lect 32 & 33-Upper GI histology

Question 1

what is the epithelium of the GI tract

Answer 1

stratified squamous at either end

simple columnar most of the length

Question 2

what type of muscle is in the GI tract

Answer 2

skeletal at either end (including upper esophagus)

smooth muscle throughout most of length

Question 3

what is the GI intrinsic rhymicity mostly due to

Answer 3

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

Question 4

what are the peptide neurotransmitters

Answer 4

bombesin
motilin
vasoactive intestinal peptide

Question 5

what do unicellular endocrine cells secrete

Answer 5

secrete neuropeptides

Question 6

what are unicellular endocrine cells derived from

Answer 6

endoderm

Question 7

what are intrinsic nerve fibers derived from

Answer 7

neural crest

Question 8

what does the mucus membrane of the lip consist of

Answer 8

stratified squamous epithelium
basement membrane
lamina propria

Question 9

what 3 embryonic tissues interact in the development of teeth

Answer 9

ectoderm, neural crest and mesoderm

Question 10

what gves rise to dental papilla

Answer 10

neural crest and mesoderm

Question 11

what forms the enamel organ

Answer 11

ectoderm

Question 12

what is the dental primordium formed from

Answer 12

basal cels of the oral ectoderm

Question 13

what is the labiodental lamina

Answer 13

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

Question 14

what is the dental lamina

Answer 14

internal limb (teeth)

Question 15

what is the dental sac

Answer 15

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

Question 16

what forms the dentin matrix through the life of the tooth

Answer 16

odontoblasts

Question 17

define tomes’ dentinal fibers

Answer 17

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

Question 18

what type of collagen in dentin primarily composed of

Answer 18

collagen type 1

Question 19

what forms the enamel which covers only the tooth crown

Answer 19

ameloblasts

Question 20

what is the hardest substance in the body

Answer 20

enamel

Question 21

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

Answer 21

amelogenins and enamelins

Question 22

what does pulp originate from

Answer 22

dental papilla containing condensed mesenchyme

Question 23

what is the periodontal membrane

Answer 23

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

Question 24

what binds the cementum to the bony socket

Answer 24

periodontal membrane

Question 25

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

Answer 25

sulcus terminalis

Question 26

what are lingual papillae formed of

Answer 26

central core of CT lamina propria covered by stratified squamous epithelium

Question 27

what are the 2 types of cells of taste buds

Answer 27

sustantacular cells and taste cells

Question 28

what are sustentacular cells

Answer 28

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

Question 29

what does the basal part of taste cells secrete

Answer 29

neurotransmitters

Question 30

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

Answer 30

ionic transport

Question 31

what does sour taste sensation involve

Answer 31

hydrogen ion blockage of potassium ion channels to cause depolarization

Question 32

what does bitter taste involve

Answer 32

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

Question 33

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

Answer 33

stratified squamous transitioning to simple columnar

Question 34

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

Answer 34

loose areolar CT associated with epithelium

Question 35

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

Answer 35

dense, irregular CT

Question 36

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

Answer 36

meissner's plexus

Question 37

what are the functions of muscular is externa

Answer 37

regulates size of lumen | regulates rhythmic movement of GI tract

Question 38

what is tissue of the serosa of the digest tube

Answer 38

dense irregular CT | layer of submesothelial Ct

Question 39

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

Answer 39

dense irregular CT with adipose tissue

Question 40

what is the sympathetic innervation of the gut wall

Answer 40

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

Question 41

what is the parasympathetic innervation of the gut wall

Answer 41

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

Question 42

what does the meissner's plexus regulate

Answer 42

local secretion, blood flow and absorption

Question 43

what does the auerbach's plexus do

Answer 43

coordinates muscular activity of gut wall

Question 44

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

Answer 44

IgA

Question 45

what secretes IgA

Answer 45

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

Question 46

what are the functions of the esophagus

Answer 46

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

Question 47

what type of epithelium is in the mucosa of the esophagus

Answer 47

stratified squamous nonkeratinized epithelium

Question 48

what are rugae

Answer 48

longitudinal mucosal folds that are most prominent in an empty stomach

Question 49

where do gastric glands open into

Answer 49

gastric pits

Question 50

what type of glands does the cardia of the stomach contain

Answer 50

mostly mucous glands

Question 51

what type of glands are in the funds of the stomach

Answer 51

gastric glands

Question 52

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

Answer 52

gastric glands

Question 53

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

Answer 53

mucous glands and hormone-secreting enteroendocrine cells

Question 54

what do chief cells secrete

Answer 54

pepsinogen

Question 55

what do parietal cells manufacture

Answer 55

HCL

Question 56

what secretes intrinsic factor

Answer 56

parietal cells

Question 57

what do enteroendocrine cells do

Answer 57

diffuse neuroendocrine cells that secrete hormones and secrete serotonin

Question 58

where are mucous neck cells located

Answer 58

in the narrow portion of the gland near the gastric pit

Question 59

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

Answer 59

simple columnar consisting of surface mucous cells

Question 60

where do chief cells predominate

Answer 60

end portion of gastric gland

Question 61

how are parietal cells shaped

Answer 61

large pyramidal shaped, eosinophilic cells

Question 62

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

Answer 62

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

Question 63

define plicae

Answer 63

folds of the mucosa, each with a submucosal core

Question 64

where do the crypts extend

Answer 64

down between the villi below the bases of the villi

Question 65

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

Answer 65

simple columnar epithelium

Question 66

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

Answer 66

capillary plexus

Question 67

what is the blind-ending lympathic in each villus called

Answer 67

lacteal

Question 68

define glycocalyx

Answer 68

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

Question 69

what is glycocalyx produced by

Answer 69

small intestine epithelial cells (enderocytes)

Question 70

what are the microvilli in the small intestine supported by

Answer 70

actin filaments

Question 71

how are actin filaments tied to terminal web intermediate filaments

Answer 71

via spectrin fibrils

Question 72

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

Answer 72

myosin I and calmodulin

Question 73

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

Answer 73

villain and fimbrin