Histology Of Liver, Gallbladder, And Pancreas

Question 1

Main digestive function of liver?

Answer 1

Production of bile (required for emulsifying fats)

Question 2

How is the liver the main interface between digestive system and the blood

Answer 2

Nutrients absorbed in the small intestine are processed in the liver before distribution throughout body

Question 3

Explain the function of hepatocytes with the following

1. Bile
2. Plasma proteins
3. Gluconeogenesis
4. Drugs
5. Urea
6. Storage
7. Iron

Answer 3

1. Produces bile
2. Synthesis and secrete albumin, fibrinogen, apolipoproteins, etc.
3. Converts amino acids into glucose
4. Breaksdown toxins
5. Involved in deamination of amino acids which produces urea
6. Stores glycogen and triglycerides
7. Stores iron in complexes with ferritin

Question 4

Besides hepatocytes, name 2 other types of liver cells and their function

Answer 4

1. Hepatic stellate cells or ito cells- store fat soluble vitamins
2. Kupffer cells- specialized macrophages that aid in removal of old/damaged RBCs and bacteria/debris from blood

Question 5

Most of the outer surface of the liver is covered by?

Outer surface is covered by

Answer 5

Mesothelial cells from peritoneum

Glisons capsule

Question 6

Structure of hepatocytes

Answer 6

Large central nuclei and eosinophilic cytoplasm rich in mitochondria (can also be binucleated)

Question 7

How is the liver parenchyma organized?

Answer 7

As thousands of small hepatic lobules around a central vein

Question 8

2 sources in which the liver receives blood

Answer 8

Portal vein (mostly) and proper hepatic artery

Question 9

Function of sinusoids

Where are they located

Answer 9

Receive blood from portal vein/proper hepatic artery

Between plates of hepatocytes

Question 10

How does blood flow in the liver

How does bile flow?

Answer 10

From periphery to center

Opposite

Question 11

What about the sinusoid structure makes it easier for blood and sinusoid exchange

What else makes this exchange easier

Answer 11

Sinusoids are lined by discontinuous (basal lamina not touching), fenestrated endothelial cells

Space of Disse- space between hepatocytes and endothelial cells that allows direct contact between microvilli of hepatocytes and plasma

Question 12

Liver sinusoids are lined by endothelial cells and what other cells?

Answer 12

Stellate macrophages (Kupffer cells)

Question 13

What cells are located in space of
Disse

Other function of these cells not previously mentioned

Answer 13

Hepatic stellate (Ito) cells; other function is to produce ECM and cytokines to help regulate kupffer cell activity

Question 14

When there is liver disease, what cells can disrupt normal liver function and how?

Answer 14

Liver disease will lead hepatic stellate cells to overproduce collagen. Overproduction of collagen can prevent important communications and impact liver function (leads to fibrosis seen in cirrhosis of liver)

Question 15

Where does bile canaliculi run

What are they sealed by

Answer 15

In between 2 hepatocytes

Sealed by tight junctions

Question 16

Bile canaliculi empty into?

What is unique about answer to first part

Answer 16

Canals of Hering

They are one of the only parts of the biliary tree that have a lining on their own (lined by simple cubodial epithelium - cholangiocytes)

Question 17

Canals of Hering merge in portal areas with

Answer 17

Bile ductules (cubodial or columnar cholangiocytes)

Question 18

What are cholangiocytes

Answer 18

This is what simple columnar epithelium that lines biliary tree is called

Question 19

Layers of the gallbladder

Answer 19

Mucosa, muscularis externa, adventitia/serosa

No submucosa

Question 20

What is unique about the mucosa of gallbladder compared to other parts of GI tract

Answer 20

No muscularis mucosae (just epithelium and lamina propria)

Question 21

Which parts of gallbladder are covered with adventitia?

Serosa?

Answer 21

Adventitia is the surfaces attached to the liver

Serosa is the surfaces unattached to liver that are covered by peritoneum

Question 22

Which cells of the gallbladder function to concentrate bile

How do they do this?

Answer 22

Lining epithelial cells (cholangiocytes)

Actively transport ions (so water will follow passively)

Question 23

What is the main stimulus for contraction of the gallbladder/release of bile

Answer 23

CCK from enteroendocrine cells (mostly in duodenum)

Question 24

Exocrine part of the pancreas consists of?

Endocrine part of the pancreas consists of?

Answer 24

Serous acini

Pancreatic islets/islets of langerhans

Question 25

Structure of acinar cells

Answer 25

Basal nuclei, basal basophilic cytoplasm (b/c lots of rER), and numerous zymogen granules towards apex of cell

Question 26

Name a type of cell that is unique to the pancreas

What are they

Answer 26

Centroacinar cells

Initial cells of intercalated ducts that extend into lumen of acinus

Question 27

How do the intercalated ducts drain

Answer 27

Drain into intralobular ducts-> interlobular ducts -> main and accessory pancreatic ducts

Question 28

How do islets of Langerhans appear in H&E stained sections?

Answer 28

Clusters of pale staining cells surrounded by more intensely staining pancreatic acini

Question 29

Are alpha or beta cells more numerous in islets of langerhans?

Another type of cell here?

Answer 29

Beta

Delta cells- secrete somatostatin

Question 30

Normal level of glucose in the blood

Answer 30

70 mg/dL

Question 31

Function of somatostatin

Answer 31

Inhibits release of other islet cell hormones (thru paracrine action) and suppresses exocrine secretion of pancreas