Anatomy and Cell Biology 3309 Lecture Notes - Lecture 14: Pineal Gland, Duodenum, Circadian Rhythm
15 May 2018
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Lecture 14 – Endocrine Pancreas & Pineal Gland
Location of endocrine cells
- Pineal gland is important for farm animals (sheeps, cows) – regulates their behavior and
reproductive cycle
Pancreas
- Pancreas is below the stomach
- Stomach is wedged between the pancreas and duodenum which comes off the pancreas and
forms a C shaped structure
- Epithelial lined tube is the small intestine
- Loose staining mass of tissue has white spots areas that don’t stain as dark is the pancreas
- Other dark staining mass (dark staining nuclei bunched together) at the bottom is spleen
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- Exocrine pancreas is made of secretory acini that have nuclei in the center (centroacinar
cells) → eosinophilia are enzymes and proteins that are secreted
- Globular arrangement of cells stain fairly lightly
- There is no particular organization structurally that can be identified
- There are reddish/pink channels (capillaries) going through the islets of Langerhans
- Islets of Langerhans produce:
o 1. Insulin: decrease blood glucose levels
o 2. Glucagon: increases blood glucose levels by measuring glucose content
- Both hormones act on the body in an antagonistic manner
Pancreatic vascular components
- Exocrine pancreas (acini) have a dual blood supply
- Acinar vascular system: each acinus is supplied by a capillary network that arises from
arterioles that come in and carry blood away
- Acini receive blood that first perfuses the islets of Langerhams (insuloacinar portal system)
- Capillaries form veins (portal system) that then provide capillaries surrounding the acini
- Functional significance: secretion of enzymes by acinar cells is under control of hormone
that is produced by the islets of Langerhans
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Major cell types in the Islets of Langerhans
- Large blood vessels (fenestrated capillaries) are designed to receive hormones produced by
the cells in the islets of Langerhans
- There is no particular morphological arrangement
- It is a loose network of cells that sit side by side and have access to the blood stream
- There are 4 groups of cells:
o Alpha
o Beta
o Delta
o F cells
- Majority of cells are beta cells that produce insulin
- Smaller component are the alpha cells and they produce glucagon
- Delta cells make up a small component (up to 10%) and they produce somatostatin
(regulates activity of alpha and beta cells)
o If the cells are too active, somatostatin down regulates their activity
- F cells produce pancreatic polypeptide
o Activity of exocrine pancreas is under control of islets of Langerhans
o This downregulates enzyme secretion in exocrine pancreas
o Insuloacinar portal system: exocrine cells receive hormones from islets of Lang.
- Cannot distinguish cells by looking at H and E stain
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Lecture 14 endocrine pancreas & pineal gland. Pineal gland is important for farm animals (sheeps, cows) regulates their behavior and reproductive cycle. Epithelial lined tube is the small intestine. Stomach is wedged between the pancreas and duodenum which comes off the pancreas and forms a c shaped structure. Loose staining mass of tissue has white spots (cid:523)areas that don"t stain as dark(cid:524) is the pancreas. Other dark staining mass (dark staining nuclei bunched together) at the bottom is spleen. Exocrine pancreas is made of secretory acini that have nuclei in the center (centroacinar cells) eosinophilia are enzymes and proteins that are secreted. Globular arrangement of cells stain fairly lightly. There is no particular organization structurally that can be identified. There are reddish/pink channels (capillaries) going through the islets of langerhans. Glucagon: increases blood glucose levels by measuring glucose content. Both hormones act on the body in an antagonistic manner. Exocrine pancreas (acini) have a dual blood supply.
