Flashcards in Diabetes Deck (79):
This is the dominant fuel of cellular energy and requires close regulation.
What is completely dependent on glucose?
What cells are the primary regulators of glucose?
Cells of the Islets of Langerhans
Where are the cells of the islets of Langerhans located?
What 3 cell types do the islets contain?
What do alpha cells secrete?
What is the percentage of cells that are alpha cells
What is the percentage of cells that are beta cells?
What is the percentage of cells that are delta cells?
What hormone do beta cells make?
What hormone do delta cells make?
What is the role of glucagon, insulin, and Somatostatin?
Regulate blood glucose
When is insulin secreted by beta cells?
Increasingly secreted into the blood when glucose is available for cell use
Do beta cells have a direct or indirect relationship with glucose?
Direct- more glucose= more insulin secretion
When is glucagon secreted from alpha cells?
When blood glucose levels are depressed
Do glucagon and insulin have a direct or indirect relationship?
As glucose is _______ in the intestine, insulin is ________.
As glucose is absorbed in the intestine, insulin is secreted
What does the secretion of insulin stimulate?
Cell uptake, utilization, and storage of glucose
What is insulins effect on the liver called?
What happens when ample amounts of glucose are available?
Higher insulin levels promote the formation of glycogen as a means of storing glucose for a later use
What does insulin do to the hepatic synthesis of free fatty acids?
Insulin activates the hepatic synthesis of free fatty acids from glucose which enter the blood and are carried to adipose tissue for storage.
What happens when glucose levels fall?
When glucose levels fall, insulin secretion declines and cell utilization and uptake of glucose is reduced.
What 2 pathways does low levels of glucose activate?
What is glucose produced from?
The breakdown of glycogen in glycogenolysis
What is synthesized in gluconeogenesis?
Describe Diabetes Mellitus
-Major disease involving the islet cell hormones.
-Single most common endocrine disorder.
-Metabolic disorder that has wide-ranging and serious effects.
-Two different forms : Type 1 and Type 2.
What can cause Type 1 DM?
-Viral (environmental factors)
What type of cells are destroyed in Type 1 DM?
What is a direct cause of beta cell destruction?
(not producing insulin, so blood sugar levels rise, and this results in hyperglycemia)
If you have hyperglycemia, what is excreted in urine?
(The glomerulus is unable to filter out the elevated amounts of glucose in the blood)
What 2 things does reduced insulin stimulate?
Hepatic glycogenolysis and gluconeogenesis
What does glycogenolysis and gluconeolysis do?
Produce glucose that is released into the blood
T/F- Lipid metabolism is also stimulated by low insulin levels causing hyperlipidemia.
Pathogenesis of Type 2 DM
-Not completely understood
-Beta cells are not damaged
-Insulin levels are normal or elevated
What is lost in type 2 DM?
Target tissue insulin receptors
-This results in a flawed response to binding of the receptors that are present
What does the target tissue insensitivity cause in Type 2 DM?
Hyperglycemia (even though insulin levels are normal or above normal)
What type of people generally have Type 2 DM?
Obese people or people with a high caloric diet
What does obesity or high calories cause?
A reduction in the number of insulin receptors on cells
What are signs and symptoms of Type 2 DM?
What occurs more, type 1 or type 2 DM?
Type 2 (90%), Type 1 (10%)
What is the clinical course for Type 1 DM?
What is the clinical course for Type 2 DM?
What is the therapy for Type 1 DM?
Insulin or diet
What is the therapy for Type 2 DM?
Diet, exercise, oral
How is glucose measured?
-Glucose oxidase (in lab or at home with test strips)
What are some errors in glucose measurements?
-Exposure of the test strips to air can cause falsely low results
-Blood glucose levels fall with elevated WBC counts and high temperatures
What is a normal parameter for fasting glucose?
What is a normal parameter for bedtime glucose?
What is a normal parameter for hemoglobin A1C?
Less than 6
What are criteria for diagnosis of diabetes?
-Random glucose greater than 200 and S and S
-Fasting glucose greater than 126 on 2 occasions
-Glucose tolerance test greater than 200 on 2 occasions
-Hemoglobin A1C greater than 6.5%
What are the parameters for impaired fasting glucose?
This is known as glycated hemoglobin or glycosylated hemoglobin
What does the hemoglobin A1C measure?
Patients blood sugar control over the past 3 months
How is hemoglobin A1C produced?
Formed when glucose in the blood binds irreversibly to hemoglobin to form a stable glycated hemoglobin complex
What is hemoglobin A1C directly related to?
Since the normal lifespan of RBC is 120 days, the HBA1C value are directly proportional to the concentration of glucose in the blood over the full lifespan of the RBC.
What is the best test to find out if the patients blood sugar is under control over time?
When are insulin levels ordered?
-To diagnose an insulinoma
-To diagnose hypoglycemia
-Identify insulin resistance
-To determine if Type II needs additional treatment with insulin or oral meds
What causes elevated insulin levels?
-Medications such as corticosteroids or OCP
-Fructose or lactose intolerance
Do these diseases increase or decrease insulin levels?
What is C-peptide used for?
Indicate whether or not a person is producing insulin or about how much
What form is insulin initially synthesized in?
What is proinsulin linked to?
Alpha and beta cells by a polypeptide called c-peptide
For 1 molecule of insulin, there is ___ molecule of c-peptide
T/F- Levels of c-peptide can be measured and used as an indicator of insulin production
What can c-peptide help access?
if high blood glucose is due to reduced insulin production or to reduced glucose intake by the cells.
Describe when c-peptide is used
-Useful marker of insulin production
-Not ordered to diagnose diabetes but can help determine how much insulin a pancreas is producing
-If patients develop antibodies to insulin, insulin levels cannot be accurately measured but c-peptide can be
-Can also be used to diagnose insulinoma as well as monitor effectiveness of treatment or recurrence
When is c-peptide ordered?
-Newly diagnosed Type 1 to evaluate if there is any residual insulin
-Type II patient where insulin is being considered as treatment
-Recurring low blood sugar
Describe a glucose tolerance test
Normal blood values for a 75-gram oral glucose tolerance test used to check for type 2 diabetes in those who are not pregnant:
What are normal parameters for fasting GTT?
What are normal parameters for I hour GTT?
less than 200 mg/dL
What are normal parameters for 2 hour GTT?
Less than 140 mg/dL
Hyperglycemia developing during pregnancy and resolving after delivery.
When are you tested for gestational diabetes?
How are you tested for gestational diabetes?
-OGTT gives pregnant woman 50 grams of glucose and a blood test after an hour
-If abnormal, will proceed to a 3 hour GGT
What should the levels of OGTT be?
less than 135
This occurs when Hyperglycemia due to other conditions such as Cushing’s syndrome, acromegaly, hyperthyroidism, medications or pancreatic destruction
What are symptoms of hyperglycemia?
What conditions lead to hypoglycemia in people with diabetes
1. Taking too much medication
2. Missing or delaying a meal
3. Eating too little food for the amount of insulin taken
4. Drinking too much alcohol