Microscopic anatomy Flashcards
Define barrett’s oesophagus
Columnar cell lined lower oesophagus due to metaplasia; the oesophagus is lined by gastric mucosa, which can develop goblet cells in another process termed intestinal metaplasia.
What cells normally line the oesophagus?
Squamous cells
What is metaplasia?
Replacement of one mature type of cell with another
What causes the metaplasia in barrett’s syndrome?
Acid reflux
What is the OJG or Z line?
The place where squamous epithelium becomes columnar
What are the risk factors for barrett’s oesophagus?
High BMI Alcohol drinking Tobacco smoking Drugs which relaxes the lower oesophageal sphincter e.g. Nitroglycerins, Familial/genetic predisposition
Describe the pathogenesis of barrett’s oesophagus
Gastro-oesophageal reflux leads to reflux oesophagitis
Squamous epithelium changes to columnar epithelium in a process of metaplasia
The metaplastic process is an adaption to injury caused by the gastric contents
Columnar epithelium increases the risk of adenocarcinoma of the oesophagus through a precancerous stage called dysplasia
Describe the pathogenesis of barrett’s associated carcinoma
Metaplasia →dysplasia → adenocarcinoma sequence
Squamous epithelium ↓ Reflux oesophagitis ↓ Gastric epithelium ↓ Intestinal metaplasia ↓ Low grade dysplasia ↓ High grade dysplasia ↓ Adenocarcinoma
How does a patient with oesophageal cancer present?
Dysphagia - taking long time to eat and consume liquids while eating
Name 4 microscopic features of coeliac disease
Villus atrophy
Lymphocytic infiltration
Hyperplasia
Intraepithelial lymphocytes
Name 3 complications or other conditions associated with coeliac disease?
T cell lymphoma Infertility Diabetes Autoimmune hepatitis Dermatitis Cancer of small bowel and oesophagus
What does normal large bowel mucosa look like?
The crypts are arranged in a row reminiscent of test tubes
The goblet cells are full of mucin
The crypts are separated by the lamina propria with vessels and connective tissue
What are the indications for colectomy in UC?
Uncontrolled bleeding Toxic megacolon Dysplasia Cancer Patients not responding to treatment
What are the risk factors for dysplasia in ulcerative colitis?
UC at an early age
UC for over 8 -10 years duration→ screening colonoscopy annually
repeated bouts of acute inflammation with short periods of remission
total UC - involving the whole large bowel
What are the complications of crohn’s disease?
Peritonitis - shock
Fistula
Adhesions
Obstructions
