Control and coordination (Extended Response)

Question 1

Use the information below to explain how controlling weight could affect the occurence of Type 2 diabetes.

A chart shows the results of a survey of adults in the UK who have type 2 diabetes.
The results are grouped by BMI category for men and women:

Normal:

• men, 6.1%
• women, 2%

Overweight:

• men, 5.9%
• women, 5%

Obese:

• men, 15%
• women, 14%

Answer 1

BMI is a measure of body mass and is calculated as: mass (kg) / height (m) squared
more body fat increases BMI
18.5 to 25 kg/m[2] = normal
25 to 30 kg/m[2] = overweight
over 30 kg/m[2] = obese

people with type 2 diabetes can’t control blood glucose concentration properly
because pancreatic cells do not produce enough insulin
or muscle and liver cells do not respons to insulin

chart shows risk of developing diabetes increases as BMI increases for men and women
risk for women increases more rapidly than for men above a BMI of about 27

if people control weight and don’t develop a high BMI, the risk of type 2 diabetes stays low
this beneficial effect is greater for women than for men

chart shows men and women in UK only
conclusion may not apply to people in other countries, or other ethnic groups, or for other variables such as exercise or diet

Question 2

Explain how blood glucose concentration is regulated in a healthy person.

Answer 2

blood glucose concentration rises after absorbing glucose from digested meal

blood glucose concentration falls as glucose is taken from blood by cells for respiration or storage

as bgc rises, cells in pancreas respond by releasing the hormone insulin into the blood

insulin causes cells to take up more glucose

liver and muscle cells store extra glucose as glycogen

when bgc falls too low, other cells in pancreas respond by releasing hormone glucagon into blood

glucagon causes liver cells to break down glycogen into glucose and release it into the blood

bgc kept within limits, which is homeostasis

control of bgc shows negative feedback as a change in one direction causes a change in the opposite direction to happen