Topic 9- Insulin and Diabetes Flashcards
Define diabetes mellitus
metabolic disorder characterised by abnormal chemical reactions that alter normal metabolic processes
Define diabetes
a disease that causes polyuria, glucosuria, polyphagia, polydipsia
What is diabetes insipidus?
characterised by abnormal secretions of ADH
What is insulin?
secreted from B cells of the Islets of Langerhans in the pancreas, in response to increased blood glucose level
What are the two main glucose transporters and what do they do?
GLUT 2: bidirectional flow in the liver, pancreas and renal tubules (all these organs need bidirectional flow of glucose)
GLUT 4: one-directional, skeletal muscles and adipose tissue
Glycogenesis
glucose –> glycogen
Lipogenesis
glucose –> triglycerides
Glycogenolysis
glycogen –> glucose
Gluconeogenesis
glucose from non-carb sources
Lipolysis
triglyceride breakdown
What is glucagon/
secreted from alpha cells in the Islets of Langerhans in the pancreas in response to low blood glucose levels
What are ketone bodies?
resulting from no glucose breakdown during ATP production - fatty acids cannot enter the kreb’s cycle without glucose so instead they are sent to the liver where ketones are produced as energy
Why are ketones harmful in high levels?
makes blood acidic
What occurs in a fed state?
increased insulin, decreased glucagon
increased: lipogenesis, glycogenesis, protein synthesis
decreased: glycogenolysis, gluconeogenesis, lipolysis, ketogenesis
What occurs in a fasted or starved state?
increased glucagon, decreased insulin
decreased: lipogenesis, glycogenesis, protein synthesis
increased: glycogenolysis, gluconeogenesis, lipolysis, ketogenesis
What kind of inflammation is diabetes?
stress response or para-inflammation
What is type 1 diabetes?
catabolic disorder characterised by:
- lack of insulin
- B cell destruction
- elevated BGL (hyperglycaemia)
- increased fat/protein breakdown
- at the level of the pancreas
What is the difference between type 1A and 1B?
1A: immune-mediated destructionof beta cells by T cells
1B: idiopathic, no immune component
What is type 2 diabetes?
insulin resistance caused by:
- genetic predisposition
- obesity
- certain ethnicities
What occurs to cells over time due to hyperglycaemia?
hypotrophy, hypoplasia, apoptosis, glucose toxicity, lipotoxicity
How are diabetes and obesity related?
obesity puts the body in a pro-inflammatory state
insulin usually suppresses inflammatory mediators, but insulin resistance = increased inflammation
polyphagia
excessive hunger
polyuria
excessive urination
polydipsia
excessive thirst
glucosuria
glucose in urine
Treatment for type 1?
lifelong insulin injection
Treatment for type 2?
diet and exercise modifications
How is diabetes detected?
fasting blood glucose levels, oral blood glucose, glycated haemoglobin test
Fasting blood glucose levels
normal: less than 5.5mmol/
DM: more than 7.7mmol/L
OGTT (oral blood glucose test) levels
normal: less than 7.8mmol/L
DM: 11.1 mmol/l
Glycated haemoglobin levels
normal: less than 6.5%
DM: greater than 6.5%
Casual BGT levels
normal: less than 11.1mmol/L
DM: greater than 11.1mmol/l
What is pre-diabetes?
can be reversed
elevated BGL but not in range of DMT2
early detection and changes can prevent onset of DMT2
Acute complications of hypoglycaemia?
- failure to eat
- incorrect insulin doage
- increased exercise
- excessive alcohol
- altered cerebal functions: headache, disturbed behaviour
- ANS changes: anxiety, sweating, cool clammy skin
Chronic complications of diabetes?
macrovascular, microvascular, neurophaties,
Macrovascular
cerebral vascular, coronoary artery, peripheral vascular, atherosclerosis, stroke, HBP
Microvascular
nephropathies, retinopathies
Neuropathies
somatic, autonomic
What are some other complications of diabetes?
- thickening of basement membrane - hypoxia
- glycostation - protein and glucose accumulating in vessels
- damaged cells - glucose –> sorbitol = increased pressure/water influx
- damaged myelin - impaired nerve transmission
What occurs in retinopathies?
damage to blood vessels, cataracts
What occurs in nephropathies?
-basement membrane thickening –> efferent and afferent arterioles, glomeruli, Bowman’s capsule, nodular lesions, glomerulosclerosis
What occurs in neuropathies?
- ischaemia to nerves
- damage to myelin = slow impulses
- decreased ability to empty bladder, cardiac response, vasomotor function
Foot uclers
- decreased blood supply and nerve damage
- decreased pain = decreased sensory information –> unnoticed ulcers
- poor circulation and immune function –> poor healing: infections, gangrene, amputations
