Gastrointestinal system

Question 1

Components of gastorintestinal tract

Answer 1

oral cavity, pharynx, esophagus, stomach, large and small intestine

Question 2

What are the accessory digestive organs?

Answer 2

Salivary glands

teeth

tounge

liver

gallbladder

pancreas

Question 3

masticatory mucosa and its types of epithelium

Answer 3

are the gums an hard palate

composed of parakeratinized / keratinized stratified squamous epithelium

Question 4

Lining mucosa and its epithelium

Answer 4

found on the lips, cheeks, alveolar, floor of mouth, inferior surface of tongue, and soft palate

composed of nonkeratinized/parakeratinized stratified squamous epithelium

Question 5

where is specialized mucosa found?

Answer 5

dorsal surface of tongue

Question 6

Minor salivary glands

Answer 6

lingual

labial

buccal

molar

palatine

Question 7

Major salivary glands

Answer 7

parotid

submandibular

sublingual

Question 8

function of serous cells

Answer 8

protein secretion

Question 9

function of mucous cells

Answer 9

secrete mucin

Question 10

function of intercalated duct cells

Answer 10

secrete HCO₃-

absorb Cl-

Question 11

Funtion of striated duct cells

Answer 11

Secrete K+ and HCO₃^-

absorb Na+

Question 12

Parotid salivary histology

Answer 12

will contain excretory duct and adipose cells

Question 13

submandibular salivary gland histology

Answer 13

contains ducts, serous cells, and mucous cells

Question 14

What is the structural organization of the gastrointestinal tract (alimentary canal)?

Answer 14

Layers :

Mucosa

Lining epithelium

Lamina propria

Muscularis mucosae

Submucosa

Dense irregular connective tissue with vessels (blood, lymph),nerve plexus, etc.

Muscularis externa

Inner circular layer

Outer longitudinal layer

Serosa or adventitia

Question 15

characteristics of esophagus histology

Answer 15

mucosa

submucosa

musularis externa

adventitia

Question 16

what type of epithelium is found in the stomach?

Answer 16

simple columnar epithelium

Question 17

Histological regions in the stomach

Answer 17

Cardia –

cardia glands produce primarily mucus

Body/Fundus –

gastric/fundic glands produce HCl and enzymes

Pylorus –

pyloric glands produce primarily mucus

Question 18

Structure of Gastric/fundic glands

Answer 18

• Simple, branched tubular gland
• Present throughout stomach (except where cardiac and pyloric glands are)

3 regions:

Isthmus (stem cell niche)

Neck

Fundus

Question 19

function of gastric/fundic glands

Answer 19

they produce 2L of gastric fluid a day

Fluid consists of:

• HCL
• Pepsin
• Mucus
• Intrinsic factor
• Gastrin

Question 20

Types of cells in gastric/fundic glands

Answer 20

Mucous cells

Chief cells

Parietal cells

Enteroendocrine cells

Stem cells

Question 21

The 2 types of mucous cells and their functions

Answer 21

Surface mucous cell:

Columnar cell

Produces/secretes mucinogen (stains with PAS)

mucus is thick, viscous, gel-like (cloudy)

high concentration of bicarbonate and potassium

Mucous neck cell:

Lines gastric pits

Produces/secretes soluble mucous (i.e. clear), less mucinogen than surface mucous cell

Secretion stimulated by vagus nerve

Question 22

Characteristics of chief cells

Answer 22

Protein secreting (enzymes, especially pepsinogen)

Has abundant rER

Found in deep part of gland

Question 23

characteristics of parietal (oxyntic) cell

Answer 23

Produce HCl and intrinsic factor

HCl secretion activated by gastrin, histamine, & acetylcholine

Intracellular canalicular system continuous with gland lumen Numerous microvilli

Large cells that stain with eosin (acidic dyes)

Located in neck and deep part of gland

Question 24

characteristics of enteroendocrine cell

Answer 24

‘Open’ and ‘Closed’ cells

Secrete into the lamina propria or vasculature (not into gastric lumen)

Chemoreceptors (‘Open’ cells)

Question 25

components of the small intestine

Answer 25

Duodenum Jejunum Ileum

Question 26

what is the function of the small intestine and what are the structures that aid in the function?

Answer 26

Digestion and Absorption!!! **Aided by**: Plicae circulares (circular folds) Villi Microvilli

Question 27

cells found in the epithelium of the small intestine

Answer 27

* Enterocytes * Goblet cells * Paneth cells * Enteroendocrine cells * M cells (microfold cells)

Question 28

characteristics of enterocytes

Answer 28

intestinal absorptive columnar cells that secrete glycoprotein enzymes intp apical plasma membrane These cell have features such as * Microvilli * Terminal web (contractile microfilaments in apical cytoplasm, attach to zonula adherens) * Tight junctions * Lateral plications (elaborate, flattened cytoplasmic processes)

Question 29

characteristics of goblet cells

Answer 29

Produce mucus Periodic Acid Schiff stains contents

Question 30

characteristics if paneth cells

Answer 30

* Regulate normal bacteria flora in small intestine by secreting α-defensins (antibacterial lysozyme) that digests cell wall of some bacteria * Located at the base of intestinal glands * Strong eosin stain

Question 31

Characteristics of Intestinal glands a.k.a. Crypts of Lieberkuhn

Answer 31

Simple columnar epithelium Tubular structures that open at the base of villi Contain immune cells, including Paneth cells Major component of GALT (Gut-associated lymphoid tissue)

Question 32

Characteristics of M cells

Answer 32

M cells are the epithelial cells that overlie Peyer's patches (lymphatic nodules) Has microfolds on apical surface **Function :** * 'Antigen transporting cell’ * Endocytose microorganisms (and macromolecules) from intestinal lumen, exocytose near T lymphocytes

Question 33

characteristic of Peyer's patches

Answer 33

composed of aggregates of lymphatic nodules within lamina propriaand submucosa Component of GALT (gut-associated lymphatic tissue) Prominent in ileum

Question 34

Characterisitcs of Brunner’s (submucosa) glands

Answer 34

Glands are present in the submucosa of the duodenum Secrete enzymes and mucous Secretions are pH 8.1-9.3 (alkaline glycoproteins and bicarbonate)

Question 35

histology of cecum and appendix

Question 36

Key features of the outer surface of the large intestine/colon

Answer 36

**Teniae coli** thickened bands of outer muscular layer **Haustra coli** sacculations between teniae coli **Omental appendices** fatty serosa projections

Question 37

function of the large intestine/colon

Answer 37

Absorption of electrolytes and water elimination of waste

Question 38

what are the cells of the large intestine?

Answer 38

Intestinal Glands Columnar absorptive cells (Enterocytes) Goblet cells (more numerous than in small intestine) Enteroendocrine cells Lymphatic nodules

Question 39

histology of the rectum

Answer 39