- Cheeks
- Epithelium - Glycogen rich non-keratinising stratified squamous
- Submucosa - minor buccal salivary glands, sebaceous glands - Fordyce's spots
- Deep muscle - buccinator
- Palate
- Palatine salivary glands
- Hard palate - non-keratinising epithelium prominent rete ridges
- Soft palate - transitions to ciliated columnar at posterior edge
- Floor
- Minor and major sublingual salivary glands
- Tongue
- Muscular organ
- Ventral surface - thin non-keratinising sq. epithelium continuous with floor
- Dorsal - specialised keratinising squamous epithelium
Alimentary Canal Histology
Introduction
- Function: break down food into absorbable particles
- Muscular tube lined by variable epithelium
- Structure of musculature similar throughout
Lips
Oral Cavity
Transition between dry, hair-bearing skin and moist mucosa
Oesophagus
- Non keratinising stratified squamous epithelium
- Glycogenated
- Basal zone several cell layers thick, non glyconenated
- Lamina propria
- Normal lymphocytes, eosinophils, mast cells, plasma cells
- Muscularis mucosae
- Submucosae
- Mucous glands
- Lymphoid tissue
- Nerves, blood vessels, lyphatics
- Muscularis propria
- Circular, longitudinal
- Upper third striated, middle third mixed, lower third smooth and continuous with stomach
Aufar Bahri
Stomach
Gastro-Oesophageal Junction
- Glandular architecture
- Epithelium secretes
- Mucus
- Hydrochloric acid
- Digestive enzymes
- Cell types
- Mucous (surface/neck)
- Acid-producing (oxyntic/parietal)
- Enzyme producing (chief/peptic)
- Stem cells
- Neuroendocrine cells
- Three layers of muscle
- Divided into cardia, body and pyloric regions
- Important site of pathologic abnormality
- Squamo-columnar junction
- Lymphoid aggregrates, mucous glands prominent
Cardia
Body
Pyloric
Duodenum
- Villous architecture to increase surface area
- Crypts extend to muscularis mucosae
- Villi:Crypt = 2:1
- Cell types:
- Enterocyte
- Mucous (Goblet) cells
- Paneth cell
- Endocrine cell
- Stem cells
- Submucosal Brunner's glands
Jejunum/small bowel cont.
- Small bowel lamina propria
- Blood vessels, lymphatics (lacteal)
- Lymphocytes, plasma cells, eosinophils, macropages, mast cells
- Submucosa
- Ganglion cells/nerve plexus
Colon
- Tubular achitecture
- Mucosa specialised for water and salt reabsorption and mucus secretion
- Cell types:
- Columnar (absorptive) cells
- Mucous (Goblet) cells
- Endocrine cells
- Stem cells
- Paneth cell in caecum and appendix
Ileum
Well developed lymphoid aggregates - Peyer's patches
The End