Lecture 1

Question 1

What is the purpose of salivary glands?

Answer 1

• produce saliva
• secretes saliva into the oral cavity

Question 2

What are salivary glands covered by and divided into? What is it made of?

Answer 2

• capsule and lobules
• connective tissue

Question 3

How many salivary glands are there? What are they?

Answer 3

• 3
• Parotid, Sublingual, Submandibular

Question 4

What type of cell lies deep to the basement membrane but superficial to the epithelium cells?

Answer 4

Myoepithelial cells

Question 5

How many secreting units do acini have and what are they?

Answer 5

• 3
• Mucous, Serous, Mixed

Question 6

What are the features of mucous acini cells?

Answer 6

• Oval shaped, large lumen
• Lined by columnar cells
• Flattened nucleus at basement membrane
• Contains large secretory granules of micinogen near the apex (in fresh condition- not present after staining)

Question 7

What salivary gland contains majority of mucous acini?

Answer 7

Sublingual Gland

Question 8

What are the features of serous acini cells?

Answer 8

• Spherical, smaller than mucous acinus
• Small lumen
• Lined by columnar/pyramidal cells
• Round nucleus at the basal part of the cell
• Alpha-amylase (digestive enzyme) secreted by acinar cells

Question 9

What salivary gland contains majority serous acini?

Answer 9

Parotid Gland

Question 10

What are the features of mixed acini?

Answer 10

• Spherical, smaller than mucous acinus
• Small lumen
• Lined by columnar/pyramidal cells
• Round nucleus at the basal part of the cell
• Alpha-amylase (digestive enzyme) secreted by acinar cells

Question 11

What salivary gland contains mixed acini?

Answer 11

Submandibular Gland

Question 12

How many surfaces does the tongue have and what are they?

Answer 12

• 2
• dorsal (top) and ventral (underside)

Question 13

The tongue is covvered by a mucous membrane/ mucosa… how many layers does it have and what are they?

Answer 13

• 2
• Outer epithelium and inner lamina propria/corium

Question 14

What type of epithelium is the tongue made up of?

Answer 14

1. Stratified Squamous Non Keratinized epithelium
2. Stratified Squamous Keratinized epithelium (over the papillae)

Question 15

What is the lamina propria made of?

Answer 15

• connective tissue
• blood vessels
• serous and mucous glands

Question 16

How many lingual papillae are there and what are they?

Answer 16

• 3
• Filiform, Fungiform, Circumvallate

Question 17

What are the features of filiform papillae?

Answer 17

• ⅔ of the tongue
• No taste buds
• Small conical projections covered by horny keratinized cap

Question 18

What are the features of fungiform papillae?

Answer 18

• Rounded top; narrow base
• Contains taste buds
• Present at the apex and along the lateral margins of anterior
• ⅔ of the dorsum of the tongue

Question 19

What are the features of circumvallate papillae?

Answer 19

• 8 to 12 in number
• Largest papilla, situated in a depression
• Surrounded by the circular (vallate) sulcus
• Have rounded top and narrow base
• Contain taste buds on the their lateral wall
• The sulcus receives the opening ducts of serous glands (Von Ebner’s gland)
• Serous secretion of these glands distribute the substance to be tasted & wash out the debris in the sulcus

Question 20

What are the four layers of the alimentary canal?

Answer 20

Mucosa, Submucosa, Muscularis externa, Adventitia (esophagus & duodenum)/ Serosa (rest of GI tract)

Question 21

What are the features of the mucosa?

Answer 21

Consists of:
- epithelium: simple culomnar type
- lamina propria: loose areolar CT w/ glands, lymph vessels and lymph nodules
- muscularis mucosa: inner circular, outer longitudinal layers of smooth muscle

Question 22

What are the features of the submucosa layer?

Answer 22

• irregular fibroelastic CT w/ elastic and collagen fibres
• no glands (except in esophagus)
• contains blood and lymph vessles and Meissner’s/ submucosal plexus of nerves

Question 23

What are the features of the muscularis externa layer?

