Endocrine Flashcards
What is a permissive effect in terms of hormones?
When the presence of one hormone is required in order for another hormone to exert its full effects on a target cell. E.g. Thyroid and reproductive hormones.
What is a synergistic effect in terms of hormones?
The effect in which two or more hormones work together to produce a combined effect, that cannot be observed by a single hormone alone. E.g. FSH and oestrogen.
What is an antagonistic effect in terms of hormones?
Opposing effects on one another. E.g. Insulin and glucagon, are antagonistic hormones because insulin works to lower blood glucose levels while glucagon works to raise blood glucose levels.
What area in the pancreas creates and releases hormones?
Islets of langerhans
What are the 3 types of cells that produce hormones? (Also one extra)
Alpha, beta and delta cells in the pancreatic islets. Also pancreatic polypeptide cells.
Do endocrine or exocrine cells produce hormones?
Endocrine produce hormones, exocrine cells secrete panreatic juices.
What do alpha cells produce, at what % and what are they stimulated by?
Alpha cells:
- 20% produce glucagon
- low glood glucose stimulates
What do beta cells produce, at what % and what are they stimulated by?
Beta cells:
- 75% produce insulin
- high blood glucose stimulates
What are the 4 different hormone classes?
Amine, peptide, protein and steroid hormones (in the order of simplest to complex).
In what way do lipid soluble hormones travel?
- Hormone diffuses through plasma membrane.
- Binds with receptor in the cytoplasm (forming receptor hormone complex).
- The complex then enters the nucleus and triggers gene transcription.
- Transcribed mRNA is translated into proteins that alter cell activity.
How do water soluble hormones travel?
MORE COMPLEX
- They are membrane insoluble.
- Bind to membrane receptors
- The binding activates a G protein (transmit signals from out to inside cell).
- The activated G protein activates adendyl cyclase.
- Adendyl cyclase catalyses the conversion of ATP to cAMP.
- Protein kinases phosphorylate proteins in the cytoplasm. This activates these proteins allowing them to alter cell activity.
What are the 2 hormones produced by the pancreas?
Insulin and glucagon
What does insulin do?
Made by beta cells in the pancreas, insulin moves glucose from the bloodstream into bodys cells to make energy. When blood glucose is high insulin is released and lowers this level.
What does glucagon do?
Made by alpha cells in the pancreas, glucagon breaks down glycogen in liver = glucose, this glucose is then secreted into the bloodstream. When blood glucose is low glucagon is released and raises this level.
What is the function of somatostatin?
Inhibits the release of insulin and glucagon.
What is the function of pancreatic polyeptide hormone?
Role in appetite and regulation of pancreas endo and exo secretions. Released after a meal - can decrease food consumption.
