9/24 Histology of digestive system Flashcards Preview

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Flashcards in 9/24 Histology of digestive system Deck (109):
1

what is the general type of epithelium in the oral cavity?

stratified squamous: both deratinized (ortho and para) and non-keratininzed

2

what is the embriological origin of the oral cavity

derived from ectoderm, like skin, not endoderm like the rest of the gut

3

what is the average turn over of the stratified squamous of the oral cavity

1-2 weeks

4

the underlying connective tissue

lamina propria

5

How and why is there a large immune pressence in the oral cavity

many lymphocytes and the tonsils, 3X10^9 PMNs enter lamina propria everyday, and small mixeed sero/mucous salivary glands. all to take care of small immune responses to the large number of pathogens in the mouth

6

what covers the back of the toungue

lymphatic tissue, and the palatine tonsil

7

the structure near the back of the tounge wear most taste happens

circumvallate papilla

8

the structures on the majority of the dorsal surface of the toungue that taste

fungiform papilla

9

the structures of the dorsal of the tounge that cover most of the surface

filiform papilla

10

The layers of the tounge in the microscope

stratisfied epithelium; loose or dense connective tissue (lamina prpria) then striated skeletal muscle and adipose tissue

11

why do you have skeletal muscle tissue in the tounge

moves food back, and requeired for normal speech. arranged in all kinds of orientations

12

The most common form of cell on the dorsal surface of the tounge

filiform papillae

13

the moat that surrounds the circumvallate papillae

crypt

14

why does the circumvallate papillae have crypt

has glandular structures to wash material out to allow constant tasting of new things

15

the glands that wash out the crypt

Von Ebner's gland: serous glands, they appear as globular structure in the connective tissue with ducts associated with the crypt

16

what is the purpose of saliva

lubricate the mouth w/mucous secretion. amylase in serous secretion (digest carbs). Helps prevent infection!

17

purpose of the salivary glands

Make saliva; get infected (mumps, and impacted ducts); growth factors; make haptocorrin.

18

how does salive act as defensive agent?

secrete lactoferrin (iron binding protien against bacteria), lysozyme (desolve bacteria cell walls), and defensins (anti-biotic protiens) and transport IgA (binds to pathogens)

19

what is haptocorrin?

a vitamin B12 binding protein

20

why would the saliva produce growth factors?

maybe to promote wound healing in the mouth and in other parts of the body when you lick wounds

21

cells that secrete in a serous fashion and are a spherical gland

Serous acinus

22

Glands that produce mucous

mucous tubule

23

combinded serous and mucous cells in a singe duct

mucous tubule and serous demilune

24

the course of mucous and serous once produced form serous acinus/demilune and mucous tubule

glands connected to intercalated ducts, striated ducts, and interlobular ducts

25

what ducts are found in the parenchyma of the secretory units

the glands and the intercalated ducts and striated ducts are in the parenchyma of the glands

26

the section of the duct that is in the stroma

the interlobular ducts

27

ducts in the stroma or connective tissue

interlobular ducts

28

what do the smooth muscle aorudn the interlobular duct do

Myoepithelial cells contract to push out saliva

29

what type of cells are the intercalated ducts

cuboidal cells

30

type of cells in striated duct

colomnar

31

describe the histological appearence of the serous secreting cells (serous demilune)

they are in a semi-circle of dark staining cells with prominate nucleus connected to a light stained area of duct

32

describe the histological appearance of the mucous secreting cells

they are light staining cells along the ducts with no clear nucleus

33

need special staining of anti-myosin to see well

the myoepithelial cells that squeez out the spit

34

describe the intercalated duct

cuboidal

35

describe the striated ducts

colomnar cells

36

how does striated duct cells control hemiostasis

recover sodium and chloride from the saliva, but don't really recover much water, use a Na,K-ATPase to pump

37

histology of the interlobular ducts

may even be stratified columnar, surrounded by dense irregular connective tissue.

38

what is the general plan of the gut?

4 layers!

39

what are the 4 layers of the general plan of the gut?

