Intestine Flashcards
Small intestine: Circular folds of the mucosa and submucosa which increase the surface area of the and decrease the velocity of he movement of the luminal contents
Plicae circulares
Small intestine: Finger-like protrusions of the lamina propria covered by tightly packed absorptive cells
villi
Small intestine: Structural modifications to the apical cell membrane of epithelial cells, increasing the available surface area for absorption
Microvilli
Small intestine: Invaginations of the epithelium into the lamina propria
Crypts of Lieberkuhn
Small intestine: Secrete mucus to protect lumen from stomach acid and traumatic damage
Goblet cells
Small intestine: Hormone releasing cells within gut epithelium
Endocrine cells
Small intestine: Pyramid shaped cells found at the base of small intestinal crypts. Produces products that are important in protecting the intestinal epithelium against microbes
Paneth cells
Small intestine: Branched tubuloalveolar glands with mucous-secreting acina located primarily in the duodenal submucosa. Secretes a bicarbonate rich fluid which neutralises acidic chyme
Brunner’s glands
Small intestine: Aggregation of plasma cells, lymphocytes, mast cells, leucocytes and fibroblasts found throughout the small intestine
Lymphoid tissue(known as Peyer’s patches in terminal ilium)
Large intestine: The mucosa is devoid of villi, instead it is rich in ………… which are similar to those in the small intestine except for the absence of Paneth cells and a larger amount of ……………
Crypts and Goblet cells
Congenital disorder which presents soon after birth. Diagnosed on the basis of persistent vomiting of bile-containing fluid and failure to pass meconium. Most commonly found in the duodenum or small intestine and rarely in the colon
Atresia(complete occlusion) and stenosis(incomplete obstruction)
An obstruction caused by twisting of the stomach or intestine
Volvulus
Outpouching of the ileum on approximately 60 to 100cm from the ileocaecal valve. Caused by the incomplete regression of the vitelline duct.
Meckel’s diverticulum
An instance of the inversion of one portion of the intestine within another
Intussusception
Intestinal aganglionosis results from a failure of neuroblasts to migrate from the vagus into the developing gut. Under normal circumstances parasympathetic tone is modulated within the ganglia by sympathetic innervation. With the absence of myenteric ganglia the parasympathetic supply is left unchecked leading to spasm of the circular muscle and intestinal obstruction
Hirschsprung’s disease
Chronic inflammation resulting from sensitivity to gluten components in cereals. Damage to he surface enterocites of the small intestine severely reduces their absorptive capacity. Causes vilous atrophy, crypt hyperplasia and intraepithelial lymphocytosis in duodenal or jejunal biopsy. Results in malabsorption, weight loss and iron-deficiency anaemia
Coeliac disease
Progressive malabsorption syndrome seen in patients who live/have lived in the tropics. Thought to be secondary to bacterial contamination of the small bowel. Histologically resembles coeliac disease. Unlike coeliac disease, symptoms do no improve upon removal of gluten. Prognosis is very good as long as the correct diagnosis is made, usually treated with tetracycline and folate for 6 months
Tropical sprue
Gram-positive bacillus which is non-invasive but produces a toxin which is responsible for enteritis. Some patients taking a broad spectrum antibiotic develop diarrhoea resulting from the overgrowth of this commensal bacterium
Colostridium difficile enteritis
Many drugs affect the GI tract but due to their widespread use ………. are the most important. Longer term use can lead to small bowel ulceratiuon and strictures. Occasionally ulceration can occur in caecum and proximal colon
Non-steroidal anti-inflammatory drugs (NSAIDs)
