Lecture 13- Digestive Tract Flashcards Preview

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Flashcards in Lecture 13- Digestive Tract Deck (75)
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31

What type of cells are the surface mucous cells?

Simple columnar epithelial cells

32

Why don't gastric contents normally injure the stomach mucosa?

Stomach mucosa is covered with mucus and bicarbonate that will neutralize acid

33

What happens at the apical cup of mucinogen granules?

Mucus and bicarbonate are secreted

34

What is the pH at the surface of mucosa and inside the stomach?

- Mucosa pH=7
- Stomach pH= 1

35

What affect can aspirin have on the stomach?

It can deteriorate the surface mucosa leading to stomach ulcers.

36

What are the for anatomical regions of the stomach?

1) cardia
2) fundus
3) body
4) pylorus

37

What are the three histological regions of the stomach?

1) cardiac
2) fundus/body
3) pyloric
* differences in mucosa

38

Describe the cardiac region of the stomach

- simple columnar epithelium
- cardiac glands present that secrete mucus

39

What types of glands are present in the fundus/body?

Gastric glands

40

What are the three parts of gastric glands and how does their size compare to cardiac glands?

- isthmus
- neck
- base
-much larger than cardiac glands

41

What do surface mucus cells in gastric pit secrete?

Alkaline mucous and bicarbonate

42

What do mucous neck cells secrete?

more neutral mucous

43

What do parietal cells in the isthmus/neck secrete?

HCl and intrinsic factor

44

What do chief cells in the base secrete?

Pepsinogen and gastric lipase

45

How do parietal cells secrete acid?

They use a Hydrogen-Potassium ATPase pump

46

What organelles have proton pumps in parietal cells?

-Tubulovesicles
- Canaliculi with microvilli

47

What is the role of mitochondria in the parietal cells?

- Lots of ATP is needed to run the proton pump

48

What happens when food is digested?

Tubulovesicles with the proton pump fuse with the canaliculi membrane

49

Why is there acid in the stomach? (3)

- helps kill bacteria
- acid and intrinsic factor important for Vitamin B12 absorption
- acid converts pepsinogen to pepsin

50

Where are the pyloric glands found?

The pylorous

51

What types of cells are found in the plylorous?

- surface mucous cells
- mucous neck cells
- G cells
- Enteroendocrine cells

52

What are the distinct features of pyloric glands?

- deeper pits
- shorter coiled pyloric glands

53

What stimulates the release of gastrin?

Stomach distention

54

What do enterochromaffin-like cells do?

Release histamine that releases acid

55

What cells bind to enterochromaffin-like cells?

Gastrin and ACh from parasympathetic response

56

Blocking the secretions of what kinds of cells would potentially treat gastroesophageal reflux disease?

- G cells (gastrin)
- Parietal cells (acid)
- enterochromaffin-like cells (histamine)

57

What makes up the pyloric sphincter?

- Smooth muscles thickening the middle layers of the stomach muscularis

58

Do the circular folds of the small intestine change shape during digestion?

No

59

What is the main role of the small intestine?

Absorb nutrients and minerals from food

60

What types of cells are found inside the lamina propria of the small intestine?

Lymphocytes