Term
| What are the three primary cells that make up the Islet's of Langerhans and what hormones/proteins do they secrete? |
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Definition
-Alpha cells secrete gulucagon
-Beta cells secrete insulin
-Delta cells secrete somatostatin |
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Term
| In addition to the rise in blood glucose, what other four events stimulate the release of insulun? |
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Definition
-Amino acids as a result of ingestion of a protein
-Fatty acids, sadly, a food very plentiful in most American meals
-Gastrointestinal hormones: In response to the presence of food inside it, the GI track secretes a number of hormones (e.g., gastric inhibitory polypeptide) that act to coordinate the digestion of food-one of their actions is to stimulate insulin secretion
-Parasympathetic or Vagal action: the islets of Langerhans are subject to vagal stimulation prior to and during the process of digestion, resulting in the release of insulin. |
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Term
| Describe the normal response of blood levels of glucose, insulin, and glucagon to an oral glucose tolerance test (OGTT). |
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Definition
Fasting: blood b/w 60-110 mg/dl
Insulin goes up, gloucose goes down
Insulin goes up, gluacon goes down
2 hours post: Blood should be <140 mg/dl-normal
above >140-prediabetic |
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Term
| Explain the four steps that occur in the beta cell release of insulin. Besides glucose, what other nutrients will stimulate this same response? |
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Definition
Four steps:
1) Glucose transported into beta cell by facilitated diffusion through a glucose transport protien-2 (GLUT2)
2) Entrance of glucose activities production of ATP, which closes potassium channels (K+ channels), thus depolarizing the cell
3) Deporization of cell opens voltage-gated calcium channels, and Ca++ enters the cell
4) Entrance of Ca++ triggers exocytosis of insulin-containing secretory granules
Other nutrients:
-Fats (fatty acids)
-Proteins |
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Term
What are the three target cells (i.e., tissues) of insulin and what are the actions of insulin at each tissue? Why is Insulin called an “anabolic hormone”?
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Definition
Look at pic
-Anabolic hormones stimulate growth, mineralization of bone, and growth of muscle mass by constructing molecules from smaller unites. In the case of insulin, it stimulates the formation of glycogen from glucose, triglycerides from glucose and fatty acids, and protein from amino acids |
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Term
What are the cellular action of insulin at the target cell (include insulin receptors and GLUT4 in your answer).
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Definition
-Stimulation of th insulin receptor will up regulate, from an intracelluar pool, glucose transport protein-4 (GLUT4)
-Up regulation of GLUT4 allows the entrance of glucose into the cell. |
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Term
In the “Fed State”, what factors inhibit the release of glucagon from the alpha cells?
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Definition
-Release insulin and amylin from the beta cells-these two molecules inhibit the release of glucagon from the alpha cells
-Entrance of glucose into the alpha cells |
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Term
In the “Fasting State”, what three factors allow for the release of glucagon from the alpha cell?
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Definition
-There is little to no release of insulin and amylin by beta cells
-Removal of the inhibitory effect that glucose entry into the alpha cells has |
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Term
What effect does glucagon have on the liver’s glycogen (what is the term for this)? What effect does this have on blood sugar?
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Definition
-Stimulates the liver to convert amino acids into glucose (i.e. glycongenolysis) and release glucose into the blood
-Increases blood glucose |
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Term
What effect does glucagon have on the liver in terms of its handling of amino acids (what is the term for this)? What effects does this have on blood sugar?
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Definition
-Stimulates the liver to convert amino acids into glucose (i.e. gluconeogenesis)
-Increases blood glucose |
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Term
What effect does glucagon have on fat cells (what is the term for this)? What is the fate of fatty acids in the liver (what is the term for this)? What effect does this have on blood levels of ketones?
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Definition
-Stimulates fat cells to break down triglycerides to ketones and fatty acids (lipolysis) and the fatty acids released into the blood. Fatty acids are taken up by the liver are converted to ketones (ketogenesis)
-Liver releases ketones into the blood and therfore, increase blood levels of ketones |
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Term
What are the three types of diabetes studied in this course? Which one is identified with autoimmune destruction of the beta cells? Insulin insensitivity? Pregnancy?
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Definition
-Type 1, Type 2, and gestational diabetes
-Type 1 is identified with autoimmune distruction of the beta cells
-Type 2 is related to insulin insensitivity (also called insulin resistance)
-Gestational diabetes, which is considered a type 2 during pregnancy b/c it is also associated w/insulin resistance |
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Term
What are the terms “childhood diabetes”, “adult onset diabetes”, “insulin independent diabetes” misnomers?
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Definition
-Type 1 an also occur in middle age or in the elderly, thus "childhood diabetes" is a misnomer
-Type 2 diabetes is occuring in adolescents (i.e., due to obesity epidemic), thus "adult onset diabetes" is a misnomer
-Insulin becomes a treatment in the latter states of type 2 diabetes, thus "insulin dependent" is a misnomer |
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Term
What is the usual age range for the onset of type 1 diabetes?
