lect 32 & 33-Upper GI histology Flashcards Preview

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Flashcards in lect 32 & 33-Upper GI histology Deck (73):
1

what is the epithelium of the GI tract

stratified squamous at either end
simple columnar most of the length

2

what type of muscle is in the GI tract

skeletal at either end (including upper esophagus)
smooth muscle throughout most of length

3

what is the GI intrinsic rhymicity mostly due to

presence of an enteric nervous system that exists independently of external influences including ANS

4

what are the peptide neurotransmitters

bombesin
motilin
vasoactive intestinal peptide

5

what do unicellular endocrine cells secrete

secrete neuropeptides

6

what are unicellular endocrine cells derived from

endoderm

7

what are intrinsic nerve fibers derived from

neural crest

8

what does the mucus membrane of the lip consist of

stratified squamous epithelium
basement membrane
lamina propria

9

what 3 embryonic tissues interact in the development of teeth

ectoderm, neural crest and mesoderm

10

what gves rise to dental papilla

neural crest and mesoderm

11

what forms the enamel organ

ectoderm

12

what is the dental primordium formed from

basal cels of the oral ectoderm

13

what is the labiodental lamina

epithelial shelf that grows from the thickening primordial into the mesenchyme as a bifid structure

14

what is the dental lamina

internal limb (teeth)

15

what is the dental sac

CT sac surrounding the enamel organ and dental papilla and forms cementum and the periodontal membrane

16

what forms the dentin matrix through the life of the tooth

odontoblasts

17

define tomes' dentinal fibers

cytoplasmic extensions of the odontoblasts continuing through the predentin and dentinal layers to the dentin-enamel junction

18

what type of collagen in dentin primarily composed of

collagen type 1

19

what forms the enamel which covers only the tooth crown

ameloblasts

20

what is the hardest substance in the body

enamel

21

what organic components are unique to enamel and are removed after calcification

amelogenins and enamelins

22

what does pulp originate from

dental papilla containing condensed mesenchyme

23

what is the periodontal membrane

CT formed from dental sac with fibroblasts, osteoblasts, cementoblasts, collagen fibers, blood vessels and nerve vessels

24

what binds the cementum to the bony socket

periodontal membrane

25

what separates the anterior 2/3 of the upper oral portio of the tongue from the posterior 1/3

sulcus terminalis

26

what are lingual papillae formed of

central core of CT lamina propria covered by stratified squamous epithelium

27

what are the 2 types of cells of taste buds

sustantacular cells and taste cells

28

what are sustentacular cells

taste bud cells that are spindle-shaped support cells and arranged like barrel-staves to surround the inner taste pore at the base

29

what does the basal part of taste cells secrete

neurotransmitters

30

what do salt and sour taste sensations use as a signal transduction mechanism

ionic transport

31

what does sour taste sensation involve

hydrogen ion blockage of potassium ion channels to cause depolarization

32

what does bitter taste involve

gustucin (homologue of retinal transducer)
involves activates of Galpha subunit, decrease in cGMP, and closure of sodium channels and hypo polarization of the taste cells

33

what type of epithelium is in the mucosa of the digestive tube

stratified squamous transitioning to simple columnar

34

what type of tissue is in the lamina propria of the digestive tubule

loose areolar CT associated with epithelium

35

what type of tissue in in the submucosa of the digestive tube

dense, irregular CT

36

what nerve plexus is located in the submucosa of the digestive tube

meissner's plexus

37

what are the functions of muscular is externa

regulates size of lumen
regulates rhythmic movement of GI tract

38

what is tissue of the serosa of the digest tube

dense irregular CT
layer of submesothelial Ct

39

what time of tissue is in the adventitia of the digestive tube

dense irregular CT with adipose tissue

40

what is the sympathetic innervation of the gut wall

sympathetic postganglionic fibers pass through gut wall to glands and smooth muscle

41

what is the parasympathetic innervation of the gut wall

preganglionic fibers synapse with postganglionic fibers in ganglia within the gut wall itself

42

what does the meissner's plexus regulate

local secretion, blood flow and absorption

43

what does the auerbach's plexus do

coordinates muscular activity of gut wall

44

what is the first line of defense in the gut-associated lymphoid tissue

IgA

45

what secretes IgA

antigen-stimulated B cells in the follicle of the lamina propria

46

what are the functions of the esophagus

digestion (initiated in the mouth)
addition of mucous to food bolus

47

what type of epithelium is in the mucosa of the esophagus

stratified squamous nonkeratinized epithelium

48

what are rugae

longitudinal mucosal folds that are most prominent in an empty stomach

49

where do gastric glands open into

gastric pits

50

what type of glands does the cardia of the stomach contain

mostly mucous glands

51

what type of glands are in the funds of the stomach

gastric glands

52

what type of glands are contained in the body of the stomach

gastric glands

53

what type of glands are contained in the pylorus of the stomach

mucous glands and hormone-secreting enteroendocrine cells

54

what do chief cells secrete

pepsinogen

55

what do parietal cells manufacture

HCL

56

what secretes intrinsic factor

parietal cells

57

what do enteroendocrine cells do

diffuse neuroendocrine cells that secrete hormones and secrete serotonin

58

where are mucous neck cells located

in the narrow portion of the gland near the gastric pit

59

what type of epithelium lines the surface of the stomach and the pit

simple columnar consisting of surface mucous cells

60

where do chief cells predominate

end portion of gastric gland

61

how are parietal cells shaped

large pyramidal shaped, eosinophilic cells

62

what are common ways to increase surface area for absorption in GI tract

increase length of small and large intestines
plicae circulares (valves of kerckring)
villi and microvilli

63

define plicae

folds of the mucosa, each with a submucosal core

64

where do the crypts extend

down between the villi below the bases of the villi

65

what is the epithelium of the wall of villus in the crypt-villus system

simple columnar epithelium

66

what type of plexus does each villus have of the crypt-villus system

capillary plexus

67

what is the blind-ending lympathic in each villus called

lacteal

68

define glycocalyx

glycolipid coat that contains an array of brush border enzymes: maltose, sucrase, isomaltase, lactase, lipase, peptidases

69

what is glycocalyx produced by

small intestine epithelial cells (enderocytes)

70

what are the microvilli in the small intestine supported by

actin filaments

71

how are actin filaments tied to terminal web intermediate filaments

via spectrin fibrils

72

what membrane-linking proteins bind actin filaments to plasma membrane covering the villus

myosin I and calmodulin

73

what actin cross-linking proteins are used to bind actin filaments to each other

villain and fimbrin