Blood Glucose And Pancreas - Module 5 Flashcards
What are the two functions of the pancreas?
- Exocrine gland
- Endocrine gland
What is the exocrine function of the pancreas?
To produce and release enzymes into the duodenum
What is the duodenum?
Top of the small intestine
What enzymes does the exocrine gland of the pancreas release?
Amylases - carbohydrates to glucose
Proteases - proteins to amino acids
Lipases - lipids to fatty acids/glycerol
What is the endocrine function of the pancreas?
To release insulin and glucagon
What is an islet of langerhans?
Portion of endocrine tissue in the masses of exocrine tissue in the pancreas
Contains beta and alpha cells secreting insulin and glucagon respectively
How are blood glucose levels increased?[3]
- Diet
- Glycogenolysis
- Gluconeogenesis
What is glycogenolysis?
When glycogen is converted to glucose
What is gluconeogenesis?
Conversion of non carbohydrate molecules to glucose
How are blood glucose levels decreased?
- Respiration - glucose is used by cells to release energy
- Glycogenesis
What is glycogenesis?
Production of glycogen
When is insulin secreted?
When beta cells detect a rise in blood glucose levels
When is glucagon secreted?
When alpha cells detect a fall in blood glucose levels
How does insulin cause blood glucose levels to fall?
Binds to cell surface receptors changing tertiary shape causing glucose transport channels to open
Describe the control of insulin secretion in beta cells
At normal levels K+ ion channels are open and actively diffuse out of beta cells
- Glucose levels rise and enter beta cell
- Glucose is metabolised to for ATP
- ATP causes K+ ion gates to close stopping then from leavening the cell
- As k+ ions can no longer leave cell, potential difference reduces cause depolarisation
- Depolarisation causes Ca2+ ion gates to open and diffuse into cell
- Ca2+ ions cause secretory vesicles to fuse to cell membrane and release insulin by exocytosis
