Introduction to diabetes Flashcards
where is insulin produced?
Endocrine gland of the Pancreas by beta cells the endocrine gland also secretes: -glucagon (alpha cells) -somatostatin (SS) (delta cells) -Pancreatic polypeptide (PP)
What is insulin?
an anabolic hormone
what is the role of insulin in the body?
Signals liver, muscle and fat cells to take in glucose from the blood
Sufficient energy – liver stores glucose as glycogen
Promotes storage of carbohydrate and fat and protein synthesis
How is insulin produced?
- mRNA transcript is translated into an inactive protein – preproinsulin
- Contains an amino-terminal signal sequence that is required to pass through ER membrane
- Post-translational processing removes un-needed portions
- Preproinsulin enters ER and rendered useless, is proteolytically removed to form proinsulin
- Post-translational modification and cleavage to form insulin
- Insulin packaged and stored in secretory granules which accumulate in the cytoplasm until release is triggered
How is insulin released?
(BIPHASIC RESPONSE)
- Glucose entry in to beta cells via GLUT2 transporters
- Glycolysis → ATP
- ↑ATP:ADP → depolarisation
- Opening to Ca2+ channels
- Ca2+ influx triggers exocytosis of insulin-storing granules
- Diffusion of insulin in to nearby blood vessels
define diabetes mellitus
metabolic condition that is characterised by chronic hyperglycaemia: diabetes (‘siphon’) mellitus (‘sweet’)
Outline Type 1 diabetes
- Insulin-dependent diabetes mellitus (IDDM); juvenile onset
- Destruction of pancreatic beta cells in the islets of Langerhans by the body’s own white blood cells (T cells); autoimmune disease
- Pancreas cannot produce insulin
- Regular insulin injections
- 5-10% of all diabetes
Outline Type 2 diabetes
- Non-insulin-dependent diabetes mellitus (NIDDM)
- Variable degrees of insulin resistance, impaired insulin secretion and increased glucose production
- can be controlled through diet, exercise and weight loss
- Others require oral medications and/or insulin
Risk factors for diabetes
mix of genes and enviroment some say rise in type 2 is all down to enviroment. eg.: Age Obesity Physical inactivity High blood pressure
what charachterises type 2 diabetes?
insulin resistance- less glucose in a given amount of blood compared to a control
Obesity may desensitise muscle and fat cells to effects of insulin
↓GLUT-4 translocation
identify the 4 recent hypothesis used to explain type 1 diabetes
sunshine hypothesis- ziptis and akobeng 2008
cows milk hypothesis- knip et al. 2014
hygeine hypothesis- okada et al. 2010
accelerator hypothesis- wilkin et al. 2001
what are the main symptoms of diabetes?
Polydipsia (extreme thirst) Polyuria (increased urine volume and Increased hunger Unexplained weight loss Extreme tiredness Blurred vision
what is retinopathy and what are the symptoms
(diabetic) retinopathy occurs in the eyes.
capillaries around retina blocked
blurred vision/blindness
what is nephropathy and what are the symptoms
occurs in the kidneys
fluid/waste retention
results in increased BP and kidney failure
what is Diabetic ketoacidosis
breakdown of body tissue causes: High blood glucose ketones in blood/urine nausea ketones in breath unconciousness
