucus of women who smoke. It’s thought that these substances damage the DNA of cervical cells