AN52.1-8 | Histology & Embryology (Abdomen & Pelvis) — Glossary

Oxyntic cell in the gastric fundus/body producing hydrochloric acid and intrinsic factor (essential for vitamin B12 absorption)

Peptic cell in the gastric fundus/body producing pepsinogen, the inactive precursor of the protein-digesting enzyme pepsin

Gastrin-secreting endocrine cell in the pyloric antrum; gastrin stimulates parietal cells to produce HCl

Submucosal glands unique to the duodenum secreting alkaline mucus to neutralise acidic chyme from the stomach

Aggregated lymphoid follicles in the ileal submucosa; part of the gut-associated lymphoid tissue (GALT) for immune surveillance

Resident macrophages lining hepatic sinusoids; phagocytose bacteria, old red blood cells, and debris from portal blood

Ito cells in the hepatic space of Disse that store vitamin A; when activated in liver disease, they produce collagen causing fibrosis and cirrhosis

Functional unit of the liver centred on the portal triad; zone 1 (periportal) has the best oxygen supply, zone 3 (centrilobular) is most vulnerable to ischaemia

Cell unique to the pancreatic exocrine acinus, located at the centre of the acinus; secretes bicarbonate-rich fluid

Endocrine clusters in the pancreas: beta cells (insulin), alpha cells (glucagon), delta cells (somatostatin)

Major embryological source of the diaphragm forming the central tendon; derived from cervical somites C3-C5, hence the phrenic nerve

Most common congenital diaphragmatic hernia (90%); left posterolateral defect from failure of the pleuroperitoneal membrane to close

Incomplete 270-degree rotation of the midgut around the SMA; caecum remains high with Ladd's bands across the duodenum, risk of midgut volvulus

Congenital aganglionosis — failure of neural crest cells to migrate to the distal colon; rectosigmoid most commonly affected; causes functional obstruction

Remnant of the vitellointestinal duct; true diverticulum on the anti-mesenteric border of ileum; may contain ectopic gastric or pancreatic mucosa

Fusion of the inferior poles of both kidneys; ascent arrested at L3 by the IMA; usually asymptomatic but increased risk of infection

Urethral opening on the ventral surface of the penis from failure of urethral folds to fuse; most common penile anomaly

Undescended testis — failure of testicular descent from posterior abdominal wall to scrotum; risk of infertility and testicular malignancy

AMH — secreted by Sertoli cells in the embryonic testis; causes regression of the Mullerian (paramesonephric) duct in males

Endocrine structure formed from the ruptured ovarian follicle after ovulation; produces progesterone to maintain the endometrium

Visible junction at the cardio-oesophageal junction where stratified squamous (oesophageal) epithelium meets simple columnar (gastric) epithelium

Midline anterior abdominal wall defect at the umbilicus with sac-covered herniation of viscera; associated with chromosomal anomalies

Paraumbilical defect (usually right) with uncovered bowel herniation; not associated with chromosomal anomalies