Week 4: Histology

Question 1

ID the organ

Answer 1

Liver

Question 2

Name an exocrine product of this organ

Answer 2

Bile, bile salts, bilirubin, and cholesterol

Question 3

Name two endocrine products of this organ

Answer 3

Insulin-like growth factor 1 (IGF-1) and thrombopoetin (TPO), albumin, fibrinogen, prothrombin, transferrin, angiotensinogen, LDL, VLDL, and more.

Question 4

Name a target of the endocrine products: Thrombopoetin (TPO) and Insulin-like Growth Factor 1 (IGF-1)

Answer 4

TPO - megakaryocytes, platelets, and hematopoetic stem cells
IGF-1 - muscle, osteoblasts, chondrocytes, and adipocytes to name a few

Question 5

ID this structure. Be specific

Answer 5

Hepatic Lobule - functioning unit of the liver

1 - Hepatic Portal Vein/Venule
2 - Hepatic Portal Artery/Arteriole
3 - Bile Duct
4 - Central Vein or Terminal Hepatic Venule (THV)

Question 6

Name the thin dark lines seen in the cells immediately surrounding marker #3

Answer 6

Terminal Bars

Question 7

Name the structure whose lumen in indicated by marker #4.

Answer 7

Central Vein or Terminal Hepatic Venule (THV)

Question 8

Name the zone of the parenchymal cells surrounding the structure indicated by marker #4

Answer 8

Zone 3 (Pericentral or Perivenous)

Question 9

Name the zone of the parenchymal cells surrounding the structure indicated by markers #1-3

Answer 9

Zone 1 (Periportal or Perihepatic)

Question 10

Name the zone of the parenchymal cells surrounding the structure indicated by marker #5

Answer 10

Zone 2 (Mid-lobular)

Question 11

Name a function of the liver that predominately occurs in the cells of the zone surrounding marker #4

Answer 11

• Glycolysis
• Lipolysis
• B-catenin/Wnt signalling
• Cytochrome P450 detoxification
• Ammonia metabolism (Urea cycle)

Question 12

Name a function of the liver that predominately occurs in the cells of the zone surrounding markers #1-3

Answer 12

• Gluconeogensis
• Beta-oxidation

Question 13

Name the 3 types of the liver injury that predominately occur in the cells of the zone surrounding marker #4

Answer 13

• MAFLD
• Drug/Alcohol Toxicity
• Parasite Infection Fibrosis

Question 14

Name the 3 types of the liver injury that predominately occur in the cells of the zone surrounding markers #1-3

Answer 14

• Autoimmune Hepatitis
• Iron Overload Injury
• Biliary Cirrhosis

Question 15

Name the very small, dark structure indicated by markers #6 and #7

Answer 15

Bile Canaliculi

Question 16

Name the structure whose lumen is indicated by marker #2

Answer 16

Central Vein or Terminal Hepatic Venule (THV)

Question 17

Name the cells most likely indicated by markers #1, #3, and #4

Answer 17

Kupffer cells/Stellate macrophages

Question 18

Name the structures indicated by A, B, and C

Answer 18

Portal Triad (Vein, artery, and bile duct), respectively

Question 19

ID the cells indicated by arrow D with 2 features that allow you to identify it

Answer 19

Hepatocyte

1 - binucleated
2 - you can see the portal triad

Question 20

ID markers i, ii, and iii

Answer 20

i - common bile duct
ii - hepatic portal vein
iii - proper hepatic artery

Question 21

Where would you predict Phase I oxidations would occur? List the marker identifying that region along with the zone name.

Answer 21

Marker #6; Zone 3 (Pericentral or Perivenous)

Bile flows opposite of blood in the liver, so first steps occur near THV and later steps near the triad.

Question 22

Where would you predict Phase II conjugation with glucuronic acid would occur? List the marker identifying that region along with the zone name.

Answer 22

Marker #4; Zone 1 (Periportal or Perihepatic)

Bile flows opposite of blood in the liver, so first steps occur near THV and later steps near the triad.

Question 23

The liver’s modification reactions can sometimes produce toxic molecules that damage the liver. What cells are known to be activated in response to damage?

Answer 23

Stellate cells

Question 24

ID the organ and two features that allow you to identity it

Answer 24

Gall bladder

may also see Hepatocytes if the section is taken on the superior side

1 - capsule
2 - lack of submucosal layer
3 - the squiggly microscopic appearance

Question 25

Drugs and other compounds that are amphipathic and larger than approximately 300 MW are often secreted into the bile by hepatocytes, with or without modification. This is considered a route to eliminate such compounds from the body. What activity involving the liver and bile secretion could reduce the effectiveness of this mode of elimination?

Answer 25

Enterohepatic recirculation ## Footnote This would return the excreted drug back to the liver from the small intestine via the portal vein

Question 26

ID the organ

Answer 26

Liver

Question 27

Are there any abnormalities in this organ?

Answer 27

Yes ## Footnote Many cells are enlarged with pale droplets - lipids/fatty acids in hepatocytes

Question 28

Name the cells most likely indicated by marker #2

Answer 28

Hepatocyte

Question 29

Name the cells most likely indicated by marker #1

Answer 29

Adipocyte

Question 30

What substance does the cell labeled #2 contain that it usually doesn't?

Answer 30

Lipid/Fatty acids

Question 31

Studies have shown that cellular changes can take place even after moderate alcohol consumption, and that these changes are reversible. Propose a simple mechanism for these cellular changes with the diagram below.

Answer 31

Increased/Excess NADH from ethanol going to Acetyl-CoA will alter metabolism by being consumed in the process of going from Acetyl-CoA to Fatty acids

Question 32

**ID the organ**

Answer 32

Gall bladder | may also see Hepatocytes if the section is taken on the superior side

Question 33

Name the tissue indicated by Marker #1

Answer 33

Simple columnar epithelium

Question 34

What layer(s) are absent in this organ?

Answer 34

Submucosa (likely muscularis mucosae as well)

Question 35

Name a hormone that acts upon this organ

Answer 35

Cholecystokinin (CCK) ## Footnote The roots of CCK tell you what it does: chole-: bile/gall cyst/o: bladder -kinin: movement i.e. gall bladder movement

Question 36

ID the organ

Answer 36

Liver

Question 37

Describe some abnormalities seen in this biopsy

Answer 37

This is hemochromatosis; too much iron is absorbed and thus stored in organs such as the liver. Note location is Zone #1 (Periportal) ## Footnote Markers #1 and #2 are pointing to iron deposits

Question 38

Name the parenchymal cells most likely affected by the condition shown

Answer 38

Zone 1 (Periportal or Perihepatic) ## Footnote Hemochromatosis is excess iron deposited in organs like the liver. This results in iron overload injury that affects Zone 1 (Periportal or Perihepatic) cells

Question 39

**ID the structure**

Answer 39

Hepatic Portal Triad ## Footnote A - Bile duct B - Hepatic Portal Vein/venule **C - Proper Hepatic Artery/arteriole**

Question 40

In response to hepatic injury, the stellate cells can transform into what cell types?

Answer 40

Fibrogenic Myofibroblasts