Mucosa; Submucosa; Muscularis externa; Serosa (adventitia)

40

what are the layers of the mucosa?

the epithelium, lamina propria, musclaris mucosae

41

what are the sublayers of the muscularis externa?

circular muscle, myenteric plexus (nerves); longitudinal muscle

42

how does the mucosa change from the stomach to the intestine to the colon?

stomach has no villus, but has pits, intestine has villus, colon has no villi and no pits.

43

describe the mucosa layer of the gut

epithelium, lamina propria is hard to see, lined with muscularis mucosa at the bottom of the epithelium

44

describe the submucosa layer of the gut

dense irregular CT, large vessels; sumbucosal enteric nerve plexus (hard to see)

45

describe the muscularis externa layer of the gut

smooth muscle of 2 layers (inner circular, outher longitudinal); enteric plexus beween muscle layers (control motility)

46

describe the serosa or adventitia layer of the gut

connective tissue, when covered with mesothelium its a serosa, retroperitoneal organs can have both.

47

Unique Esophagus component in the submucosa

Esophageal glands

48

what is the purpose of esophageal glands?

add secretions that help food slide down the tube, and make the esophagus look different from the vagina tissue!

49

why is the fourth layer in the esophagus adventitia and not serosa

it doesn't have a layer of mesothelium

50

what is the muscle in the esophagus?

at the top it is striated skeletal muscle and then it blends into smooth muscle and at the bottom it is just smooth muscle in the lower third

51

how do we know that the muscle in the upper 1/3 of esophagus is striated skeletal

large cells of muscle with nucleus on the outside

52

what are the functional muscles that contract or relax to alow food to pass?

the upper and lower esophageal sphincters.

53

how is the lower esophageal sphincter controlled?

it is a smooth muscle sphincter, that is tonically contracted and must be relaxes for material to enter the stomach

54

what are the characteristic structure seen in the epithelium of the stomach

Pits, necks (start of glands), glands, base (end of glands)

55

describe the junction of the esophagus/stomach

very sudden switch form stratisfied to simple colomnar

56

what causes heartburn?

lower esophageal sphincter fails to keep stomach acid out of the esophagus, causing pain.

57

what happens if common heart burn damages the epithelium

esophagitis

58

when chronic esophagitis

Gastro-Esophageal Reflux Disease or GERD

59

increased risk of dysplasia and esophageal cancer

chronic GERD, and barrett esophagus!

60

how is the barratt epithelium different?

it is red due to a lack of the stratisfied layers (now simple!)
replacement of stratified squamous non-keratinized epithelium by mostly simple colomnar epithelium with lots of goblet cells (looks like colon)

61

what is the general path to esophageal cancer?

Chronic inflammation; Mataplasia; balance of tumor suppressors and promoters

62

newer model of the development of barret's esophagus...

residual embryonic cells invade and migrate up the esophagus after acid reflux lead to metaplasia of colon like cells.

63

what are the four anatomical regions of the stomach

cardia; fundus; body; pylorus

64

what are the three histological divisions of the stomach

the cardia; the body/fundus; and the pylorus cells

65

how do we tell the difference between cardia/body/pylorus cells in the stomach

cardia: pit and glands have about the same length;
Body: pit is a bit shorter than the glands
Pylorus: pit is much longer than the glands

66

what do you often see where there is a transition between different epithelial layers

lymphatic agrigates (blobs of dark staining cells)

67

what does the light staining fo the cardia glands tell us

they are producing mostly mucus

68

what are the light and dark colored cells in the body and fundus of the stomach located just below the glands in the epithelium

the parietal and chief cells!

69

how is the stem cell unusual in the stomach?

the stem cells are found in the top of the glands! maybe to replace the very short lived pit cells above them?

70

what are the three regions of the gland in the stomach epithelium?

the isthmus, the neck, the base.

