Lecture 11: Histology of the Accessory Organs of the GI tract

Question 1

What are the 3 main digestive glands?

Answer 1

The major salivary glands.

The exocrine pancreas.

The liver (and gallbladder).

Question 2

What are the 5 steps of the pathway of saliva flow from acinus to lumen?

(Name the ducts in order.)

Answer 2

Acinus (sacs)

Intercalated duct.

Striated duct.

Excretory duct.

Lumen.

Question 3

Hallmarks of:

mucous acini

serous acini

mucoserous acini

Answer 3

1. ) cloudier cytoplasm secrete thick glycoprotein product
2. ) clear cytoplasm, secrete water based product
3. ) core of mucous cells surrounded serous demilune

Question 4

Hallmarks of the…

Parotid gland:

Sublingual gland:

Submandibular gland:

Answer 4

serous, has adipose cells, CN VII passes through

has no capsule, CT divides it into lobes

capped by serous demilunes, shorter intercalated and longer striated ducts compared to parotid

Question 5

What sort of secretions come from the parotid gland?

Sublingual gland?

Submandibular gland?

Answer 5

Serous

Mixed, mostly mucous

mixed, mostly serous

Question 6

What are the major cells of the exocrine pancreas?

Answer 6

Pancreatic acinar cells make up the acinus

Centroacinar cels transition between acinus and Intercalated duct

duct cells line the ducts, covered in cuboidal epithelium

Question 7

Describe pancreatic acinar cells

Answer 7

well developed RER and golgi, have granules that secrete zymogens (proteases, lipases and amylases)

Question 8

What cells make up the endocrine pancreas?

Answer 8

a cells (glucagon), B cells (insulin), d cells (somatostatin), PP cells (pancreatic polypeptide)

They make up islets of langherhands (spherical masses surrounded with reticular capsule)

Question 9

Describe the structure of the liver

Answer 9

covered in mesothelium capsule, hepatocytes arranged in cellular “cords” radiatng around a central vein

Question 10

describe the structure of hepatocytes

Answer 10

large polygonal, eosinophilic cells, large sER, Golgi and peroxisomes

drain bile into the bile canaliculus which merge to form the biliary tree

Question 11

What is a hepatic lobule?

Answer 11

hepatocyte cords radiating around a central vein forms a lobule (form a hexagon)

each hepatocyte separated from each other by sinusoids

Each end of the hexagon has a protal triad (a, v and bile canaliculus)

Question 12

What are Kupffer cells?

What are stellate cells?

Answer 12

• macrophages that lie between the hepatocytes and sinusoids, phagocytose old erythrocytes
• stores lipids (vitamins)

Question 13

What is the perisinusoidal space (of Disse)?

Answer 13

also lie between sinusoids and hepatocytes

space of exchange between blood in the sinusoids and hepatocytes

Question 14

What is the bile canaliculi and how does bile leave the liver?

Answer 14

collect the bile made by the hepatocytes > drain into the canals of Hering and to the cholangiocytes that line the bile duct

Question 15

What is a portal lobule?

Answer 15

space between 3 portal veins (imaginary lines forrming a triangle)

basically all the bile made within this triangle drain to the same bile duct

Question 16

What is the liver acinus and what is the significance?

Answer 16

a functional unit of the liver, characterized by diamond shaped space between two lobules

shows distribution of blood flow to the hepatocytes (zone 1 gets the most blood, zone 3 gets the least, but if there’s toxic stuff in the blood this means zone 1 will get the most damage)

Question 17

Describe the features of the gallbladder

Answer 17

highly folded mucosa over the lamina propia, muscularis muscle surrounding the organ

Question 18

Which part of the gallbladder is covered with adventitia, and which part is covered with serosa?

Answer 18

The gallbladder is covered with adventitia where it lies against the liver.

The part of the gallbladder that is exposed is covered with serosa.

Question 19

What are Rokitansky-Aschoff sinuses?

Answer 19

deep diverticular of mucosaa that extend through the muscularis externa of the gallbladder

result of hyperplasia or epithelial cell herniation through the muscularis externa, can get inflamed and increase risk for gallstones