Histology: GI Tract

Question 1

Examining the hard palate, what structure is found lying on top of the lamina propria?

Answer 1

The stratified squamous epithelium

Question 2

What is the connective tissue of the lamina propria composed of?

Answer 2

1. regular connective tissue
2. thick collagen bundles
3. nerves
4. blood vessels

Question 3

What thin structure makes the stratified squamous epithelium in the hard palate keratinised?

Answer 3

The thin stratum corneum.

Question 4

Why is the mucosa lining the hard palate known as the masticatory mucosa?

Answer 4

As food is pressed against the hard palate during chewing to form a bolus for swallowing.

Question 5

Name the type of mucosa that lines the buccal surfaces.

Is this type of mucosa keratinised or non-keratinised?

Answer 5

This mucosa is known as lining mucosa.

Lining mucosa is non keratinised.

Question 6

What is the name of the outer surface of the tongue?

Answer 6

The dorsal surface

Question 7

What type of papillae give the dorsum of tongue a rough surface?

Answer 7

Filiform papillae

Question 8

What type of papillae resemble the appearance of strawberry pips?

Answer 8

Fungiform papillae

Question 9

Examining the layers of the tongue, what exists between the epithelium and underlying muscle?

Answer 9

a lamina propria of dense irregular connective tissue

Question 10

Looking at the ventral surfaces of the tongue, state whether these surfaces are keratinised or non-keratinised.

Answer 10

the ventral surfaces are NON-KERATINISED.

Question 11

Where are the nuclei found within the tongue?

Answer 11

There are nuclei present all the way to the surface of the tongue.

Question 12

What colour do the minor salivary glands appear under the virtual microscope?

Answer 12

More purple and more grainy than the surrounding red muscle.

Question 13

What do the deep furrows on the left margin of the tongue represent?

Answer 13

Foliate papillae

Question 14

What line these furrows?

Answer 14

Taste buds

Question 15

Name the four types of lingual papillae?

Answer 15

Filiform
Foliate
Fungiform
Circumvalliate

Question 16

Name the only type of lingual papillae that isn’t involved in taste?

Answer 16

Filiform papillae are the only type of papillae not involved in taste.

Question 17

The digestive tract from the oesophagus to the rectum consists of 4 basic layers. What are these layers?

Answer 17

1. The mucosa: which itself is divided into;
   (a) epithelium
   (b) lamina propria
   (c) muscularis mucosae
2. The submucosa
3. The muscularis externa
   (also refereed to as the muscularis propria)
4. The adventitia or serosa

Question 18

What are gastric pits of the stomach lined with?

Answer 18

Surface mucous cells

Question 19

What are the gastric glands responsible for?

Answer 19

Emptying into the base of the gastric pits

Question 20

Name the 5 cells of the gastric gland and their functions.

Answer 20

1. Surface mucous cells: secrete protective mucous
2. Parietal cells: produce hydrochloric acid
3. Chief cells: secrete pepsinogen
4. Stem cells: replace all cell types via division
5. Enteroendocrine cells: hormone secreting cells that provide control functions.

Question 21

Are the cells of the gastric gland evenly distributed?

Answer 21

No

Question 22

What cells mostly make up the isthmus of the gastric gland?

Answer 22

Parietal cells and Stem cells

Question 23

What cells mostly make up the neck of the gastric gland?

Answer 23

Neck mucous cells and parietal cells.

Question 24

What cells mostly make up the fundus (base) of the gastric gland?

Answer 24

Chief cells, with a few parietal cells and enteroendocrinecells (also called neuroendocrine cells).

Question 25

What is the function of a chief cell?

Answer 25

produce pepsinogen

Question 26

What is the function of a parietal cell?

Answer 26

Produces hydrochloric acid

Question 27

What makes the muscularis external unusual?

Answer 27

It has an additional oblique layer that aids the churning action of the stomach.

Question 28

The mucosa of the stomach contains aggregations of small purple cells. These are part of GALT. What does 'GALT' stand for?

Answer 28

Gut associated lymphoid tissue

Question 29

There are no glands in the submucosa of the stomach, however the duodenum the submucosa is packed with mucous secreting glands (called Brunner's glands) that stain magenta. What do Brunner's glands secrete and why are they only present in the duodenum?

Answer 29

When stimulated by the presence of chyme they produce a thin, alkaline mucous to neutralise the chyme. Brunner's cells are only found in the duodenum as their role is to protect the intestinal walls from gastric juices

Question 30

The small intestinal epithelium consists of two parts, what are these two parts?

Answer 30

Villi and crypts (Lieberkühn)

Question 31

What are the 3 regions of the small intestine?

Answer 31

1. Duodenum 2. Jejunum 3. Ileum

Question 32

Examining the hard palate you will notice that the interlocking projections of the epithelium and lamina propria are very long and thus highly interdigitated. Why do you think this is the case?

Answer 32

As interlocking helps to anchor the epithelium to the underlying connective tissue.

Question 33

The stratified squamous epithelium of the hard palate is keratinized. Where else in the oral cavity would you find keratinized epithelium?

Answer 33

The gingivae and much of the dorsal surface of the tongue.

Question 34

What classification of epithelium lines the oesophagus?

Answer 34

Non-keratinized stratified squamous.

Question 35

Following the path of digestive tract from the oesophagus to the rectum, which of the 6 layers would you expect not to find blood vessels?

Answer 35

Lining epithelia

Question 36

Which parts of the oesophagus have a muscularis externa composed of: a) skeletal muscle b) mixed skeletal and smooth muscle c) smooth muscle.

Answer 36

a) upper third b) middle third c) lower third

Question 37

What type of cell are the magenta cells scattered within the epithelium of the duodenum?

Answer 37

Goblet cells

Question 38

Between the circular and longitudinal layers of the muscularis externa, you can observe pale masses of neuronal cells of the myenteric plexus (also called ‘Auerbach’s plexus’). What is the role of these cells?

Answer 38

Coordination of contraction of the muscularis externa (for peristalsis in most of the gut tube)

Question 39

What is the role of Paneth cells?

Answer 39

They produce and secrete antimicrobial compounds such as definsins

Question 40

What are the two main cell types present in the epithelium lining the surface of the colon and the colonic glands?

Answer 40

1. Absorptive cells | 2. Goblet cells