Digestive Glands

Question 1

Derivation of digestive glands

Answer 1

come from epithelium of the gut tube (endodermal origin)

Question 2

glands assoc. w/ digestive tract

Answer 2

salivary glands, exocrine pancreas, liver

Question 3

Functions of all glands assoc. w/ digestive tract

Answer 3

produce enzymes, bacteriocidal agents and IgA antibodies

Question 4

Liver: main function

Answer 4

produces bile

Question 5

Gallbladder: main function

Answer 5

stores and concentrates bile from the liver

Question 6

Pancreas: main function

Answer 6

produces hormones

Question 7

Glandular structure of salivary glands

Answer 7

acinus (bunch of grapes) + duct system

Question 8

Progression of structures and epithelium in a branched tubulo-alveolar gland

Answer 8

main duct –> lobar duct (columnar stratified) –> interlobular duct (pseudostratified columnar epithelium) –> intralobular duct (cuboidal-to-columnar epithelium) –> striated duct (cuboidal-to-columnar epithelium) –> intercalated duct (squamous epithelium w/ myoepithelial cells) –> acinus (basement membrane, myoepithelial cells, columnar epithelium) SEE PIC

Question 9

functions of salivary glands

Answer 9

lubricating (water and glycoproteins), digestive (salivary a-amylase for carb digestion), immunologic (IgA, lysozymes), protective (ex. pellicles = protective film on teeth)

Question 10

major salivary glands (3)

Answer 10

parotid, submandibular, sublingual

Question 11

parotid gland type and location

Answer 11

purely serous, located anteroinferior to ears

Question 12

submandibular gland type and location

Answer 12

mostly serous w/ some mucous, located beneath mouth

Question 13

sublingual gland type and location

Answer 13

mostly mucous w/ some serous, located beneath tongue

Question 14

characteristic types of salivary glands (1)

Answer 14

1. serous acinus 2. mixed acinus and serous

Question 15

intercalated ducts (intralobular)

Answer 15

found in mixed glands; simple squamous or simple cuboidal

Question 16

appearance of mixed acinar/serous glands on slides

Answer 16

mucous unit has overlying serous demilune (artifact of preparation)

Question 17

striated ducts (intralobular)

Answer 17

secretions drain from intercalated ducts –> striated ducts; basal cell membranes extensively infolded; collections of mitochondria create striations

Question 18

cell functions in striated ducts

Answer 18

simple columnar cells: (1) do ion transport –> modify composition of salivary secretion (2) secrete lysozye and other factors, transport IgA from plasma cells –> saliva

Question 19

interlobular ducts pathway and epithelium

Answer 19

b/t lobules, receive secretions from intralobular ducts and drain into interlobar ducts; mostly pseudostratified columnar, largest ones may have stratified columnar

Question 20

draw table of glands vs. characteristics

Answer 20

see notes/ibook

Question 21

pancreatic secretions into duodenum (2)

Answer 21

(1) proenzymes, activated in gut lumen: amylase, lipase, trypsinogen, ribonuclease (2) water and ions- bicarbonate

Question 22

cholecystokynin

Answer 22

controls activation of proenzymes from pancreas in gut lumen

Question 23

secretin

Answer 23

controls secretion of pancreatic water and ions

Question 24

negative marker for ID of pancreatic tissue on slides

Answer 24

no striated ducts, no myoepithelial cells

Question 25

characteristics of pancreatic ducts and tissue

Answer 25

intercalated ducts w/ retrograde extension into lumen of serous acinus --> forms a population of centroacinar cells; intralobular ducts flow into interlobar ducts --> main pancreatic ducts --> duodenum; islets/islets of langerhans

Question 26

centroacinar cells

Answer 26

found in pancreas; epithelial cells lining intercalated ducts migrate into center of acinus

Question 27

Functions of the liver (5)

Answer 27

(1) protein synth (2) bile secretion (3) detox and inactivation (4) storage (5) gluconeogenesis

Question 28

characteristics of classic liver lobule

Answer 28

portal triads, liver sinusoids, central vein

Question 29

portal triads

Answer 29

triad of hepatic artery branch, portal vein branch, and branch of bile duct around periphery of hepatocyte; bile exocytosed by hepatocytes --> portal triads --> bile ducts

Question 30

liver sinusoids

Answer 30

large diameter, discontinous capillaries w/ large fenestrae, incomplete basement membrane; facilitate exchange b/t blood and basal domain of hepatocytes

Question 31

central vein

Answer 31

liver is centered around central vein; blood flows hepatic artery + portal vein (both in portal triad) --> sinusoids --> central vein; central veins converge to hepatic vein --> IVC inferior to diaphragm --> R atrium

Question 32

kuppfer cells

Answer 32

resident macrophages of the liver, located in endothelium of sinusoids

Question 33

ito cells

Answer 33

involved in vitamin A storage and local immunity; located in perisinusoidal space

Question 34

space of Disse

Answer 34

perisinusoidal space, b/t endothelium of sinusoids and basal domain of hepatocytes (reticular fibers)

Question 35

flow of blood

Answer 35

from hepatic artery and portal vein --> sinusoids --> central vein in center of hepatocyte

Question 36

flow of bile

Answer 36

opposite to blood; exocytosed by hepatocytes --> travels peripherally to portal triads --> bile ducts --> liver

Question 37

epithelium of central vein

Answer 37

simple squamous

Question 38

sinusoid characteristics

Answer 38

discontinuous capillaries to allow larger molecules to pass through wall; space of Disse b/t reticular fibers and endothelium

Question 39

hepatocyte domains

Answer 39

(1) basal (2) lateral (3) apical

Question 40

basal domain of hepatocyte

Answer 40

where hepatocytes interface w/ blood from sinusoids

Question 41

lateral domain of hepatocyte

Answer 41

where hepatocytes interface w/ other hepatocytes; lots of gap junctions for passing materials

Question 42

apical domain of hepatocytes

Answer 42

where two hepatocytes membranes come together to form a canaliculus that bile is secreted into; two tight junctions on either side of canaliculus

Question 43

bile flow from hepatocytes

Answer 43

exocytosed at apical domains -> through canaliculi -> terminal ductules/cholangiols/canals of Herring -> bile duct branches in portal triad

Question 44

what happens if tight junctions of apical domains are blown?

Answer 44

jaundice

Question 45

wall mucosa composition of gallbladder

Answer 45

simple columnar epithelium, lamina propria, NO muscularis mucosa

Question 46

what increases the surface area of mucosa in gallbladder? - outer wall

Answer 46

plicae on lateral cell membranes (mountain range folds), microvilli on apical surfaces

Question 47

endothelium facing lumen of gallbladder

Answer 47

simple columnar epithelium w/ no cilia or microvilli

Question 48

characteristics of outer wall of gallbladder facing peritoneal cavity vs. liver

Answer 48

facing peritoneum = covered by visceral peritoneum; facing liver = covered by adventitia

Question 49

What is the purpose and mechanism of increased surface area of the gallbladder?

Answer 49

necessary for concentration of bile; pumping Na+ and Cl- through lateral walls to intracelluluar space to create osmotic gradient, water leaves the lumen of gallbladder --> more concentrated bile

Question 50

What does the gallbladder do after a fatty meal?

Answer 50

squirts bile into gut to help digest fat