3 - Stomach layers Flashcards

1
Q

From inner to outer, what are the layers of the GI tract?

A

Mucosa
Submucosa
External muscle
Serosa

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2
Q

What are the layers of the mucosa?

A

Epithelial - selectively permeable barrier, allows transport of food, produces hormones and mucus
Lamina propria - Lymphoid nodules and macrophages, produce IgA, resistant proteases
Muscularis mucosae - smooth muscle with different orientations, keeps epithelium in contact with gut contents and keeps crypt contents dynamic, preventing stagnation and inflammation

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3
Q

What is contained in the sub mucosa?

A

Dense connective tissue
lymph tissue
glands
blood vessels

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4
Q

What is contained in the serosa?

A

Blood vessels
Lymph vessels
Adipose tissues

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5
Q

Describe the epithelia of the gut

A

Stratified squamous in the oesophagus and distal anus - resists friction
Simple columnar everywhere else

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6
Q

Where are enterocytes found and what is their function?

A

Small intestine and colon

Brush border of microvilli to increase surface area, which aids in absorption

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7
Q

Where are goblet cells found and what is their function?

A

In between enterocytes, increasing in number from duodenum to colon
Produces mucus to protect epithelia from:
Friction (lubricates)
Chemical damage (acid)
Bacterial inflammation (forms a physical barrier)

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8
Q

Where are gastric surface mucous cells found and what is their function?

A

Line gastric mucosa and gastric pits

Secretes mucus and HCO3 that forms barrier to stomach acid

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9
Q

Where are paneth cells found and what is their function?

A

At base of crypts

Secrete antibacterial proteins to protect stem cells, secretory vesicles are red

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10
Q

How can crypts be affected by disease processes?

A

Inflammatory bowel disease:
Crypt alteration
Cryptitis (inflammation of wall)
Crypt abscess (neutrophils in lumen)

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11
Q

Where are enteroendocrine cells and where are they found?

A

Secrete hormones to control gut function

Predominantly located in crypts and gastric glands

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12
Q

Describe glandular tissue in the gut

A

Exocrine
Made up of acini - secrete serous and enzymes
and Tubules - Secrete mucous, Brunner’s gland
Connected to ducts

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13
Q

Describe how disease processes affects glandular tissue in the gut

A

Ulceration - Erodes muscularis mucosae due to failure of mucus production
Coeliac disease - Inability to tolerate gliadin, damages mucosa, leading to poor digestion and malabsorption
IBD - damages crypts

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