60. Oesophagus - microscopic

Question 1

How many main layers does the oesophagus wall have?

Answer 1

Four layers.

Question 2

What is the innermost layer of the oesophagus?

Answer 2

The mucosa (inside lining).

Question 3

What is the function of the mucosa?

Answer 3

To protect the oesophagus from food damage.

Question 4

What is the second layer under the mucosa?

Answer 4

The submucosa.

Question 5

What is inside the submucosa?

Answer 5

Glands and blood vessels.

Question 6

What is the third layer of the oesophagus wall?

Answer 6

The muscularis (muscle layer).

Question 7

What is the function of the muscularis layer?

Answer 7

To push food down through the oesophagus.

Question 8

What is the outermost layer of the oesophagus?

Answer 8

The adventitia (outer covering).

Question 9

What is the function of the adventitia?

Answer 9

To hold and protect the oesophagus from the outside.

Question 10

What type of epithelium lines the oesophagus mucosa?

Answer 10

Non-keratinized stratified squamous epithelium.

Question 11

Why is the oesophagus lined with stratified squamous epithelium?

Answer 11

To protect against mechanical damage from food.

Question 12

What glands are found in the submucosa?

Answer 12

Mucous glands that help lubricate the oesophagus.

Question 13

What types of muscle are found in the muscularis layer?

Answer 13

Skeletal muscle (upper third), mixed skeletal and smooth muscle (middle third), smooth muscle (lower third).

Question 14

What is the function of the oesophageal glands?

Answer 14

To secrete mucus that reduces friction and protects the lining.

Question 15

How is the oesophagus different from the rest of the GI tract in outer covering?

Answer 15

It has adventitia (not serosa) because it is in the neck and thorax, not covered by peritoneum.

Question 16

Where are lymphatic vessels mainly located in the oesophagus wall?

Answer 16

In the submucosa and adventitia.

Question 17

What nerve plexus is found in the muscularis layer?

Answer 17

The myenteric (Auerbach’s) plexus, which controls muscle contractions.

Question 18

What nerve plexus is found in the submucosa?

Answer 18

The submucosal (Meissner’s) plexus, which controls secretions and blood flow.

Question 19

What type of connective tissue is found in the submucosa?

Answer 19

Loose connective tissue with elastic fibers.

Question 20

What special feature helps the oesophagus expand during swallowing?

Answer 20

The presence of longitudinal folds in the mucosa and submucosa.

Question 21

What separates the circular and longitudinal muscle layers in the muscularis?

Answer 21

The myenteric (Auerbach’s) nerve plexus.

Question 22

What is the role of the circular muscle layer in the oesophagus?

Answer 22

It contracts to narrow the lumen and push food downward.

Question 23

What is the role of the longitudinal muscle layer in the oesophagus?

Answer 23

It shortens the oesophagus during swallowing.

Question 24

What kind of mucus do oesophageal glands secrete?

Answer 24

Neutral mucus to lubricate and protect the lining.

Question 25

Does the oesophagus have villi or crypts like the intestine?

Answer 25

No, the oesophagus has a smooth surface without villi or crypts.

Question 26

How does the epithelium change at the gastroesophageal junction?

Answer 26

It changes from stratified squamous epithelium to simple columnar epithelium (stomach lining).

Question 27

What clinical condition is related to abnormal epithelial change in the lower oesophagus?

Answer 27

Barrett’s esophagus (metaplasia from squamous to columnar epithelium).

Question 28

Why is the adventitia important in the oesophagus?

Answer 28

It anchors the oesophagus to surrounding structures in the neck and chest.

Question 29

What protects oesophagus from mechanical damage?

Answer 29

Thick stratified squamous epithelium.

Question 30

What is missing in oesophagus epithelium that makes it sensitive to acid?

Answer 30

It lacks a mucus-secreting surface layer like the stomach.

Question 31

Where is lymphoid tissue found in the oesophagus?

Answer 31

In the lamina propria and submucosa.

Question 32

What is the difference between the muscularis mucosae and muscularis externa?

Answer 32

Muscularis mucosae is a thin smooth muscle layer inside the mucosa; muscularis externa is the large muscle layer that moves food.

Question 33

How does oesophagus handle stretching when swallowing?

Answer 33

Its mucosa and submucosa form longitudinal folds that flatten as food passes.