Lecture 11 - Digestive Tract

Question 1

how are accessory organs and gland connected to the muscular tube?

Answer 1

via duct

Question 2

def: prominent aggregations of lymphoid tissue within the digestive system

Answer 2

gut-associated lymphoid system (GALT)

Question 3

def: includes the epithelium, supporting lamina propria and thin smooth muscle layer: muscularis mucosae which produce local movement and folding

Answer 3

mucosa

Question 4

def: thick connective tissue layer that contains glands, arteries, veins, lymphatics, and nerves

Answer 4

submucosa

Question 5

def: surrounds the submucosa and is composed of two muscle layers: inner circular and outer longitudinal, they move perpendicularly to one another in peristalsis

Answer 5

muscularis externus

Question 6

def: consists of connective tissue contains blood vessels, nerves, fat, lined by mesothelium in portions of the tract within the peritoneal cavity

Answer 6

serosa/adventitia

Question 7

what are the 4 types of papillae on the dorsal surface of the tongue?

Answer 7

1. filiform
2. fungiform
3. circumvallate
4. foliate

Question 8

def: elongated, conical shape, heavily keratinized, lack taste buds, provide rough surface or movement of food in chewing

Answer 8

filiform papillae

Question 9

def: mushroom shaped, lightly keratinized, contain a few taste buds

Answer 9

fungiform papillae

Question 10

def: large and dome shaped, contain most of the taste buds on the tongue

Answer 10

circumvallate papillae

Question 11

def: continuously flushing taste buds to remove food particles and allow taste buds to process new stimuli

Answer 11

serous glands

Question 12

def: ovoid structures, each containing 50-75 cells, within the stratified epithelium of the tongue and the oral mucosa

Answer 12

taste buds

Question 13

how often do gustatory cells turn over

Answer 13

7-10 days

Question 14

what are the five categories of tastants?

Answer 14

1. metal ions = salty
2. hydrogen ions = sour
3. sugars = sweet
4. alkaloids = bitter
5. amino acids such as glutamate = umami

Question 15

salty and sour tastes produced by what kind of channels and other taste categories are mediated by what kind of receptors?

Answer 15

salty and sour = ion channels
other tastes = G-protein-coupled receptors

Question 16

what kind of protective epithelium is in the mucosa of the oral cavity, pharynx, esophagus, and anal canal

Answer 16

stratified squamous epithelium

Question 17

what are the 3 divisions of muscle in the esophagus?

Answer 17

1. skeletal muscle in the proximal esophagus
2. mixed skeletal muscle in the middle
3. smooth muscle in the distal esophagus

Question 18

def: where the esophagus ends, an abrupt transition from stratified squamous epithelium in the esophagus to simple columnar epithelium in the stomach

Answer 18

gastro-esophageal junction

Question 19

def: columnar epithelium of the stomach replaces the usual stratified squamous epithelium of the esophagus

Answer 19

Barrett’s esophagus

Question 20

def: basic secretory unit of the stomach

Answer 20

gastric gland

Question 21

def: cells that secrete intrinsic factor

Answer 21

parietal cells

Question 22

def: cells that secrete pepsinogen

Answer 22

chief cells

Question 23

what lines gastric pits?

Answer 23

simple columnar epithelium

Question 24

where does the stomach become the duodenum?

Answer 24

the gastroduodenal junction

Question 25

def: identifiable by long gastric pits and glands, containing mucous secreting cells

Answer 25

pyloric stomach

Question 26

def: broad intestinal villi, separated by crypts and containing goblet cells

Answer 26

duodenum

Question 27

def: make up a brush border on the surface of columnar cells of the mucosal epithelium

Answer 27

microvilli

Question 28

def: finger-like projections of the epithelium and lamina propria that project into the lumen

Answer 28

villi

Question 29

def: folds of the mucosal epithelium, lamina propria, muscularis mucosa and submucosa that projects into the lumen, are the most prominent in the jejunum

Answer 29

plicae circulares

Question 30

Brunner's glands are only found in the _______________-

Answer 30

duodenum

Question 31

the villi tend to be longest in the __________ and become shorter towards the _____________

Answer 31

duodenum, ileum

Question 32

lymphoid tissue becomes more prominent in the _________ and is limited in the _______________

Answer 32

ileum, duodenum

Question 33

the proportion of goblet cells in the epithelium increases ___________

Answer 33

distally

Question 34

Plicae circulares are most prominent and numerous in the ______________ and proximal __________ and are generally absent in the proximal ________________ and distal ____________

Answer 34

jejunum, proximal ileum, proximal duodenum, distal ileum

Question 35

def: glands that produce alkaline mucous, they fill the submucosa and open into the mucosa to drain into the lumen

Answer 35

Brunner's glands

Question 36

def: aggregates of lymphoid cells that provide immuno-surveillance and limit growth of pathogenic bacteria

Answer 36

Peyer's Patch

Question 37

def: absorptive cells, tall columnar cells, each with an oval nucleus in the basal half of the cell

Answer 37

enterocytes

Question 38

goblet cell frequency increases from ________ to __________

Answer 38

proximal (duodenum) to distal (ileum)

Question 39

def: located in the basal portion of the intestinal crypts below the stem cells, are exocrine cells with large, eosinophilic secretory granules in their apical cytoplasm, contain enzymes and other proteins that act on bacteria contributing to innate immunity

Answer 39

Paneth cells

Question 40

what lines the large intestine?

Answer 40

mucosa is lined by columnar epithelium with small brush border and many goblet cells

Question 41

are there villi and plicae circularis in the large intestine?

Answer 41

no

Question 42

def: plexus between inner and outer layers of smooth muscle in the muscularis externa, mainly regulates smooth muscle contraction, peristalsis, and gastrointestinal motility

Answer 42

myenteric (Auerbach) plexus

Question 43

def: smaller plexus mostly regulates glandular secretion and membrane transport

Answer 43

submucosal (Meissner) plexus

Question 44

parasympathetic nerve fibers usually _________ digestion

Answer 44

activate

Question 45

sympathetic nerve fibers usually _________ digestion

Answer 45

inhibit

Question 46

what are the 3 main functions of the liver?

Answer 46

1. metabolism of carbs, proteins and fats 2. modification of exogenous substances such as drugs and alcohol 3. formation and exocrine secretion of bile

Question 47

what is the functional unit of the liver?

Answer 47

hexagonal lobules that hepatocytes are arranged in

Question 48

each lobule surrounds a central vein and is bound by __ _________ _______

Answer 48

6 portal triads

Question 49

how does blood flow through each lobule?

Answer 49

centrally toward the central vein and eventually drains into the IVC

Question 50

how does bile flow through each lobule?

Answer 50

peripherally, produced by hepatocytes and collected in the duct

Question 51

both the portal vein and the hepatic arteries drain into _________ ___________ such that blood in the liver makes intimate contact with hepatocytes

Answer 51

fenestrated sinusoids

Question 52

which zone of the hepatic acinus is this: farthest away and is the site of most alcohol and drug detoxification

Answer 52

zone 3

Question 53

which zone of the hepatic acinus receives oxygen first?

Answer 53

zone 1