Glucose Regulation Review for Quiz #2 Flashcards
(105 cards)
What is diabetes?
A group of conditions characterized by a high level of blood glucose / blood sugar
What are the different types of diabetes?
Type 1 DM
Type 2 DM
Gestational, diabetes
Pre-diabetes
Type 1 DM definition
Beta cells of the pancreas are destroyed by the immune system by mistake; genetic factors play a role
Insulin production is reduced; less insulin binds to receptors on target cells, which means that less glucose is taken into the cells and more glucose in the blood
What is type 1 DM characterized by?
Early onset, symptoms start suddenly, before the age of 20
INSULIN DEPENDENT
Type 2 DM definition
Pancreas produces enough insulin, but something goes wrong with receptor binding/insulin signaling inside the target cells
The cells are not responsible for insulin, and cannot import glucose
What is type 2 DM characterized by?
Adult onset; symptoms are gradual after age 30
INSULIN RESISTANT
Gestational diabetes
Acquired during pregnancy, and usually resolves after giving birth
Usually occurs in third trimester
Cause is thought to be related to pregnancy hormones that interfere with insulin’s action on insulin receptors
Pre-diabetes
Blood sugar level is at the border line; higher than normal, but lower than diabetics
May or may not progress to diabetes
Insulin
A hormone secreted by beta cells in the center of the Islets of Langerhans that is necessary for glucose intake by target cells
Islets of Langerhans
Clusters of cells in the pancreas that produce hormones of insulin and glucagon
Glucagon
Secreted by alpha cells in the periphery of the Islets of Langerhans
What is the physiology of insulin?
It REDUCES blood glucose levels by binding to insulin receptors embedded in the cell membrane of various insulin-responsive tissues, like muscle cells and adipose tissue
What is the physiology of glucagon?
It RAISES blood glucose levels by getting the liver to generate new molecules of glucose from other molecules, and also break down glycogen into glucose to get dumped into the blood
What is the physiology of Type 1 DM?
Autoimmune destruction that cannot be prevented
The body cannot make enough insulin because of a Type IV hypersensitivity response/cell-mediated immune response
What happens in the Type IV hypersensitivity response / cell mediated immune response in Type 1 DM?
A persons own T cells (part of the immune system) attack the pancreas
This is a genetic abnormality that causes a loss of self tolerance among T cells, which specifically target the beta cell antigens
What are T cells?
Cells that react to antigens (usually small peptides—polysaccharides or lipids; some of the antigens are part of our body cells)
Antigens are foreign substances that induces an immune response in the body
What is self tolerance?
A process the body uses to eliminate T cells
What does losing self tolerance mean?
It means that T cells are allowed to recruit other immune cells and coordinate an attack on the beta cells
What does losing beta cells mean?
Losing beta cells = less insulin = glucose overload in the blood
What is the Human Leukocyte Antigen (HLA) system?
Where a group of genes on chromosome 6 encode the Major Histocompatibility Complex (MHC) — a protein that is important for helping the immune system recognize foreign molecules in maintaining self tolerance
People with type one DM have specific HLA genes in common with each other
What is the genetic clue for Type 1 DM?
HLA – DR3
HLA – DR4
*Note that not everyone with those genes develop diabetes
What are the symptoms of Type 1 DM?
Beta cell destruction starts early and usually 90% of the cells are destroyed before symptoms start to appear
Polyphagia, glycosuria, polyuria, polydipsia,
What is the treatment for type 1 DM?
Lifelong insulin therapy to regulate blood glucose levels and enable cells to use glucose
What is polyphagia?
Extreme hunger
Phagia = eating; poly = a lot