Biological Basis of Diabetes Mellitus

This set of flashcards covers the biological basis, pathophysiology, symptoms, diagnosis, and complications of Diabetes Mellitus, including Types 1 and 2, DKA, and related metabolic conditions.

Diabetes

A term meaning "passing through; a large discharge of urine."

Mellitus

A term meaning "pleasant tasting, like honey."

Alpha cells

Hormone producing cells in the Islets of Langerhans that produce glucagon.

Beta cells

Hormone producing cells in the Islets of Langerhans that produce insulin.

Delta cells

Hormone producing cells in the Islets of Langerhans that produce somatostatin.

Normal random blood glucose range

$$3.5 - 8\,mmol/l$$

Normal fasting blood glucose range

$$3.5 - 5\,mmol/l$$

Glycogenolysis

The conversion of glycogen to glucose, primarily occurring in the liver.

Gluconeogenesis

The formation of glucose from non-carbohydrate sources such as fatty acids and amino acids.

Proinsulin

A small $51$ amino acid protein with $3$ disulphide bonds that is the precursor to insulin.

GLUT4

A glucose transporter protein produced by a cascade of intracellular reactions after insulin binds to its receptor.

Type 1 Diabetes Mellitus (IDDM)

A disorder characterized by autoimmune destruction of beta cells, typically commencing early in life and resulting in a lack of insulin.

Type 2 Diabetes Mellitus (NIDDM)

A progressive disorder characterized by cellular insulin resistance and decreased beta cell responsiveness to plasma glucose levels.

Polyuria

Increased urine production caused by glucose having an osmotic effect in the kidney filtrate, inhibiting water reabsorption.

Polydipsia

Increased thirst caused by dehydration from polyuria stimulating the hypothalamic thirst center.

Polyphagia

Increased food consumption with weight loss, occurring because cells utilize fat and protein stores for energy when glucose cannot enter cells.

Diabetic Ketoacidosis (DKA)

A condition resulting from insulin deficiency where increased lipolysis leads to fatty acid metabolism and elevated ketone levels, causing blood pH to drop below $7.3$.

Kussmaul breathing

A sign of DKA characterized by an increased rate and depth of respirations as the body attempts to correct acidosis.

HbA1c (Glycated Haemoglobin)

A measure of the amount of glucose attached to hemoglobin in red blood cells, providing an indication of blood glucose control over approximately $120$ days.

Non-diabetic HbA1c reference range

$$< 42\,mmol/mol$$

Gestational Diabetes

A type of diabetes occurring in $3 - 10\%$ of pregnancies, possibly due to pregnancy hormones causing insulin receptor dysfunction.

Arginine Vasopressin Deficiency (AVP-D)

Known as "tasteless diabetes," it is caused by a defect in the synthesis or release of anti-diuretic hormone (ADH).

Metabolic Syndrome

A cluster of features including central obesity, hypertriglyceridaemia, hypertension, fasting hyperglycaemia, and low High Density Lipoproteins (HDL).

Microcirculation disorders in Diabetes

Long-term complications including nephropathy (kidney damage), retinopathy (retinal damage), and neuropathy (nerve damage).

Macrovascular circulation disorders in Diabetes

Complications related to atherosclerosis, including coronary artery disease, cerebrovascular disease, and peripheral vascular disease.