Endocrine Pancreas Flashcards
True or False. Endocirne cells of the pancreas in the islets of langerhans are innervated by adrenergic, cholinger, peptidergic and neurons.
True.
Where on the islets of langerhans are the beta cells mainly located?
In the core
What is the predominantly cell type int he islet of hangerhan?
Beta cells. (60-65%)
Where are the alpha cells located in the islet of langerhan?
Tend to be located near the periphery of the islet
Which cell types have a neuronal appearance and send dendrite-like processes to beta cells.
delta cells
How do the cells of the I of L communicate with each other?
gap junctions
Incoming blood to the I of L goes where first?
to the center of the islet, to the beta cells.
True or false, cells of the I of L have both endocrine and paracrine activitty.
True
In the Golgi, insulin is packaged in vesicle with what _
C peptide.
In the secretory vesicle when insulin is packaged, is the C peptide attached to the insulin?
No. C peptide gets cleaved in the Golgi and is packaged with insulin.
In patients receiving insulin injections, what can be measured to test Beta cell function in type I diabetes?
C peptide
In the beta cells, glucose binds to what type of receptor?
GLUT 2
What the steps in releasing insulin?
- Glucose binds to GLUT2 and comes inside the beta cell.
- Glucose undergoes glycolysis
- ATP is produced
- Increased ATP inside the cell closes K+ channels.
- Cells become depolarized
- Depolarization causes Ca channels to open.
- Ca comes into the cell and causes insulin+C peptide vesicles to Fuse.
- Vesicle is exocytosed, and insulin and C peptides are released.
What type of K channels are found on the pancreatic beta cells which closes due to increased intracellular ATP levels.
Inward-rectifier K channels.
Pancreatic beta cells also contain sulfonyurea receptor which is an important receptor clinically because _
Sulfonylurea drugs (e.g. tolbutamide, glycburide) promotes the closing of ATP-dependent K channels which increases insulin secretion. This is used as a tx for type II DM