Histology of the GI Tract

Question 1

What covers the oral cavity, oropharynx and laryngopharynx

Answer 1

Stratified squamous epithelium

Question 2

What covers the nasal cavity and the nasopharynx

Answer 2

Respiratory epithelium

Question 3

What covers the anterior 2/3rd of the tongue

Answer 3

Stratified squamous epithelium

Question 4

What covers the posterior 1/3rd of the tongue

Answer 4

Smooth stratified squamous epithelium

Question 5

Name the 4 types of papillae on the tongue

Answer 5

Fungiform
Circumvallate
Foliate
Filiform

Question 6

Describe the filiform

Answer 6

They have no taste buds

Question 7

Describe the fungiform

Answer 7

Strawberry pips - lots of taste buds

Question 8

Describe the foliate

Answer 8

Little slits, lined by taste buds- largest surface area due to the presence of slits

Question 9

Describe the circumvallate

Answer 9

Obvious growth structures - serous glands

Question 10

What 4 major layers compose the stereotypical GI tract?

Answer 10

Mucosa
Submucosa
Muscularis Externa
Serosa / Adventitia

Question 11

What are the 3 parts of the mucosa

Answer 11

Epithelium
Lamina propria
Muscularis mucosae

Question 12

What comprises the submucosa

Answer 12

Loose connective tissue

Question 13

What comprises the muscularis externa

Answer 13

Two thick layers of smooth muscle, an inner cicrular layer and an outer longitudinal layer

Question 14

What comprises the serosa or adventitia

Answer 14

Outer layer of connective tissue that either suspends the digestive tract or attaches it to other organs.

Question 15

What is the difference between serosa and adventitia

Answer 15

Serosa - something you can pick up such as the stomach.

The adventitia is something that is more bound down eg the oesophagus

Question 16

Describe the change in cells at the gastro-oesophageal junction

Answer 16

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

Question 17

What does 1 gastric pit branch into

Answer 17

1-7 gastric glands

Question 18

What are the gastric pits lined by?

Answer 18

Surface mucous cells

Question 19

What are the types of mucosa that can be found in the stomach

Answer 19

Cardia (deep gastric pits that branch into loosely packed tortuous glands)
Body (shallow gastric pits with long straight gastric glands)
Pylorus (deep gastric pits with branched, coiled gastric glands at a higher density than in the cardia

Question 20

Why is the muscularis externa of the stomach unusual?

Answer 20

It contains an additional layer - it is oblique to the usual circular and longitudinal muscle layers and is located internal to the circular layer. This layer aids the churning action of the stomach

Question 21

What is the thickened inner circular layer of smooth muscle?

Answer 21

Pyloric sphincter

Question 22

What are the pits in the small intestine called?

Answer 22

Crypts of Lieberkuhn

Question 23

Describe the length of the duodenum in terms of its different components

Answer 23

Duodenum (25cm)
Jejunum (2m)
Ileum (2.75m)

Question 24

What type of glands can be found in the duodenum

Answer 24

Brunner’s glands

Question 25

What is the name of the specialised lymphoid follicles in the ileum

Answer 25

Peyer's patches

Question 26

Where is the plicae circularis found?

Answer 26

Jejunum

Question 27

What is the function of enterocytes

Answer 27

Absorptive cell

Question 28

What is the function of Goblet cells

Answer 28

Produce mucin for protection and lubrication

Question 29

What is the function of paneth cells

Answer 29

Defensive function and a regulating role in bascterial flora

Question 30

What is the function of neuroendocrine cell

Answer 30

Produce hormones

Question 31

What is the function of stem cells

Answer 31

Divide to replenish the epithelium

Question 32

Where are fats deposited

Answer 32

In the lacteal

Question 33

How are Brunner's glands stimulated

Answer 33

With the presence of chyme

Question 34

What do Brunner's glands produce when stimulated

Answer 34

thin, alkaline, mucous to neutralise the chyme

Question 35

What do the colonic glands or the colonic crypts produce

Answer 35

Mucus

Question 36

What are the two principle types of cells in the Large intestine

Answer 36

Absorptive and goblet cells

Question 37

How are the cells in the large intestine arranged

Answer 37

In straight, tubular glands referred to as crypts that extend down the muscularis mucosae

Question 38

Describe the longitudinal smooth muscle in the large intestine

Answer 38

Not continuous | found in 3 muscular strips called teniae coli

Question 39

What is the name of the guts nervous system

Answer 39

Enteric nervous system

Question 40

Where does the ENS receive input from

Answer 40

The autonomic nervous system

Question 41

What else helps to regulate the secretion in the epithelium?

Answer 41

The second netowrk of neurones in the submucosa (submucosal plexus)