Answer 23

• inner circular, outer longitudinal layers of smooth muscle
• Auerbach’s/ myenteric plexus of nerves situated between the two layers of smooth muscle

Question 24

What is the difference between the Serosa and Adventia layer?

Answer 24

Serosa: outermost layer formed by visceral peritoneum
Adventitia: outermost layer formed by CT coat (retroperitoneal)

Question 25

What type of epithelium does the esophagus contain?

Answer 25

Most of the esophagus: stratifies squamous non-keratinised epithelium Lowest part of esophagus: simple columnar epithelium

Question 26

What type of glands does the esophagus contain?

Answer 26

Mucous glands lines by stratifies columnar cells - secretes mucus which aids in the passage of food

Question 27

What type of muscle makes up different parts of the esophagus? (upper, middle, lower)

Answer 27

Upper: Skeletal Middle: Both skeletal and smooth Lower: Smooth

Question 28

How many parts of the stomach are there and what are they?

Answer 28

- 4 - Cardia, Fundus, Body, Pyloric part

Question 29

What are the longitudinal folds of mucosa on the interior of the stomach and what does it do?

Answer 29

- gastric rugae - allows for distention of the stomach to allow more space when filled

Question 30

What do the gastric pits open into on the basal end of the epithelium?

Answer 30

Cardiac glands (2-3)

Question 31

What substances does the cardiac gland secrete?

Answer 31

mucous

Question 32

What is the importance of the cardiac glands?

Answer 32

- Secretes mucous that lines the cardia which protects the esophagus from gastric reflux - part of the stomach's gastric juice

Question 33

Why is the stomachs muscularis externa layer unique to the rest of the GIT?

Answer 33

- 3 layers of smooth muscle as opposed to 2 layers - inner oblique (right side of muscularis propria), middle circular and outer longitudinal

Question 34

Gastric glands are lined by 3 types of cells. What are they?

Answer 34

- Mucous Neck cells (mucous secretion) - Parietal cells (produce HCl) - Peptic/ Cheif cells (produce pepsin)

Question 35

Which parts of the GIT does adventitia replace serosa?

Answer 35

Esophagus and Duodenum

Question 36

Nueroendocrine/ G cells are found in lamina propria in the stomach wall. What hormone does it secrete?

Answer 36

Gastrin (primarily responsible for enhancing gastric mucosal growth, gastric motility, and secretion of hydrochloric acid (HCl) into the stomach)

Question 37

what are the 3 parts of the small intestine?

Answer 37

Duodenum, Jejunum, Ileum

Question 38

The mucosa of the small intestine forms tall projections. What are they called and what is its importance?

Answer 38

- Villi - Increases surface area of the GIT wall for absorption of nutrients into the blood stream

Question 39

What are unique cells that are found in the epithelium of the small intestines and what is its function?

Answer 39

- Goblet cells - secrete mucin and create a protective mucus layer

Question 40

What are the glands in the small intestine called?

Answer 40

Intestinal glands/ crypts of Lieberkhun

Question 41

Enterocytes (intestinal cells) are lined by 4 types of cells. What are they?

Answer 41

- Goblet cells (mucin production) - Paneth cells (defensive in function) - Nueroendocrine cells (motility and secretion) - Stem cells

Question 42

How do you distinguish the duodenum from the jejunum using histology of the GIT?

Answer 42

The duodenum has brunners glands (mucous glands) located in the submucosa of the GIT wall

Question 43

How do you distinguish the jejunum from the ileum using histology of the GIT?

Answer 43

The ileum has Peyer's patches (aggregated lymphoid follicles) located in the lamina propria; sometime break the muscularis mucosa layer and extend into the submucosa

Question 44

What is a unique feature of the appendix?

Answer 44

Contains agregated lymphoid follicles in the lamina propria layer of GIT wall; may extend through the muscularis mucosa into the submucosa layer