Histology Flashcards
What parts of the oral cavity and pharynx are covered by respiratory epithelium?
Oral cavity, oropharynx and layrngopharynx.
What parts of the oral cavity and pharynx are covered with respiratory epithelium?
Nasal cavity and nasopharynx.
How does the ventral and dorsal surfaces of the anterior 2/3rds of the tongue differ?
Both have stratified squamous epithelium, thin on ventral surface, thick and with papillae on dorsal surface.
What are the only papillae on the posterior 1/3rd of the tongue?
Circumvallate papillae.
What does the posterior 1/3rd of the tongue have in the submucosa?
Substantial lymphoid aggregates.
Describe the histology of the gastro-oesophageal junction.
Abrupt transition from stratified squamous epithelium of oesophagus to the columnar epithelium of the cardia of the stomach.
What are at the bottom of the gastric pits?
Gastric glands.
What lines the gastric pits?
Surface mucous cells.
What are the regions of the gastric gland going down?
Pit -> isthmus -> neck -> base.
What cells do each of these regions contain?
Isthmus - parietal. Neck - mucous cells and stem cells. Base - chief cells, few parietal cells and enteroendocrine cells (neuroendocrine cells).
Describe the mucosa of the cardia.
Deep gastric pits that branch into loosely packed, tortuous glands.
Describe the mucosa of the body.
Shallow gastric pits with long straight gastric glands.
Describe the mucosa of the pylorus.
Deep gastric pits with branched, coiled gastric glands at higher density than in the cardia.
Where is the extra layer of the stomach muscularis externa?
Internal to the circular layer.
What is the orientation of the muscle fibres of the extra layer of stomach muscle and what is its function?
Oblique, aids the churning action of the stomach.
What layer of muscle is thickened at the gastroduodenal junction and why?
Inner, circular layer. Forms the pyloric sphincter.
What are the crypts called in the small intestine?
Crypts of Lieberkuhn.
What glands does the duodenum contain in the submucosa?
Brunner’s glands.
What part of the small intestine has the tallest villi?
Jejunum.
What are the folds on the jejunum called and what layers are they made up of?
Plicae circulares. Mucosa and submucosa.
What is the lymphoid tissue present in the submucosa of the ileum?
Peyer’s patches.
What are the cells in the small intestine epithelium?
Eneterocytes, goblet cells, paneth cells, enteroendocrine cells, stem cells.
Where are paneth cells found and what do they do?
Found at the base of the crypts of Lieberkuhn, defensive function and regulate bacterial flora (secrete lysozyme and defensins).
What are the hormones secreted from enteroendocrine cells in the small intestine?
Gastrin, cholecystokinin (CKK), vasoactive intestinal peptide (VIP).
Where are the stem cells in the small intestine found?
The base of the crypts of Lieberkuhn.
What do Brunner’s glands secrete?
A thin, alkaline mucous to neutralise the chyme.
What are the 2 principle types of cells in the large intestine?
Absorptive cells, goblet cells.
How far do the crypts of the large intestine go down?
To the muscularis mucosae.
How is the longitudinal smooth muscle of the large intestine arranged?
In 3 muscular strips called teniae coli.
What are the differences between the structures of the appendix and the rest of the colon?
Crypts are far less abundant in appendix, has a circular arrangement of lymphoid tissue in the submucosa and often the lamina propria (declines with age).
Where does the mucosa turn back into stratified squamous epithelium?
At the rectoanal junction.
What are the 2 plexuses of the enteric nervous system?
Myenteric plexus and submucosal plexus.
