Diabetes Flashcards
What is the role of insulin?
It is released in response to food intake, signalling the body to utilise or store glucose
How does insulin work?
Insulin binds to specific receptor sites on cells, triggering a cascade of signalling pathways that regulate glucose metabolism - this is known as the insulin signal transduction pathway, this pathway activates various enzymes and transcription factors that regulate glucose and lipid metabolism within the cell.
How do glucose and insulin interact?
The binding of insulin to its receptor causes the receptor to autophosphorylate, recruiting and activating other signalling molecules. This leads to the translocation of glucose transporter proteins to the cell membrane, facilitating the uptake of glucose into the cell.
Where is glucagon produced?
The pancreas
What is the role of glucagon?
Plays a crucial role in regulating blood glucose levels.
When is glucagon released and what happens when it is?
When the body lacks food glucagon is released - it binds to receptor sites and triggers the liver to break down glycogen and release glucose into the bloodstream. Glucose also stimulates the breakdown of stored fat (triglycerides) in adipose tissue into fatty acids and glycerol, providing an alternative energy source when glucose is scarce. The glycerol is then taken up by the liver and converted into glucose, the fatty acids can be used by the liver to produce ketone bodies which also provide an alternative energy source. This helps maintain blood sugar levels and prevent hypoglycaemia during periods of fasting or starvation
What is gluconeogenisis?
When glucose is produced from non-carbohydrate precursors
What happens when things go wrong?
Insulin resistance - in type 2 diabetes when the body’s cells become resistant to the effects of insulin
Autoimmune destruction - in autoimmune diseases the body’s immune system mistakenly attacks and destroys the insulin, producing beta cells in the pancreas
Insulin deficiency - leads to a reduction in insulin secretion, resulting in a state of absolute insulin deficiency - characteristic of type 1 diabetes
What happens in type 2 diabetes mellitus?
- The body’s cells become resistant to insulin, leading to impaired glucose intake
- The pancreas is unable to produce enough insulin to overcome the resistance, leading to impaired glucose regulation
- The blood glucose levels rise higher than normal
What is diabetes insipidus?
A rare condition characterised by excessive thirst and frequent urination, it is caused by a deficiency in ADH
What are the 2 types of diabetes insidious?
central and nephrogrenic
What is central diabetes insipidus caused by?
A lack of ADH production in the hypothalamus or pituitary gland
What is nephrogenic diabetes insipidus caused by?
The kidneys’ inability to respond to ADH
What is lean type 2 diabetes mellitus?
- The key risk factor is having fat around the organs leading to organ failure and beta cell dysfunction
- Individuals with a lean body type can still develop insulin resistance and type 2 diabetes if they have visceral fat deposits around organs
- The build up of visceral fat can impair pancreatic beta cell function leading too reduced insulin production and the development of type 2 diabetes
What is gestational diabetes?
Diabetes that develops during pregnancy
What is gestational diabetes caused by?
Hormones made by the placenta that prevent the body from effectively using insulin - this insulin resistance leads to high blood glucose levels which can have serious implications for the mother and developing m=baby
What happens in the progression of gestational diabetes as the placenta increases in size?
The level of hormones such as oestrogen, progesterone and human placental lactose rise, this can lead to greater insulin resistance raising the risk of developing gestational diabetes