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Definition
| The onset of type 1 diabetes across genders is usually in childhood or adolescence, w/peak onset in early adolescents. |
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Term
When considering the time line of type 1 diabetes, what is meant by “silent Beta cell loss”?
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Definition
| Although the immune system is destroying beta cells, it is called "silent beta cell loss" b/c no symptoms have become apparent. |
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Term
In type 1 diabetes, by the time symptoms are demonstrated, what percentage of functional islet cell loss has occurred?
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Definition
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Term
In type 1 diabetes, what two conditions cause diuresis? What do the terms polyuria and polydipsia mean?
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Definition
-High blood glucose and ketone levels spill over into the urine, takin water and solutes along with them in a process known as osmotic diuresis
-Osmotic diuresis leads to excess production of urine (i.e., polyuria). Polyuria causes dehydration resulting in excessive thirst (polydipsia)
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Term
In type 1 diabetes, what four symptoms are caused by Ketoacidosis?
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Definition
| Symptoms due to ketacidosis are abdominal pains, vomiting, mental confusion, and hyperventilation |
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Term
What are the three characteristics of type 2 diabetes?
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Definition
Type 2 diabetes is characterized by:
-insulin resistance (i.e. higher than normal levels of insulin are needed to control blood glucose levels)
-Relative insulin deficiency (i.e. the beta cells become "exhausted" and cannot produce sufficient amounts of insulin to control blood sugar levels)
-Hyperglycemia-chronic high blood glucose levels due to insulin resistance and insulin deficiency |
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Term
What are the two metabolic defects that characterize type 2 diabetes?
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Definition
Basically, this question is meant to identify the metabolic defects that cause the three characteristics identified in question #19. The two metabolic defects are:
-Derangement of beta-cell secretion to insulin (i.e. relative insulin deficiency)
-An inability of peripheral tissues to respond to insulin (or insulin resistance)/as with the vast majority of diseases we have addressed in this course, there is a genetic component and and environmental component. The genetic component (i.e., "loads the gun") of type 2 diabetes the derangement of beta-cell secretion of insulin. The environmental component (i.e. "pulls the trigger") is the peripheral insulin resistance. The latter is controlled by lifestyle. |
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Term
What would be normal prediabetic and diabetic readings for a fasting plasma glucose test?
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Definition
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Term
What would be normal prediabetic and diabetic readings for an oral glucose tolerance test?
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Definition
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Term
It is said that fasting plasma glucose test and the oral glucose tolerance test gives you a “snap shot” of a persons blood glucose whereas a glycated hemoglobin (glycosylated)hemoglobin (HbA1c) gives a clinician a “bigger pictures” of a patient’s blood glucose levels. Explain.
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Definition
| Glycated hemoglobin is a form of hemoglobin used primarily to identify the average plasma glucose concentration over prolonged periods of time (i.e., 60-90 days). This serves as a marker for average blood glucose levels over the previous months prior to the measurement (e.g., using the fasting plasma glucose test). |
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Term
What percent levels of HbA1c could be considered healthy, when a patient is “at risk” developing type 2 diabetes, and when it is considered a diagnosis for diabetes? Identify the name given to areas of the body for major diabetic complications: eyes, brain, kidney, heart, lower limbs, peripheral nervous system, and foot.
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Definition
For HbA1c:
-≤ 5.6%: considered "good" or in the healthy range
-5.7-6.5%: at risk for developing diabetes
->6.5%: diagnosis for diabetes |
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Term
How can the complications in question #25 be controlled or prevented?
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Definition
| Strict conrol of the hyperglycemia through medications and lifestyle |
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Term
What are diabetogenic hormones and where are they produced during pregnancy?
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Definition
| Diabetogenic hormones are hormones that block the action of insulin and they are procuced by the placenta |
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Term
In gestational diabetes, what trimester do symptoms begin to appear?
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Definition
| During the third trimester the diabetogenic hormones produced by the placenta peak, glucose levels are elevated and diabetic symptoms begin to appear. |
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Term
Differentiate between foods with a high or low glycemic index (GI) in terms of speed at which glucose is released into the blood and insulin demand. What types should a type 2 diabetic consume to help control his/her blood sugar level (i.e., high or low)?
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Definition
-Carbohydrates that break down quickly during digestion and release glucose rapidly into the bloodstream have a high GI
-A person whose diet consists of mostly foods in the low glycemic index usually equates to a lower insulin demand and improved long-term blood glucose |
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Term
Identify the name given to areas of the body for major diabetic complications: eyes, brain, kidney, heart, lower limbs, peripheral nervous system, and foot.
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Definition
-Eyes (retinopathy)
-Brain and cerebral circulation (CVD)
-Heart and coronary circulation (CHD)
-Kidney (Nephropathy)
-Lower limbs (PVD)
-Peripheral nervous system (neuropathy)
-Diabetic foot (Ulceration and amputation) |
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