Dr. ANAND SRINIVASAN
Able to : Describe, identify and draw the
histological features of : Small intestine Large intestine Rectum & Anal canal
Divided into duodenum, jejunum and ileum
Luminal surface is increased for absorption by Plica circulares (valves of Kerckring) Intestinal villi Microvilli
MUCOSA EPITHELIUM▪ Simple columnar epithelium with goblet cells ▪ Epithelium and lamina propria form intestinal
villi▪ Presence of glycocalyx for protection and
adsorption of pancreatic enzymes. ▪ Crypts of Lieberkuhn containing goblet cells,
columnar cells and Paneth cells▪ Paneth cells secrete lysozyme, located in base
LAMINA PROPRIA▪ Connective tissue
MUSCULARIS MUCOSA▪ Same as Gen. plan of GIT
SUBMUCOSA Shows regional variation Duodenum Brunner’s gland Ileum Peyer’s patches Jejunum None of the above
MUSCULARIS EXTERNA Same as Gen. plan of GIT
SEROSA Same as Gen. plan of GIT
Leaf like villi
Brunner’s glands (mucous, branched, coiled tubular) in submucosa opening into crypts.
Enteroendocrine cells secrete Urogastrone – inhibit HCl Secretin & Cholecystokinin – regulate
pancreatic secretion
Disrupted muscularis mucosae
Finger like villi
No glands or lymphatic nodules in submucosa
Thin and slender villiPeyer’s patches (aggregated
lymphatic follicles) in submucosa
Consists of Caecum, Appendix, Colon, Rectum and Anal canal
Absence of intestinal Villi
Has bacteria responsible for synthesis of Vitamin B12 & Vitamin K
Produces plenty of mucus that lubricates and facilitates easy passage of faeces
Gen. histological features of small intestine with following modifications No Villi Few short crypts Small lumen Lymphoid follicles in lamina propria Disrupted muscularis mucosae
Gen. histological features of small intestine with following modifications No Villi Well developed crypts with plenty of
goblet cells Paneth cells Absent Outer longitudinal layer of muscularis
externa modified into “Taenia coli” Fat filled pockets in serosa “Appendices
epiploicae”
Gen. histological features of small intestine with following modifications Long crypts of Lieberkuhn Lymphoid tissue less abundant in lamina
propria Absent Taenia coli Serosa replaced by adventitia in lower
part
Gen. histological features of small intestine with following modifications EPITHELIUM▪ Above anal valves – stratified cuboidal▪ At anal valves – stratified squamous non
keratinized▪ At anal orifice – stratified squamous keratinized
No crypts, No muscularis mucosae Inner circular layer thick anal sphincter Smooth muscle changes to skeletal muscle at
orifice
Wheater’s Functional Histology
Cell Biology & Histology – Board Review Series
Microanatomy workbook – RAKMHSU