Insulin Levels and Diabetes

Question 1

What do the membranes of the beta cells have?

Answer 1

calcium (normally closed) and potassium (normally open) ion channels, K+ flow out, inside of cell more negative, at resting potential = -70mV

Question 2

What happen to beta cells when glucose concentrations outside the cell are high?

Answer 2

glucose mols diffuse into cells, glucose quickly used in metabolism to produce ATP, extra ATP causes K+ channels to close

Question 3

What happens when the potassium ion channels in the beta cells are closed?

Answer 3

K+ cant diffuse out and potential difference is altered, less negative inside, change = calcium channels open

Question 4

What happens when the calcium ion channels in the beta cells are open?

Answer 4

calcium ions enter the cell and cause the secretion of insulin by making vesicles containing insulin move to the cell membrane and fuse with it, then exocytosis

Question 5

What is diabetes mellitus?

Answer 5

disease where blood glucose concentrations cant be controlled effectively

Question 6

What is hyperglycaemia?

Answer 6

state in which the blood glucose concentration is too high

Question 7

When do blood glucose concentrations rise and fall?

Answer 7

after meal rises, during exercise falls

Question 8

What is hypoglycaemia?

Answer 8

state in which blood glucose concentration is too low

Question 9

What is Type 1 diabetes?

Answer 9

insulin dependent, often juvenile onset, result of autoimmune response where body attacks own beta cells, or from viral attack, body doesn’t manufacture enough insulin cant store excess glucose and glycogen

Question 10

What is type II diabetes?

Answer 10

non-insulin dependent, insulin still produces but with age response to insulin decreases, receptor number and insulin production declines

Question 11

What 4 factors bring on early onset of type II diabetes?

Answer 11

obesity, diet high in sugars (esp refined), being Asian or Afro-Caribbean, family history

Question 12

How is type II diabetes treated?

Answer 12

careful monitoring of diet, carbohydrate intake and use is matched, eventually supplemented by insulin injection or other drug use which slow glucose absorption

Question 13

How is type I diabetes treated?

Answer 13

insulin injections, the blood glucose concentration is monitored and correct dose administered

Question 14

What has recent research shown about diabetes treatment?

Answer 14

stem cells, precursor cells in pancreas of adult mice, cells capable of developing into variety of cells, if similar ones can be found to human pancreas then new treatment

Question 15

How did insulin used to be produced for treatment?

Answer 15

extracted from pancreas of animals, usually from the pigs as this matches humans most closely

Question 16

What is the more recent method of insulin production for treatment?

Answer 16

produced by bacteria that have been genetically engineered to manufacture human insulin

Question 17

What are the advantages of using insulin from genetically modified bacteria?

Answer 17

exact copy of human insulin, less chance of developing tolerance or rejection, lower infection risk, cheaper, process more adaptable to demand, less moral objections