2.8- blood glucose levels and obesity Flashcards
what is the usual concentration of glucose in blood plasma and what can alter this?
5 millimoles per litre
depending on demand from varying tissues
what can blood glucose levels raise to for a person with diabetes?
30mmol/l
10/30
what happens during chronic elevation and what does it cause?
endothelial cells lining blood vessels absorb far more glucose than normal
causes damage to blood vessels
what may develop due to chronic elevation and what 3 conditions could this lead to?
atherosclerosis
peripheral vascular disease, CVD or stroke
3 steps in microvascular disease
endothelial cells lining a small blood vessel take in more glucose than normal
endothelial cells may lose their strength and burst and bleed into surrounding tissues
leakage reduces blood flow through the body and it doesn’t receive an adequate oxygen supply
3 areas microvascular disease causes damage to and how
retina- affecting vision
kidneys- causing renal failure
nerves in extremities- causing peripheral nerve dysfunction
what are the bodys requirements and how does it guarantee they are met?
regular supply of glucose to be present in the bloodstream
body employs a system of negative feedback control known as homeostasis
5 steps in the body’s response to an increase in blood glucose
receptor cells in the pancreas detect a rise in blood glucose concentration
receptor cells trigger increased secretion of insulin
insulin travels in bloodstream from pancreas to liver where insulin receptors pick it up
excess glucose absorbed by liver cells
enzyme activated to catalyse reaction of glucose to glycogen
5 steps in the body’s response to a decrease in blood glucose
different receptor cells in the pancreas detect a drop in blood glucose concentration
receptor cells trigger increased secretion of glucagon which is transported to the liver
different enzyme activated to catalyse reaction of glycogen to glucose
glucose released from liver cells, returning the concentration to normal
around 100g of glucose stored as glycogen in the liver
when does the body need additional supplies of glucose and why?
during exercise or the fight/flight response
provide energy quickly
what is released and from where when the body needs energy quickly?
adrenal glands secrete increased quantity of adrenaline into bloodstream
3 steps in adrenalines effect on the body
overrides normal homeostatic control of blood glucose level by inhibiting the secretion of insulin and stimulating glucagon secretion
this promotes breakdown of glycogen to glucose
adrenaline reduced to a minimum and blood glucose returns to normal when crisis over
what are people with diabetes unable to do?
control their own blood glucose level
3 characteristics of diabetes type 1
usually occurs in childhood
unable to produce insulin
treatment is regular doses of insulin
3 characteristics of diabetes type 2
usually develops in later life
likelihood is increased by being overweight
insulin is produced but cells are less sensitive
what causes the insulin resistance in type 2 diabetes and what does it lead to?
the decrease in the number of insulin receptors in the liver
leads to a failure in the conversion of glucose to glycogen
what happens in both types of diabetes if left untreated?
results in a rapid increase in blood glucose level following a meal
what happens to some of the excess glucose in untreated diabetics?
kidneys remove it which results in glucose appearing in the urine
what can be used as an indicator of diabetes?
testing urine for glucose
what is glucose tolerance and what does it depend on?
the capacity of the body to deal with ingested glucose
depends on the body being able to produce adequate quantities of insulin
2 steps in the glucose tolerance test
blood glucose concentrations of the individual are initially measured after fasting
individual then drinks a glucose solution and changes in their blood glucose concentration are measured for at least 2 hours
3 differences between a diabetic and non-diabetics blood glucose concentration during the glucose tolerance test
diabetic blood glucose concentration usually starts at a higher levels than a non-diabetic
diabetic blood glucose concentration increases to a much higher level
diabetic blood glucose concentration takes longer to return to its starting concentration
what is obesity characterised by?
the accumulation of excess body fat in relation to lean tissue such as muscle
2 conditions an individual becomes at risk for when obese
cardiovascular disease
type 2 diabetes
how is body mass index calculated?
body mass (kg) ÷ height² (m²)
what must a BMI be over to indicate obesity?
30+
what is the downside of BMIs?
can wrongly classify muscular individuals as obese
what do different BMI values indicate?
20-25 —> ideal for height
26-30 —> overweight
31-40 —> obese
40+ —> very obese
5 factors thought to contribute to obesity
genetic
psychological
environmental
metabolic
dietary
2 of the most common causes of obesity
excessive consumption of food rich in fats and free sugars
lack of physical activity
why should the energy intake in a diet limit fats and free sugars?
fats have a high calorific value per gram
free sugars require no metabolic energy to be expended in their digestion
what is the main treatment for obesity?
reduction in energy intake and an increase in energy expenditure
2 reasons why exercise is beneficial as a treatment for obesity
increases energy expenditure
preserves lean tissue
what does exercise help to reduce and what’s 4 ways it does this?
helps to reduce risk factors for CVD
keeps weight under control
minimises stress
reduces hypertension
improves blood lipid profiles
