Simple columnar epithelium
Epithelium simplex columnare
Also known as: columnar epithelium, enterocytes, ciliated columnar epithelium
A single layer of tall cells with elongated, basally located nuclei, lining most of the digestive tract (non-ciliated, often with microvilli and goblet cells) and parts of the female reproductive tract (ciliated).
Overview
The cells are taller than wide and their oval nuclei are aligned near the base, forming a neat row. Their abundant cytoplasm accommodates the organelles needed for absorption and secretion.
Non-ciliated simple columnar epithelium lines the digestive tract from the stomach to the anal canal (above the pectinate line), the gallbladder and larger glandular ducts. In the stomach every surface cell is a mucus-secreting surface mucous cell; in the small intestine absorptive enterocytes with a striated border of microvilli are interspersed with mucus-secreting goblet cells, which become more numerous toward the colon. Ciliated simple columnar epithelium lines the uterine tubes, where cilia beat toward the uterus, as well as parts of the uterus, the smallest bronchi and the central canal of the spinal cord (ependyma).
- Location
Stomach, small and large intestine, gallbladder, ducts of large glands (non-ciliated); uterine tubes, uterus, small bronchi (ciliated).
Anatomy
- Histology
Tall cells, basal oval nuclei in one row; apical striated border (microvilli) or cilia; pale mucin-filled goblet cells (PAS-positive).
Function
- Absorption (enterocytes).
- Secretion of mucus and enzymes.
- Propulsion by cilia (uterine tube).
- Protective mucus barrier (stomach).
Clinical significance
Barrett oesophagus
Chronic gastro-oesophageal reflux replaces the stratified squamous epithelium of the distal oesophagus with intestinal-type columnar epithelium containing goblet cells — a metaplasia that predisposes to oesophageal adenocarcinoma.
Coeliac disease
Gluten-driven inflammation causes villous atrophy, crypt hyperplasia and intra-epithelial lymphocytosis, reducing the absorptive enterocyte surface.
Ectopic pregnancy
Damage to the ciliated epithelium of the uterine tube (e.g. after pelvic inflammatory disease) delays transport of the embryo, which may implant in the tube.
Test yourself
The trachea is lined by:
- Simple columnar epithelium with microvilli
- Stratified squamous non-keratinised epithelium
- Pseudostratified ciliated columnar epithelium with goblet cells
- Simple cuboidal epithelium
Answer: Pseudostratified ciliated columnar epithelium with goblet cells
"Respiratory epithelium": all cells touch the basement membrane but not all reach the lumen, so nuclei lie at different levels. Cilia and goblet-cell mucus form the mucociliary escalator.
SGLT1 in intestinal enterocytes is an example of:
- Facilitated diffusion
- Primary active transport
- Secondary active transport (symport)
- Receptor-mediated endocytosis
Answer: Secondary active transport (symport)
SGLT1 couples the downhill entry of 2 Na⁺ to uphill entry of glucose (or galactose). The Na⁺ gradient is maintained by the basolateral Na⁺/K⁺-ATPase; glucose leaves via GLUT2 by facilitated diffusion. This is the basis of oral rehydration solution.
Compiled from standard anatomy and physiology references — see the Cells & Tissues sources. For education only; not medical advice.