Histology Dissection 7 Lab Objectives

Front 1

ID a classic lobule

Back 1

Lobules vary from 3 to seven or 8 sided, but the rare classical hexagon is rarely seen. The lobule is outlined by connective tissue, but in humans this outline is rarely seen.

Front 2

ID a portal canal

Back 2

Portal canals are located at the vertices of the classic lobule consisting of an artery/vein arteriole/venule, lymphatic duct, bile duct, and autonomic nerves. A continuous layer of hepatocytes surrounds the portal canal as a wall ("mura")

Front 3

ID a portal vein

Back 3

Largest lumen in the portal canal. Contains a thin tunica media and a thick tunica adventitia.

Front 4

ID a hepatic artery

Back 4

Thick tunica media with visible smooth muscle.

Front 5

ID a bile duct

Back 5

Lined with simple cuboidal epithelium.

Front 6

ID a lymphatic duct

Back 6

Consists of a thin endothelial layer

Front 7

ID a central vein

Back 7

At the center of a lobule. In a pig there is a lot more CT surrounding the central vein. Lines of sinusoids are directed towards the central canal like spokes on a bicycle .

Front 8

ID a sinusoid

Back 8

also known as discontinuous capillaries are in between the plates of hepatocytes. They are lined with endothelium.

Front 9

ID a hepatic artery

Back 9

Thick tunica media with visible smooth muscle.

Front 10

ID a bile duct

Back 10

Lined with simple cuboidal epithelium.

Front 11

ID a lymphatic duct

Back 11

Consists of a thin endothelial layer

Front 12

ID a central vein

Back 12

At the center of a lobule. In a pig there is a lot more CT surrounding the central vein.

Front 13

ID a sinusoid

Back 13

also known as discontinuous capillaries are in between the plates of hepatocytes. They are lined with endothelium and drain into the central vein.

Front 14

ID endothelial cells

Back 14

These line the sinusoids and contain reticular fibers that may have a unique stain

Front 15

ID lipocytes

Back 15

Clear cytoplasms that look like minuature unilocular fat cells. These cells store vitamin A.

Front 16

ID sublobular veins

Back 16

Sublobular veins are much larger than central veins and can be found between lobules surrounded by connective tissue. There are no sinusoids draining into these veins that are surrounded by a thin layer of tunica adventitia.

Front 17

ID the space of Disse in the LM

Back 17

The space of disse is located between the hepatocytes and the sinusoids see HA 10.

Front 18

ID the Bile Canaliculi.

Back 18

In longitudinal sections they are seen outlining the borders between hepatocytes. In cross section they appear as circles at the edges of hepatocyte boundaries.

Front 19

ID the Kupffer cells

Back 19

Kupffer cells are macrophages that form part of the lining of the sinusoid and bulge into the sinusoid lumen. They phagocytose trypan blue and so become easily distinguishable with that stain.

Front 20

ID the epithelium of the gall bladder in the light microscope

Back 20

Simple columnar epithelium with microvilli and visible terminal bars (junctional complex). Lateral interdigitations are evident by the dilations of the lateral intercellular spaces.

Front 21

ID the lamina propria

Back 21

loose connective tissue below the epithelium. Contains fenstrated capillaries, small venules, lymphocytes and plasma cells (no lymphatics). Lymphatics are different from lymphocytes.

Front 22

ID the muscularis externa

Back 22

This smooth muscle is randomly arranged unlike that of the gut. Its boundaries with the LP are quite distinct.

Front 23

ID the fibrosa

Back 23

Located in parts of liver that are not covered with visceral peritoneum (the side interfacing with the liver). Below the muscularis externa, it cotins large blood vessels, adipose tissue and sections of dense irregular CT.

Front 24

ID the serosa

Back 24

On the free side of the gall bladder. The layers of Lamina Propria and, muscularis externa and serosa are much thinner than the side with fibrosa. One is able to see the simple squamous epithelium lining the fibrosa.

Front 25

ID the acinar cells

Back 25

Very polarized cells. The apex is filled with acidophilic secretory granules that stain lightly and they have a basophilic base that stains darkly with hematoxylin because of rough ER. Acinar cells are pyramidal and arranged around a small lumen.

Front 26

ID the centroacinar cells

Back 26

Centroacinar cells represent the beginning of a duct within the acini. This arrrangement is unique to the pancreatic exocrine system. In the LM one can visualize the nucleus of the centroacinar cell at the center of the acinus. The arrangement looks like a flower with the acinar cells as the petal and the centroacinar cell nucleus as the stamen/pistil.

Front 27

ID the intercalated ducts (intralobular ducts)

Back 27

Intercalated ducts can be found amongst the acini lined with simple squamous epithelium. They are easily distinguished from the pyramidal acinar cells as shown in slide 27.

Front 28

ID the interlobular ducts

Back 28

Inter lobular ducts are are distinguished from intralobular (intercalated) by the connective tissue sheath that surrounds them. Interlobular ducts are lined with simple columnar/cuboidal epithelium.

Front 29

ID the islets of Langerhans

Back 29

The islets are highly vascularized and can be distinguished from the acini by their nonpolarized swarms of cells.