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Flashcards in GI tract Deck (29)
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1

what are the 3 types of oral mucosa?

-lining mucosa
-masticatory mucosa
-specialized mucosa

2

what does oral mucosa consist of?

1. Stratified squamous epithelium.
2. Lamina propria of dense connective tissue
3. Submucosa of loose connective tissue

3

where is masticatory mucosa found?

covering the hard palate and the gingiva (gums around the teeth). The epithelium here is keratinized or parakeratinized

4

where is lining mucosa found?

Inside of the lips, lining the buccal surfaces, covering the soft palate and lining the floor of the mouth and the inferior surface of the tongue. The epithelium here is not keratinized

5

what is the epithelium of the tongue?

Anterior 2/3: Stratified squamous epithelium, thin on ventral surface, thick and with papillae on the dorsal surface.

Posterior 1/3: Covered by smooth stratified squamous epithelium which, except for the circumvallate papillae, lacks papillae but does have substantial lymphoid aggregates in the submucosa

6

what covers the dorsal surface of the tongue?

keratinized stratified squamous epithelium with a dense irregular connective tissue lamina propria that ties the epithelium to the underlying muscle

7

what are the 4 types of tongue papillae?

-Filiform
-fungiform
-foliate
-circumvallate

8

what are the muscles in the tongue?

-extrinsic skeletal muscles
-intrinsic skeletal muscles bundles in longitudinal, transverse and vertical planes

9

what is covered by stratified squamous epithelium which is generally not keratinized?

Oral cavity, oropharynx and laryngopharynx

10

what covers the nasal cavity and nasopharynx?

respiratory epithelium

11

what are the 4 major layers (starting from the lumen and going out) that make up the digestive tract from the oesophagus to the anal canal?

1. Mucosa: 3 parts
2. Submucosa: loose connective tissue
3. Muscularis Externa: two thick layers of smooth muscle, an inner circular layer and an outer longitudinal layer
4. Serosa or Adventitia: outer layer of connective tissue that either suspends the digestive tract or attaches it to other organs

12

what are the 3 parts of the mucosa?

a. Epithelium: sits on a basal lamina
b. Lamina Propria: loose connective tissue
c. Muscularis Mucosae: thin layer of smooth muscle

13

what is the gastro-oesophageal junction?

Abrupt transition from stratified squamous epithelium of oesophagus to the simple columnar epithelium of the cardia of the stomach

14

what lines gastric pits?

mucous cells

15

what is a chief cell?

digestive enzyme secreting cell

16

what is parietal cell?

hydrochloric acid producing. cell

17

what aids the churning action of the stomach?

The muscular external layer is oblique to the usual circular and longitudinal muscle layers and is located internal to the circular layer

18

what is the gastroduodenal junction?

There is an abrupt transition from stomach mucosa to duodenal mucosa. The inner, circular layer of smooth muscle is markedly thickened to form the pyloric sphincter

19

what are the cells of the small intestinal epithelium?

-enterocytes
-goblet cells
-paneth cells
- Neuroendocrine cells
-Stem cells

20

what does the duodenum do?

receives the acidic, partly digested semifluid material called chyme from the stomach

21

what happens when Brunner glands are stimulated?

stimulated by the presence of chyme they produce a thin, alkaline mucous to neutralise the chyme

22

what are the 3 regions of the small intestine ?

Duodenum: Contains Brunner’s glands in the submucosa.

Jejunum: Tallest villi, located on permanent circular folds of the mucosa and submucosa, the plicae circularis. Lymphoid follicles infrequent.

Ileum: Characterized by shorter villi and aggregations of lymphoid follicles called Peyer’s patches found in the submucosa and often extending into the lamina propria

23

what are the two principal cell types of the large intestinal epithelium?

Absorptive cells: For removal of salts and thereby water

Goblet cells: For the secretion of mucus to lubricate the colon

24

what is the rectoanal junctions?

There is a distinct junction between the mucosa of the rectum and the non-keratinized stratified squamous epithelium of the anal canal

25

what is the nervous system of the digestive tract called?

enteric nervous system

26

Describe the enteric nervous system.

This interconnected network of fibres has two plexuses, one in the submucosa (submucosal) and one between the muscle layers of the muscularis externa (myenteric)

27

what plexus controls gut motility?

myenteric plexus

28

what plexus controls the muscle of the muscles mucosae and also helps regulate secretion in the epithelium?

submucosal plexus

29

what are the variations in mucosa?

-Protective: non-keratinized stratified squamous epithelium
-Secretory: simple columnar epithelium with extensive tubular glands
-Absorptive: simple columnar epithelium with villi & tubular glands
-Protective & absorptive: simple columnar epithelium with tubular glands