Flashcards in Histology Deck (62)
What are the four major layers of the digestive tract?
- muscularis externa
- serosa or adventitia
What is mucosa made of?
epithelium, lamina propria (connective tissue), basal lamina, muscularis mucosae
What is the submucosa made of?
loose connective tissue
What is the muscularis externa?
- circular smooth muscle
- longitudinal smooth muscle
What is the outer layer made of?
Name the two parts of the oral cavity that both have the same cell lining
oropharynx & larngopharynx - non keratinised stratified squamous epithelium
Name the cells lining the nasopharynx & nasal pharynx
How can the tongue be divided?
anterior 2/3 posterior 1/3
What cells line the anterior 2/3?
thin on ventral
thick on dorsal with papillae (tastebuds)
What cells line the posterior 1/3?
smooth stratified squamous epithelium with only circumvallate papillae
The pharynx is made of what?
stratified squamous epithelium & a ring of lymphoid tissue
What is the lymphoid tissue made of?
Pallitine, lingual, tubual & pharyngeal (adenoids) tonsils
What is the oesophagus made of?
stratified squamous epithelium
Describe the muscle transition of the oesophagus
upper third - skeletal (voluntary)
middle third - transition skeletal & smooth
lower third - smooth muscle
What is the distinct aspect of the oesophagus?
GLANDS IN THE SUBMUCOSA
What do the oesophageal glands do?
excrete mucous to lubricate the oesophagus
What represents the junction between the oesophagus and the stomach?
At the gastro-oesophageal what is the cell change?
stratified squamous - simple columnar
In addition to simple columnar what can be found in the stomach?
gastric pits & gastric glands
What is a gastric gland made of?
- isthmus (parietal & stem cells)
- neck (parietal & mucosa)
- fundus base (chief cells)
State the function of chief & parietal cells
chief - secrete enzymes
parietal - secrete hydrochloric acid
What separates the stomach and the small intestine?
gastro-duodenal junction containing the pyloric sphincter
Describe the structure of the small intestine
villi & crypts of lieberkuhn
Describe the duodenum
Brunner's glands - release alkaline mucous to neutralise chyme
Describe the jejunum
tall villi on plicae circularis
Describe the ileum
short villi & lots of lymphoid tissue (GALT) which forms peyer's patches
State five cells found in the small intestine
- enterocytes - absorptive
- goblet cells - produces mucin
- Paneth cells - defence
- enteroendocrine cells - produce hormones
- stem cells - replenish epithelium
What is the large intestine made of?
Colonic epithelium which contains abortive and goblet cells arranged in crypts
What is the function of the absorptive cells?
Remove salt and water