Blood Glucose Regulation ✅ Flashcards
(33 cards)
What organ plays a major role in the regulation of blood glucose concentrations?
The pancreas
What is the embryological origin of the pancreas?
Endodermal, arising from the embryonic foregut
What happens to the pancreatic bud endoderm in embryological development?
Islet cell clusters differentiate from the pancreatic bud endoderm. These cell clusters from acini and ducts. On the edge of these cell clusters, pancreatic islets form
What are Pax genes?
A family of genes coding for tissue specific transcription factors
What Pax genes are involved in pancreatic embryological development?
Pax-6 and Pax-0
What does Pax-6 do?
Facilitates development of pancreatic β and δ cells
What do pancreatic β-cells release?
Insulin
What do pancreatic δ-cells release?
Somatostatin
What does Pax-0 do?
Facilitates development of α and γ cells
What do pancreatic α cells release?
Glucagono
What do pancreatic γ cells release?
Pancreatic polypeptide
When is fetal endocrine function evident?
10-15 weeks
What cells regulate pancreatic endocrine function?
Islets of Langerhans
Describe the structure of the Islets of Langerhans?
Insulin secreting beta cells occupy the central part, and are surrounded by a ring of glucagon secreting alpha, and somatostatin secreting delta cells.
Why are the Islets of Langerhans well vascularised?
To facilitate rapid hormone release
What innervates the Islets of Langerhans?
Sympathetic and parasympathetic neurones
What does the Islets of Langerhans being innervated by sympathetic and parasympathetic nervous system imply?
There is a neurological contribution to pancreatic endocrine function
What happens when blood glucose levels rise after feeding?
Insulin is secreted
What does insulin do?
- Converts glucose to glycogen
- Facilitates cellular uptake of glucose
What happens when glucose is taken up by cells in response to insulin?
It is converted to glucose-6-phosphate
What happens when glucose levels fall during fasting?
Concentrations are maintained through secretion of glucagon
What does glucagon do?
Facilitates glucose production through glycogenolysis
What other hormones contribute to gluconeogenesis?
Other counter-regulatory hormones such as cortisol, growth hormone, and adrenaline.
How do other counter-regulatory hormones contribute to gluconeogenesis?
Through protein degradation and lipolysis
