Gastrointestinal Tract

Front 1

What are the three kinds of papillae in the tongue?

Back 1

1. Filiform Papillae
-arranged in rows on each side of the midline
-parallel to the sulcus terminalis
-high, narrow conical structures with epithelial caps - threadlike
-during illness, normal shedding of epithelial cells delayed - coated tongue
2. Fungiform papillae
-scattered singly among filiform papillae, numerous at tip of tongue
-narrow at base, expanded top - resemble a fungus
-appear red because not keratinized and blood vessels pass close to surface
-taste buds are often present on the upper surface
3. Vallate papillae
- 7 to 14 are distributed along the sulcus terminalis
- each is surrounded by a deep circular furrow
- many taste buds occur on both surfaces of the furrow
- glands of von Ebner (serous type) empty into the furrow

Front 2

What are the two cell types in taste buds?

Back 2

1. supporting cells
- lie at periphery - secrete polysaccharide material
- possess hairs (microvilli) covered by the polysaccharide secretion

2. neuroepithelial (sensory) cells
- possess apical microvilli
- sensory nerves contact base

Front 3

General layer plan of GI tract

Back 3

(1) Mucous Membrane (Mucosa)
(2) Submucosa
(3) Muscularis Externa
(4) Serosa or Adventitia

Front 4

List the sites of glands associated with the GI tract

Back 4

- glands are located in the lamina propria (part of the mucosa) and in the submucosa
- glands lie outside the GI tract and are connected to it by ducts (e.g. salivary glands, liver, pancreas)

Front 5

Name three parts of the pharynx and give the type of epithelium that lines each type

Back 5

(1) Mucous Membrane
(a) Epithelium - respiratory in nasopharynx, nonkeratinized stratified squamous in oropharynx
(b) Lamina propria - dense connective tissue with elastic layer

(2) Submocosa

(3) Muscularis externa
- inner longitudinal and outer oblique or circular layers of skeletal muscle

Front 6

Describe the muscularis externa of the esophagus at upper, middle and lower levels

Back 6

skeletal in upper third, smooth in lower third, both in middle third

Front 7

Describe rugae and gastric pits of the stomach

Back 7

irregular folds in mucosa and submucosa - appear when stomach is empty & contracted

Front 8

Give the type of epithelium that lines the stomach, name its cells and state their function

Back 8

(1) Mucosa
(a) Epithelium
(b) Lamina propria
- delicate ct fibres and usual ct cells plus lymphocytes
(c) Muscularis mucosae
helps empty glands

(2) Submucosa
- denser connective tissue containing blood and lymph vessels

(2) Muscularis externa
- 3 layers: outer longitudinal, middle circular, inner oblique

(4) Serosa
- thin layer of connective tissue covered with mesothelium

Front 9

Describe the relationship between gastric glands and gastric pits

Back 9

branched gastric glands empty into gastric pits

Front 10

List 4 ways whereby the surface area of the small intestine is increased for absorption

Back 10

(1) length of small intestine
(2) plicae circulares (valves of Kerckring)
- semicircular folds
(3) intestinal villi
- finger-like projections of epithelium
(4) microvilli
- increase surface area of epithelial cells

Front 11

Name 2 cell types in the surface epithelium of the small intestine and give their function

Back 11

(1) Columnar absorptive cells
- striated border and glycocalyx
- junctional complexes
- role in absorption and digestion
(2) Goblet cells
- apical region distended with mucigen droplets
- episodic discharge

Front 12

Give the location and function of Brunner’s glands

Back 12

In Submucosa of duodenum
- compound tubular glands, produce mucus with an alkaline, bicarbonate content
- ducts penetrate muscularis mucosae and empty into the crypts

Front 13

Describe the structure of the large intestine

Back 13

- function - absorption of water and some digestion
- Intestinal wall
- no villi
- many long, straight crypts
- surface epithelium is columnar absorptive plus many goblet cells
- Paneth cells absent
- other features similar to small intestine
- muscularis externa
- outer longitudinal layer localized into 3 longitudinal bands (taeniae coli)
- bands penetrate inner circular layer at intervals to form saccules (haustrae)
- permit distension and elongation of colon