Type 1 Diabetes Flashcards
What is type 1 diabetes?
Autoimmune disease. There is a loss of self-tolerance which means T-cell target the beta cell antigens.
What are the genes that cause the inappropriate immune response?
HLA DR3 and HLA DR4
What normally happens in the pancreatic beta cell?
- Glucose enter via glucose transporter
- Glucose undergoes anaerobic and aerobic metabolism to produce ATP.
- ATP bind to potassium sensitive channels, causing them to close.
- Potassioum builds up in beta cells, making it positively changed, activating voltage gated calcium channels.
- Calcium enters and stimulates vesicle that contain insulin.
What does GAD enzyme do in the pancreatic beat cells?
Converts glutamic acid into GABA. GABA is associated with insulin production and protective effects of beta cells.
3 parts that antibodies attack in pancreatic beta cells
- Specific self-antigens on pancreatic islet cells.
- GAD enzyme
- Insulin
What are the high yield antibodies that attack the islet cells antigens?
Anti-islet cell antibodies
What are the high yield antibodies that attack the GAD enzyme?
Anti-GAD antibodies
What are the antibodies that attack the insulin?
Anti-insulin antibodies
What do the antibodies do to pancreatic beta cell?
- Attack the 3 parts of the beat cells
- Destrpy beta cells. (less beta cells)
- Reduces insulin production
- Incerease blood glucose
What does insulin do to glucose normally?
- Insluin binds to insulin receptors
- Increaes expression of glucose transporters
- Glucose enters cell reducing blood glucose levels.
Thirst
- Blood volume drops as increased water and glucose lost in urine
- Gluose high and water low in the blood
- This stimulates osmoreceptors in the hypothalamus
- This triggers increased thirst
What is high glucose and low water in the blood?
Hyperosmolar blood
What is increased thirst?
Polydipsia
What causes increased glucose in the urine?
- Alot of glucose filtered into kidneys via the glomerulus filtrate
- Too much glucose to be able to be reabsorbed via the kidney tubules
- More glucose in the urine
What does more glucose in the urine do?
- Glucose osmotically active
- Pull water with it
- So lose more water via urine
Why does diabetes cause increased urine (Going to the Toilet more often)?
- Too much glucose to be able to be reabsorbed via the kidney tubule so more glucose in the urine
- Glucose osmotically active, pulls water with it
- So lose more water via urine
What is increased glucose in the urine?
Glycosuria
What is increased urine?
Polyurea
Thinner
- Decaraed glucose in cells = decreased ATP
- Uses fat and muscles for fuel, lipolysis and proteolysis
- The breakdown of fat and protein causes unexplained weight loss.
- This can also increase hunger.
4 Ts of type 1 diabetes
Toilet, Thirsty, Tired and Thinner
What does decreased glucose in cells do to ATP?
Decreased ATP
What is lipolysis?
Breakdown of triglycerides into free fatty acids and glycerol. This can be used to make ATP.
What is proteolysis?
Breakdown of protein in muscles to amino acids. This is used to make ATP.
What is polyphagia?
Increased hunger
Fasting glucose for diagnosis?
> 126mg/dl
Random glucose for diagnosis?
> 200 mg/dl
2 hour oral GGT for diagnosis?
> 200 mg/dl on 2 tests
HbA1c for diagnosis?
> 6.5%
What is a 2 hour glucose tolerance test?
Glucose given, and gluose remains high.
What is HbA1c?
Gluose in the blood likes to conjugate to the Hb, this makes a glycated Hb (Hgb). So it is a measurement of Hgb.