Lecture 4: Calcium Homeostasis Flashcards
What are the example hormonal regulators of fuel metabolism and their brief function and location
Insulin: released when blood glucose is high.
Glucagon: released from the pancreas when blood glucose is low.
Epinephrine: released from the adrenal medulla in response to need for activity.
Cortisol: released from the adrenal cortex in response to stress.
Diagram of glucose regulation
Lecture notes
What is the effect of insulin
facilitates entry of glucose into muscle, adipose and several other tissues.
stimulates the liver to store glucose in the form of glycogen.
What is the effect of glucagon
Stimulating the liver to break down glycogen to be released into the blood as glucose.
Activating gluconeogenesis, the conversion of amino acids into glucose.
Breaking down stored fat (triglycerides) into fatty acids for use as fuel by cells.
What are the counter regulatory hormones and what is their function
Cortisol: mobilizes reserves from adipose tissue, causes muscle protein breakdown and stimulates gluconeogenesis in liver.
Growth Hormone (GH) is secreted from the anterior pituitary and has an anti-insulin effect it inhibits the insulin-mediated cell uptake of glucose. Its overall effect is to raise blood glucose and FFA levels. GH secretion is stimulated by hypoglycaemia and inhibited by hyperglycaemia.
Epinephrine: released from the adrenal medulla in response to need for activity.
What is a counter regulatory horomone?
work against the action of insulin, raising blood glucose levels in response to hypoglycemia (low blood sugar).
What is the types of diabetes and brief description
Type 1: Due to not enough insulin being made in the pancreas
Type 2: Due to insulin resistance on insulin receptors on cells, so glucose cant enter
Gestational: pregnancy
Compare Type 1 and Type 2 diabetes
Type 1: Onset: Sudden Age of onset: Child Body Size: Normal Ketoacidosis: Common Autoantiobodies: Yes Endogenous Insuin: Low/absent Identical twins: 50% Prevalance: 10%
Type 2: Onset: Gradual Age of onset: Adult Body Size: Obese Ketoacidosis: Rare Autoantiobodies: No Endogenous Insuin: Normal, decreased or increased Identical twins: 90% Prevalance: 90%
How is diabetes diagnosed in the lab?
Fasting plasma glucose ≥126 mg/dL (7.0 mmol/L) (Fasting is defined as no caloric intake for at least 8 hours)
Symptoms of DM and a casual plasma glucose ≥200 mg/dL (11.1 mmol/L) (Casual is defined as any time of day without regard to time since last meal)
Classic symptoms of diabetes include polyuria, polydipsia, and unexplained weight loss
2-hour plasma glucose ≥200 mg/dL (11.1 mmol/L) during oral glucose tolerance test (OGTT)
HbA1c ≥6.5%
What are the 3 main ways that the body gets sugar
- Intestinal absorption from food
- Gluconeogenesis from liver
- Glycogen breakdown
What is the role of insulin
It can inhibit the breakdown of glycogen or the process of gluconeogenesis.
It can stimulate the transport of glucose into fat and muscle cells.
It can stimulate the storage of glucose in the form of glycogen
Pathophysiology flow diagram for metabolic acidosis
If the amount of insulin available is insufficient
If cells respond poorly to the effects of insulin
If the insulin itself is defective
Then glucose will not be absorbed properly by the body cells
The net effect is persistently high levels of blood glucose, poor protein synthesis, and break down of fat storage
Metabolic acidosis
Why does metabolic acidosis occur in diabetics?
When you have diabetes and don’t get enough insulin and get dehydrated, your body burns fat instead of carbs as fuel.
Breaking down fatty acids produces ketones bodies (Beta-hydroxybutyrate), which can make your blood acidic.
Why does electrolyte inbalance occur in diabetics?
High blood sugar causes excessive urination and spillage of sugar into the urine.
This leads to loss of body water and dehydration as well as loss of important electrolytes, including sodium and potassium.
The level of another electrolyte, bicarbonate, also falls as the body tries to compensate for excessively acidic blood.
Why does osmotic diuresis occur in diabetics
The primary cause of osmotic diuresis is an elevated blood glucose (hyperglycemia) which is sometimes the result of poorly controlled diabetes.
When there is excess glucose in the blood, and it passes through the kidneys for filtering, the excess glucose accumulates in the tubules within the kidneys- volume depletion and dehydration
Once there, it blocks the reabsorption of water, leading to an increased concentration of water in the bloodstream.
The kidneys then act to remove the excess water, causing increased urine production and increased frequency in urination.
