Control of Blood Glucose Flashcards
Glucose is the primary fuel used by a few specialized cells, such as?
- Central Nervous System
- Brain
Explain carbohydrate intake and digestion.
MOUTH: Salivary amylase will breakdown our starch dextrins to isomaltose, maltose, maltotriose, lactose, sucrose. (Cellulose will not be effected here).
STOMACH: The low pH will inactivate the salivary amylases.
SI: Pancreatic alpha-amylase will continue the process of breaking down some of these carbs. The ISOMALTOSE, MALTOSE, MALTOTRIOSE, LACTOSE, AND SUCROSE are primarily going to be handled at the mucosal lining.
MUCOSAL LINING: Membrane-bound enzymes (ISOMALTASE, MALTASE, LACTASE, SUCRASE, AND TREHALASE) will breakdown these carbs further and allow for the uptake of GLUCOSE, FRUCTOSE, AND GALACTOSE. CELLULOSE will remain intact and move to the large intestine.
ENTEROCYTE: GLUCOSE, FRUCTOSE, GALACTOSE are brought in and will leave via the BASAL LAMINA and will enter PORTAL CIRCULATION.
Through what transporter does FRUCTOSE use to enter the enterocyte?
GLUT-5 transporter via simple passive diffusion (no ATP needed)
Through what transporter does GLUCOSE use to enter the enterocyte?
SODIUM will enter with GLUCOSE and Na2+ will be pumped out while K+ is pumped in.
ATP is required via Na+/K+ ATPase enzyme
Through what transporter does GALACTOSE use to enter the enterocyte?
SODIUM will enter with GALACTOSE and potassium will be pumped out of the cell.
ATP is required via Na+/K+ ATPase enzyme
(TRUE/FALSE)
Enterocytes are highly efficient at bringing in these carbs to the intestine cell and it is VERY RARE that these carbs will slip past the SI and make it into the large intestine.
TRUE
If that were to happen, diarrhea would result
How does GLUCOSE, FRUCTOSE, GALACTOSE leave the enterocyte?
Exit through the basal lamina via GLUT-2 transporter, entering into circulation, moving towards the liver
Define glycolysis
Utilization of glucose as a source of energy
Glucose will enter into the cell and immediately be phosphorylated using ATP, ultimately being converted into 2 pyruvate molecules.
Define glycogenesis
Storage of glucose as glycogen.
Glucose can be stored as glycogen occurring primarily in hepatocytes and muscle tissues.
Define Glycogenolysis
Release of glucose from storage.
Glycogen can be broken down when needed between meals or times of fasting; Glucose broken off the glycogen chain can be released into the blood from the liver. The glycogen stored in muscle cannot be release, the glucose can be broken down but it will remain in the muscle tissue.
Define gluconeogenesis
Formation of glucose from non-carbohydrate precursors.
Similar process to reverse glycolysis, where we can create glucose in the liver, which can be released into the bloodstream.
Alpha cells of the pancreas
Secrete glucagon.
When BG levels start to decrease, it will act on the hepatocytes to release or to start to break down glycogen stores, resulting in glucose being released to maintain BG levels.
Beta-cells of the pancreas
Secretes insulin.
When BG level rise, insulin is secreted which is required by a number of tissues to activate the glucose transporters to bring glucose into the cells.
What are the EXOCRINE functions of the pancreas?
It synthesizes a number of enzymes that are needed for digestion, such as pancreatic amylase, pancreatic lipase, and bicarbonate
The family of protein carriers involved in glucose being utilized by cells is called?
Glucose transporters (GLUTs)
12 have been identified
