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Jason's GI Block > GI Histology > Flashcards

Flashcards in GI Histology Deck (103):
1

2 less known functions of GI:

Secretion and Protection

2

5 main functions of GI?

Digestion
Absorption
Secretion
Movement
Protection

3

4 common structural features of GIT? and 2 'other' features

mucosa
Submucosa
Muscularis externa
serosa/adventitia

Neurons
Immune cells

4

Which GIT structural layer is most diverse in cells?

mucosa

5

What are the 3 layers within the GIT Mucosa?

Epithelium
Lamina Propria
muscularis mucosae

6

How often are mucosal epithelium renewed? How?

every 5-6 days via local stem cells

7

Types of mucosal epithelium cells are usually?

columnar (enterocytes)
stratified squamous
endocrine

8

What is contained in the lamina propria of GIT mucosa? 4 things.

CT
nerves
small blood vessels
immune cells

9

What is the muscularis mucosae do?

thin layer of muscle marks the mucosal layer boundary, used for mixing

10

What kind of cells are usually barrier and found in esophagus/anal canal?

stratified squamous

11

What kind of cells are usually secretory in GIT? where predominantly?

stomach, gastric glands
large intestine: tubular glands

12

What kind of cells are usually absorptive? where?

small intestine. columnar epithelium

13

What's the purpose of the submucosa connective tissue?

strength and elasticity

14

describe the submucosa connective tissue

dense, irregular

15

Can you see small ganglia in the submucosa usually?

Hard to see without special stains

16

Are there glands and immune cells, blood vessels in submucosa?

yes.

17

Which is stronger: muscularis externa? muscularis mucosae?

muscularis externa

18

how many layers usually for muscularis externa?

2

19

what are the two layers of muscularis externa? what do they do?

inner circumferential (narrowing)
outer longitudinal (sqeezing)

20

what and where are the ganglia called within the muscularis externa?

myenteric ganglia found between inner and outer layer

21

What does GI serosa do? what kind of cells? why?

secretes fluid
simple squamous
allows organ movement

22

is there adventitia along the entire GIT? where? purpose?

Nope. in parts of esophagus and rectum
CT to join with surrounding structures

23

ENS is part of which system?

autonomic nervous system

24

What does ENS regulate?

Absorption secretion
smooth muscle activity

25

What does myenteric ganglia regulate?

smooth muscle activity

26

What does submucous ganglia regulate?

absorption, secretion

27

What kind of nerves are found in the ENS ganglia?

sensory
motor
interneurons

28

swallowing reflex does what?

propulsion of bolus

29

what kind of epithelium in esophagus?

non-keratinised squamous

30

two muscle types in esophagus? where? how controlled?

Top: striated (voluntary)
Bottom: Smooth (involuntary)

31

What kind of change between esophagus and stomach?

abrupt functional change in epithelium: squamous to glands

32

describe the 3rd external muscle of the stomach:

oblique layer, varies

33

4 kinds of cells you can find in a gastric gland? What do they secrete?

Mucous cells
Parietal cells (HCl)
Chief (pepsinogen)
Enteroendocrine (gastrin Hormone)

34

Small intestine absorbs ___% of digestion products?

85%

35

Are there immune cells in the small intestine?

yes

36

Name the surface area increasing structures of the small intestine:

plica circulares
villi
microvilli

37

What are the spaces between villi called? purpose?

crypt of Lieberkuhn
secrete fluid and mucus

38

Why have muscularis mucosae in the small intestine?

moves villi to improve mixing of contents

39

where does the lamina propria of the small intestine go?

CT extends into core of each villus

40

What is found in the lamina propria of the small intestine?

muscularis mucosae
blood, lymph vessels
immune cells

41

What are the clear cells seen on the villi?

goblet cells

42

What are Paneth cells for? where are they?

secrete antimicrobial peptides
found deep in glands

43

THE distinctive histological feature of the duodenum?

Brunner's Glands

44

Describe Brunner's Glands, where and purpose?

Highly Coiled
in Submucosa
release alkaline mucus to protect

45

How are the plica circulares and the villi in the duodenum?

low plica circulares
long villi

46

What are Peyer's patches? where are they found?

ileum
aggregates of lymphoid follicles

47

Describe the villi and amount of goblet cells in the ileum

short villi
lots of goblet cells

48

describe Muscularis externa in large intestine.

