4.04a Small and Large Intestine I Flashcards
4 layers of the small intestine
Mucosa
Submucosa
Muscularis externa
Serosa
Short tubular intestinal glands in the DUODENUM
Crypts of Lieberkuhn
Mucous duodenal glands that is a distinctive feature of the UPPER DUODENUM
Brunner’s glands
Outfoldings of the mucosa and submucosa that is extensive in the JEJUNUM
Plicae circulares (circular folds or valves of Kerckring)
Aggregated lymphatic nodules that are a characteristic feature of the ILEUM
Peyer’s patches
Differentiate MEISSNER’S PLEXUS and AUERBACH’S PLEXUS
Meissner: ganglion cells of the nerve plexus (submucosa)
Auerbach: ganglion cells of myenteric plexus (muscularis)
Differentiate OMPHALOCELE AND GASTROSCHISIS
Omphalocele: defect at the site of the umbilical cord insertion; sac replaces umbilical cord
Gastroschisis: right side of the umbilical cord insertion; absence of sac
Characteristics of Meckel diverticulum (hint: rule of 2s)
Present within 2 feet of the ileocecal valve
2 inches long
2x more common in males
Symptomatic by 2 y/o
What makes Meckel diverticulum a true diverticulum?
Composed of 3 intestinal layers (mucosa, submucosa, muscularis)
Communicates with intestinal lumen
What causes Hirschsprung disease?
Mutation in the tyrosine kinase receptor
Differentiate the ff:
Volvulus
Hernias
Adhesions
Intussusception
Volvulus: twisting of the bowel around the mesenteric root
Hernia: weakness or defect in wall of peritoneal cavity leading to protrusion of serosa-lined pouch of peritoneum
Adhesions: fibrous bridges
Intussusception: segment of the intestines telescopes into the immediate distal segment
Most common structures affected by volvulus (most to least common)
Sigmoid colon Cecum Small intestine Stomach Transverse colon
Most common sites of acquired hernia
Inguinal canal
Femoral canal
Umbilicus
Site of surgical scar
Differentiate INTUSSUSCEPTUM and INTUSSUSCIPENS
Intussusceptum: proximal segment constricted by peristalsis
Intussuscipens: immediate distal segment trapping the proximal segment
Most common type of intussusception
Ileocolic intussusception
Differentiate MUCOSAL, MURAL, and TRANSMURAL infarction.
Mucosal: hypoperfusion; mucosa
Mural: hypoperfusion; mucosa and submucosa
Transmural: obstruction; mucosa, submucosa, muscularis
Site of greatest risk of transmural infarction
Splenic flexure
Most common site of ANGIODYSPLASIA
Cecum and right colon
Gluten hypersensitivity. What is the allele they carry?
Celiac disease. HLA-DQ2 or HLA-DQ8
Screening test for celiac disease
IgA antibodies against tissue transglutaminase
adjunct: IgA anti-endomysial antibodies
Characteristic findings in celiac disease
villous atrophy and crypt hyperplasia
Patient is suspected of celiac disease. Where should biopsy be performed to confirm diagnosis? Why?
2nd part of duodenum or proximal jejunum. Exposed to highest concentration of gluten.
Direction of changes and healing in celiac disease.
Changes proximal to distal
Heals distal to proximal
Characteristic finding in Whipple disease
Foamy macrophages of the lamina propria of the small intestine (PAS-positive macrophages)
