Diabetes (Welch) Flashcards
Does a diabetic have more or less glucose in saliva than non-diabetic ,and what does this mean for caries risk?
- More glucose
2. Increased caries risk
What is a concern for a diabetic who has a periodontal infection?
Infection can lead to increased blood sugar making diabetes harder to control
Diabetics are susceptible to what oral problems beyond caries and decreased healing?
- Xerostomia
- Candida infections
- Sores/ulcers
Before Insulin was discovered in 1921, what type of disease was Type I diabetes?
Wasting, fatal w/in weeks to years of onset
The majority of diabetes today is which type: Type I or Type II?
90% Type II
10% Type I
What percentage of the pancreas is exocrine?
98%
What percentage of the pancreas is endocrine?
2%
What is the functional unit of the pancreas?
Islet of Langerhans
What are 4 cell types in the Islets of Langerhans in Pancreas?
- Alpha Cells
- Beta Cells
- Delta Cells
- F or PP Cells
Alpha cells in the Islets of Langerhans in the Pancreas secrete what?
Glucagon
Beta cells in the Islets of Langerhans in the Pancreas secrete what?
Insulin
Delta cells in the Islets of Langerhans in the Pancreas secrete what?
Somatostatin
F or PP cells in the Islets of Langerhans in the Pancreas secrete what?
Pancreatic Polypeptide
What links the chains of Insulin as it matures?
Disulfide bonds
How many chains are in mature insulin and by what are they connected?
2 chains, linked by disulfide bonds
What is cleaved off of Proinsulin to make it into Insulin when the body needs it?
C-peptide
Why is C-peptide tested for in diabetics as a sign of insulin amount?
C-peptide is 1:1 for insulin
Because the disulfide bonds are far apart in insulin, it makes them easily cleaved by insulinase, resulting in a long or short half-life?
Short
The first precursor of insulin, Preproinsulin is synthesized where in the Beta Cell?
Rough endoplasmic reticulum
Loss of what converts Preproinsulin to Proinsulin, the direct precursor to Insulin?
Loss of hydrophobic signal sequence
The Proinsulin is transported to where and packaged with what?
Transport to Golgi
Packaged with PC2 and PC3 endopeptidases
What 2 things are created when Proinsulin is cleaved in the Beta cell?
- Insulin
2. C-peptide
Will Insulin be created if the endopeptidases don’t cleave?
No. This is one of the ways you can get Type II diabetes
Majority of the Pacreatic Islets are what cell type?
Beta
Insulin is a hormone used when: times of plenty or fasting?
Times of plenty
What are 3 general things Insulin does after a large meal?
- Increase fats
- Increase proteins
- Increase sugar storage
Glucagon, secreted by the Alpha cells of the Pancreatic Islets, is a hormone for when: times of plenty or fasting?
Fasting
What are 3 things Glucagon increases during fasting?
- Increase glycogenolysis
- Increase gluconeogenesis
- Increase ketogenesis
What is a normal glucose level range?
90-110
What is the general problem in a diabetic with meals?
Glucose increases but never goes back down to a baseline, so blood sugar remains high
How is the liver involved in diabetes?
Due to glucose not being used by cells in a diabetic, the liver goes into constant gluconeogenesis thinking there is a lack of glucose
What is gluconeogenesis?
Production of glucose from proteins in the liver
For Type II diabetes, what is the pancreatic problem?
Decreased insulin secretion
For Type II diabetes, what is the body tissue problem?
Decreased glucose uptake
What is a layman’s way to describe diabetes?
Starving at a banquet
Any glucose not used by a cell for energy is stored as what?
Glycogen
What is a byproduct of gluconeogenesis, the breakdown of proteins to make glucose for energy?
Urea byproduct is created
What is a byproduct of lipid breakdown for energy?
Create free fatty acids and ketone bodies
What is a byproduct of lipid breakdown for energy?
Free fatty acids and ketone bodies
What is the only way for glucose to get into a cell from the blood?
Insulin must bind a receptor on the cell
When insulin binds to a cell and glucose is let in, what is done in the cell?
Gluco-1-phosphatase is used for energy. Glucose not used for energy is stored as Glycogen via glycogen synthetase. Proteins and lipids are stored.
What decreases when Insulin binds its receptor and allow glucose into the cell?
- Gluconeogenesis decreases, decreasing urea excretion
2. Lipase decreases, decreasing FFA and Ketone bodies
What is the problem at the cell level when Insulin is either not present and doesn’t bind the receptor or is not functional to bind the receptor?
Glucose does not enter the cell so blood stays hyperglycemic. Cell breaks down glycogen stores to use for energy
What does the cell move onto when its glycogen stores are depleted in a diabetic with either no insulin, or non-functional insulin?
Gluconeogenesis increases causing increased Urea excretion and decreased amino acid excretion
What will a diabetic have in their urine that indicates they are undergoing gluconeogenesis for energy?
Azoturia = high concentration of nitrogen in urine
After gluconeogenesis has depleted the proteins in the cell, what is used for energy in the diabetic?
Lipids are broken down via lipase increasing free fatty acid excretion causing hyperlipidemia in the blood and increasing ketone bodies in the liver
If a diabetic is acidotic due to high amounts of free fatty acids overwhelming the liver, what physical sign will be seen?
Hyperventilation
What molarity is diabetic blood: hyperosmolar or hypoosmolar?
Hyperosmolar
What will body try to do to hyperosmolar blood?
Dilute it by sucking fluid out of tissues
With inherited insulin resistance common in Type II diabetes, what will occur with Normal Beta Cell function?
Beta cells will hypersecrete causing compensatory hyperinsulinemia making person normoglycemic for a time
With inheritied insulin resistance common in Type II diabetes, what will occur once the Beta cells stop their hyperfunctioning to compensate for the insulin resistance?
Beta cells secrete less insulin leading to an insulin deficiency, hyperglycemia, and Type II diabetes
What stimulates the Beta cell to secrete insulin and via what transporter?
Glucose enters Beta cells via GLUT 2
What phosphorylates glucose to its energy usable glucose-6-phosphate?
Glucokinase
Glycolysis and oxidative metabolism of glucose?
ATP
What causes the secretion of insulin from the Beta cells?
increase of ATP closes ATP sensitive K channels causing cell depolarization which opens Calcium channels leading to an increase of intracellular calcium that causes insulin granules to fuze with Beta cell membrane and secrete insulin via exocytosis
Kinases always do what?
Phosphorylate things
To have the excretion of a transmitter, you have to have an influx of what?
Calcium
What is the most important stimulus for insulin secretion?
Glucose
Is insulin excreted in one or two phases?
Two phases.
First phase: Exocytosis of insulin at the membrane.
Second phase: An hour or so later
An increase in plasma glucose does what to Beta cells of the pancreas?
Stimulates beta cells
Does an increase in plasma glucose stimulate Pancreatic Alpha Cells?
No
What is the negative feedback for Beta cells?
They dump insulin which causes blood glucose to drop. A decrease in blood glucose stops Beta cell stimulation
Does a Type II diabetic have the first phase insulin dump that is found in a normal person?
No
What subunit of the insulin receptor is transmembrane?
Beta subunit
What second messenger is the insulin receptor linked to?
Tyrosine kinase