71

what is the life span of a pit cell?

about 3 days to a week

72

what is the life span of a gland cell?

week to a month

73

the body cells are also called:

Gastric epithelium

74

the cells that line the pits:

Suface mucus cells

75

the cells in the glands that are large, pale cytoplasm with central nucleaus (fried eggs!)

the Parietal cells

76

the cells that make mucus in the glands, stuck between the parietal and chief cells

the neck mucous cells;

77

the cells that are dark staining in the glandular region of the epithelium of the body of the stomach (like dark fried eggs)

Chief cells

78

hormone producing cells in the stomach

Enteroendocrine cells

79

Amine precursor uptake and decarboxylation

APUD enteroendocrine cells

80

what is the DNES?

the diffuse Neuroendocrine system

81

Enteroendocrine cells in the stomach produce what?

gastrin (yellow cells!), glucagon, histamine, somatostatin, serotonin and gherlin

82

stimulates hunger if not enough food in stomach

gherlin

83

stimulate parietal cells to secrete HCl

gastrin

84

Cells that produce acid

Parietal cells

85

how do parietal cells secrete acid?

through H+,K+ - ATPase

86

what stimulates the release of parietal cell acid

several agents including gastrin and histamine

87

how do the parietal cells control release of acid

they have membrane bound tubules with the proton pump that fuse with the plasma membrane to allow the release of the HCl acid

88

the only critical function of the stomach, a function of the parietal cells

gastric intrinsic factor for vitamin B12 absorption

89

what if lose GIF producing parietal cells

lose the absorption of B12 and then get pernicious anemia

90

describe the movement of acid out of parietal cells

On Lumen: ATP pump moves protons out and Cl- pore facilitate diffusion to give HCl;
On Blood vessel side: pump HCO- out and Cl- into the cell.

91

where does the H+ and the Cl- come from in the gastric parietal cell?

the Cl- is pumped in from the blood using HCO-/Cl- pump. The H+ is from CO2 and H2O forming H2CO3 using carbonic anydrase, that is carbonic acid and releases the H+

92

Control of parietal cell acid secretion

from vegus nerve, enteroendocrine cells, etc. a veriety of different controls

93

cephalic phase

when just think about or anticipate food the vegus nerve stimulates the release of acid.

94

stiumuli to produce acid include?

smell, taste, cinditioning, distension, amino acids, small peptides etc.

95

Phases of acid secretory control

Cephalic phase (see or think aobut food) Gastric phase (distension etc). Intestinal phase (inhibits when digesting food)

96

Chief cells!!

found in the bottom of the glands, secrete pepsinogen and gastric lipase

97

the other names of chief cells

peptic cells or incorrectly zymogenic cells

98

the mucus that is produced by the mucus cells is critical, why is that?

it traps bicarbonate, and provides a barrier to acid coming into the cells, provides physical barrier for the pepsin attacking the cells.

99

why would stress H. pylore, or smoking/alcohol or pharmaceuticals lead to damage of the cells in the stomach

breaks down the mucus and leads to pepsin and acid damage

100

How can we discriminate the Plexis in the muscularis externa and serosa

the nerves can be detected due to the light staining in the middle of the dark staining of the muscle

101

the enteric plexi and the vegas nerve seem to influence what kind of movement in the stomach?

Gastric movements that churn the stomach contents and then spurt out 10ml of contents or so into the duodenum

102

what are the 2 basic patterns of GI motility?

paristalisis or contraction of smooth muscle waves to activly move material down the length of the intestine;;; or segmental contractions that squich and release the contents and mix it up and down the intestine -- you get a balance of these two movements

103

what does the muscosal barrier protect the epithelium from

acid and proteases like pepsin both a diffusion and a chemical barrier

104

what if the mucus in broken down

ulcer

105

what if the mucus is broken and break down the muscular mucosa into the submucosal, what do you have?

peptic ulcer

106

treatment with antiacids is not as effective as other ulcer treatment such as:

antibiotic against H. pilore and anti-histimines etc.

107

gastric adenocarcinoma is dangerous, but why?

it is very asymptomatic and very difficult to detect until it has progressed.

108

Am I going to get gastric adenocarcinoma?

probably not, rare in N. America and probably because of diet and environement

109

what is the histology of adenocarcinoma

you can't decipher the different gland and epithelial cells of the pits and and mucosal layers...all the epithelial cells look the same!