Accessory Organs of the Digestive Tract

Question 1

Pancreas is what type of gland

Answer 1

Exocrine

Question 2

Liver is what type of gland

Answer 2

Endocrine and exocrine gland

Question 3

Myoepithelial cells

Answer 3

Located b/w epithelial cells and basal lamina

Assist in moving secretory products towards the excretory duct

Question 4

Pathway of saliva flow

Answer 4

Acinus
Intercalated duct (low cuboidal)
Striated duct (simple cuboidal to columnar)
Excretory duct (simple cuboidal to pseudostratified columnar or stratified cuboidal)

Question 5

Parotid glands

Answer 5

Largest salivary gland, may have adipocytes near
Acini consist of only serous secretory cells
Pyramidal cells with basal nucleus and prominent RER
Secretory granules visible in apical region

Question 6

Sublingual glands

Answer 6

Branched tubule-alveolar gland with both serous and mucous cells
Predominantly mucous cells
Intercalated and striated ducts are poorly developed

Question 7

Submandibular gland

Answer 7

Serous cells are predominant, but also has mucous cells
Mucous cell containing acini are capped by serous demilunes
Myoepithelial cells control serous secretions
Intercalated ducts are shorter and striated ducts are longer than those in parotid gland

Question 8

Exocrine vs endocrine pancreas function

Answer 8

Exocrine- synthesizes/secretes enzymes that are essential for digestion in intestine
Endocrine component- synthesizes/secretes hormones (insulin and glucagon) into the blood

Question 9

Exocrine pancreas

Answer 9

Serous acini
Contains pancreatic acinar cells
Intercalated duct begins w/in the acinus
Centroacinar cells, duct cells inside the acinus
^^ they are continuous with low cuboidal epithelium of intercalated duct
Pancreas often confused with parotid glands

Question 10

Acinar vs centroacinar cell staining

Answer 10

Acinar cells stain intensely, centroacinar cells stain lightly

Question 11

Pancreated acinar cell

Answer 11

Well developed ER
Prominent Golgi
Apical domain of zymogen granules that contain tons of proenzymes such as trypsinogen, a-amylase, lipases, ribonuclease

Question 12

Endocrine pancreas

Answer 12

Spherical masses of endocrine cells, surrounded by thin reticular capsule
Islets arise from endodermal epithelial outgrowths

Question 13

a-cells vs b-cells vs d-cells vs PP cells

Answer 13

a - secrete glucagon
b- secret insulin
d- secrete somatostatin (least abundant)
PP- secrete pancreatic polypeptide

Question 14

Liver

Answer 14

Enclosed in thin CT capsule lined with mesothelium of visceral peritoneum
Hepatocytes function in metabolism, storage, and bile production

Question 15

Hepatocytes (histo description) and bile

Answer 15

Large polygonal cells with eosinophilic cytoplasm and microvilli
Large spherical nuclei, man are binucleate, most are tetraploid
Hepatocytes secrete bile that drains into bile canaliculus, which is lined with cholangiocytes b/w hepatocytes
Canaliculi join to eventually contribute to biliary tree

Question 16

Bile function

Answer 16

Fat absorption, excretion of cholesterol, bilirubin, iron and copper

Question 17

Hepatic lobules

Answer 17

Liver parenchyma is organized as hepatic lobules
Hepatocytes form irregular plates radiating from a central vein
Plates are supported by a stroma of reticular fibers, and separated by sinusoids

Question 18

Portal triad

Answer 18

Venule branch of the portal vein
Arteriole branch of the hepatic artery
Bile ductules (1-2), branches of the bile conducting system

Question 19

Hepatic sinusoids

Answer 19

Anastomosing capillaries that perfuse hepatocytes w/portal and arterial blood
Contain Kupffer cells and hepatic stellate cells

Question 20

Kupffer cells

Answer 20

Stellate macrophages within endothelium of sinusoids
Larger than endothelial cells
Detect and phagocytose defective erythrocytes
Distinguishes hepatic sinusoids

Question 21

Hepatic stellate cells

Answer 21

Cells with small lipid droplets that store vitamin A and other fat soluble vitamins

Question 22

Perisinusoidal space (of Disse)

Answer 22

Located b/w hepatocytes and sinusoidal endothelium (discontinuous capillaries)
Creates a potential space for exchange of materials b/w blood and hepatocytes
-microvilli project into this space, which is filled w/plasma
-Increases surface area for exchange of material

Question 23

Bile canaliculi

Answer 23

Anastomosing network of channels formed by hepatocyte plates
End near portal triads
Bile canaliculi drain into canals of Hering, composed of cuboidal epithelial cells called cholangiocytes

Question 24

Bile pathway

Answer 24

Bile canaliculi
Canals of Hering
Bile ductules
Merge and enlarge
Right/left hepatic ducts

Question 25

Portal lobule

Answer 25

Central axis is the bile duct

Identify portal triad–>draw imaginary lines b/w 3 central veins–>this is a portal lobule

Question 26

Liver acinus

Answer 26

Diamond shaped and occupies parts of adjacent classic lobules
Hepatocytes are arranged in concentric zones around short axis
Based on O2 gradient along sinusoids of adjacent lobules

Question 27

Explain how liver damage can be distributed to certain areas based on exposure to toxin etc..

Answer 27

Liver acini have zones that each have different metabolic functions and distribution of hepatic enzymes

Question 28

Classic lobule

Answer 28

Emphasizes endocrine function of hepatocytes as blood flows toward the central vein
-drains blood from portal vein and hepatic artery to the hepatic or central vein

Question 29

Portal lobule

Answer 29

Emphasizes hepatocytes exocrine function and flow of bile from classic lobules toward bile duct in portal triad
Area drained by each bile duct is roughly traingular

Question 30

Hepatic acinus

Answer 30

Emphasizes different oxygen and nutrient contents of blood at different distances along the sinusoids
-major activity of each hepatocyte is determined by location along oxygen/nutrient gradient

Question 31

Zone I-III- cells within and oxygen/nutrient level

Answer 31

Zone I- periportal cells, high oxygen/nutrient
Zone II- medium oxygen/nutrients
Zone III- pericentral hepatocytes, least oxygen/nutrients

Question 32

Gallbladder

Answer 32

Stores and concentrates bile to release into duodenum after a meal
Highly folded mucosa w/simple columnar epithelium (w/microvilli) overlying lamina propria
Muscularis layer w/bundles of muscle fibers oriented in all directions
Has external adventitia where it is against the liver, but has serosa where it is exposed to peritoneal cavity

Question 33

Rokitansky-Aschoff sinuses

Answer 33

Deep diverticula of the mucosa that may extend through muscularis externa
Develop as result of hyperplasia and herniation of epithelial cells through the muscularis externa
Bacteria may accumulate causing chronic inflammation, increased risk of gallstones