[01] Insulin Secretion Flashcards
(27 cards)
Where are pancreatic beta cells located?
In the islets of Langerhans within the pancreas
What organ is adjacent to the pancreas?
Duodenum
What are islets of Langerhans?
Endocrine part of the pancreas
What other cell type is present in islets besides beta cells?
Alpha cells
What do alpha cells secrete?
Glucagon
What transporter allows glucose into beta cells?
GLUT2
What enzyme phosphorylates glucose in beta cells?
Glucokinase
What is the product of glucose phosphorylation?
Glucose-6-phosphate
What metabolic pathways follow glucose phosphorylation?
- Glycolysis
- TCA Cycle
What ion channel closes due to an increased ATP/ADP ratio?
K-ATP channels
What is the effect of K-ATP channel closure?
Membrane depolarization
Which ion channels open due to membrane depolarization?
Voltage-dependent calcium channels
What ion enters the cell causing insulin granule mobilization?
Ca^2+
How is insulin released from beta cells?
Exocytosis of insulin-containing granules
How do beta cells sense increased blood glucose?
Through glucose transporters and glycolytic enzymes
What metabolic signal leads to insulin release after food ingestion?
Increase in ATP/ADP ratio
What happens to insulin when blood glucose normalizes?
Secretion diminishes, forming a feedback loop
What are the target cells for insulin?
- Liver
- Muscle
- Adipose tissue
What hormone can modulate insulin secretion?
GLP-1
What neurotransmitters can modulate insulin secretion?
Various (not specified)
What pathological condition can result from dysfunction in insulin secretion?
Type 2 diabetes mellitus
GLUT2 - Initials
Glucose Transporter 2
ATP - Initials
Adenosine Triphosphate
ADP - Initials
Adenosine Diphosphate