3 bundles called taeniae coli

49

3 regions of large intestine?

colon
rectum
anal canal

50

immune cells in large intestine?

yes

51

area with most goblet cells in colon
rectum
anal canal?

rectum

52

Large intestine mucosa have villi?

Nope

53

describe glands of Large intestine mucosa, what kind of cells?

straight tubular
columnar epithelium

54

More goblet cells in large or small intestine?

large intestine

55

Describe rectum to anal mucosa transitional zone.

abrupt again
glandular to squamous stratified

56

what is the largest solid gland in the body?

liver

57

6 primary functions of liver

glucose regulation (glycogen)
lipid metabolism (cholesterol)
absorption of fats into bile
protein synthesis
storage of iron/vitamins
detoxification

58

liver is 80% what?

hepatocytes

59

what are sinusoids?

specialized liver capillaries

60

what kind of CT in liver?

reticular fibres of Type 1 and III collagen

61

what do the following the hepatocyte do?
the rough ER/golgi
smooth ER

Rough: protein synthesis
Smooth: fat/steroid metabolism

62

how many nuclei and mitochondria in hepatocytes?

two nuclei
many mitochondria

63

lifespan of a hepatocyte?

150 days

64

if liver has extensive damage, how is the regeneration?

not same lobular structure, more fibrous

65

can live regenerate from damage from alcohol/hepatitis?

if severe, then no

66

how are hepatocytes organized in the liver?

in lobules around blood vessels

67

what are the 2 blood supplies to the liver?

arterial
hepatic portal system:75%

68

what is the portal 'triad'. 4 things.

hepatic artery
hepatic portal vein
bile duct
lymphatics

69

what kind of cells are the bile duct epithelium made of? vs. arterial epithelium?

columnar
squamous

70

smooth muscle in the central veins of the liver?

not much

71

what converge on the central vein in the liver? then where does it go?

sinusoids to hepatic vein > IVC

72

what give rise to sinusoids?

vein and artery

73

blood in sinusoids flow where in relation to the lobule?

towards the middle of lobule

74

what kind of blood is in sinusoids?

mixture
20% oxygenated
80% deoxygenated

75

describe the sinusoids' size?

larger than normal capillaries

76

special features of sinusoids?

discontinuous lining
gaps between hepatocytes
microvilli
kupfer cells

77

what are kupfer cells?

macrophages on inner walls of sinusoids

78

what is the gap between endothelium and adjacent hepatocyte in sinusoids called?

space of Disse

79

what is the space of Disse for?

easier to transfer certain nutrients

80

3 models of hepatocyte organization. they are? what are each of their foci?

1. Classic centres around central vein. Focus: BLOOD flow
2. Portal. Veins in periphery. focus on BILE.
3. Acinar. Focus: physiological oxygenation.

81

what is the surfactant produced in the liver called?

bile salts

82

where is bile synthesized from?

cholesterol

83

what are the bile collection channels called?

canaliculi

84

what is the direction of flow for bile?

outwards to be collected in bile duct within triad

85

focus of acinar lobule model?

physiological: O2 saturation/metabolic function

86

portal lobule model focus?

bile flow

87

what lobule model focuses on blood flow?

classic lobule model

88

what does the gall bladder do to the bile?

remove water and salts to concentrate it

89

what controls release of bile into duodenum?

sphincter of Oddi

90

what does classic lobule model focus on?

Blood Flow

91

Bile flow focus model of lobules called?

Portal lobule model

92

what lobule model focuses on physiological [O2] and metabolic function?

Acinar Model

93

What hormone controls bile secretion?

CCK from fat stim

94

what kind of cells in gall bladder epithelium?

simple columnar

95

what is the exocrine function of the pancreas?

create proenzymes/bicarbonate to be released into duodenum

96

2 areas of pancreatic exocrine cells are? colours on H&E?

basal: purple
Lumenal: pink

97

What does the basal and lumenal region of pancreatic exocrine cells each do?

basal: rough ER - protein synthesis
lumenal: zymogen granules

98

which part of the pancreatic exocrine cells faces inward towards the central duct?

lumenal side

99

what is a acini?

balls of cells with a central duct

100

what % of pancreas is endocrine?

1-2% of total pancreas volume

101

about how many islets of langerhans are in the pancreas?

around 1 million

102

what do islets of langerhans make?

insulin
glucagon

103

how is the vascular supply to the islets of langerhans?

rich