Blood Glucose

• You have one minute to write down everything you can know about glucose and it’s uses

Blood glucose• Glucose test

Blood glucose control

• Blood glucose is controlled by hormones.

• Hormones are:– Always produced by glands and secreted directly

into the blood– Carried in the blood plasma to the cells on which

they act which have receptors complementary to the hormone

– Have widespread and long lasting effects

Blood Glucose Control

• Pancreas is a large pale coloured gland

• It produces enzymes (protease, lipase and amylase)

• And Hormones (insulin and glucagon)

Blood Glucose Control

• Most of the pancreas makes enzymes for digestion but scattered throughout these cells are hormone producing cells – islets of Langerhans

Blood glucose control

• You DON’T need to know about DELTA cells (somatostatin, growth-hormone-inhibiting hormone)

Blood Glucose Control

• Normal blood glucose is 90mg per 100cm3 of blood

• Where does blood glucose come from?

Blood Glucose control

• Directly from the diet • Break down of glycogen – GLYCOGENOLYSIS• GLUCONEOGENESIS – making glucose from

sources other than carbohydrates, the liver can make glucose from glycerol and amino acids

Blood glucose control• To do…BLIND SEQUENCING• Tallest person is dealer• When you get your cards write your initials on the back

of your card – don’t show them to anyone else!• In your groups of three number yourselves 1,2 or 3• Number…go first. • Read what is on your card then put it face down on the

table• Move clockwise around the group • Your task is to produce a feedback loop for blood

glucose regulation WITHOUT looking at anyones cards but your own.

Blood Glucose Control

• β cells detect a rise in blood glucose• β cells secrete insulin directly into the blood

plasma• Insulin is a globular protein made up of 51

amino acids• Almost all body cells have glycoprotein

receptors on their cell surface membrane that bind with insulin molecules

Blood glucose control• When insulin combines with the receptors,

insulin brings about:– A change in the tertiary structure of glucose

transport protein channels, causing them to change shape and open, allowing more glucose into the cells

– An increase in the number of carrier molecules in the cell surface membrane

– Activation of the enzymes that convert glucose to glycogen and fat

Blood Glucose Control

• α cells of the islets of Langerhans detect a fall in blood glucose concentration

• Α cells secrete glucagon directly into the blood plasma

• Glucagon travels in the blood to receptors in the liver cells

Blood glucose control

• Glucagon causes liver cells to:– Activate an enzyme that converts glycogen to

glucose– Increases the conversion of amino acids and

glycerol to glucose (gluconeogensis)• The amount of glucose in the blood returns to

normal

Blood Glucose Control

• Glucagon is not the only hormone that stimulates the break down of glycogen in the liver

• Adrenaline also has an affect and it does this using the second messenger system (glucagon also uses this system!)

Second messenger model• Hormone (Adrenaline) is the 1st messenger – it binds to

receptors on the cell-surface membrane of target cells (Liver) to form a hormone-receptor complex

• The hormone receptor complex activates an enzyme inside of the plasma membrane

• This enzyme acts on ATP• The enzyme produces cyclic AMP (removing two of the

phosphate groups) cAMP• cAMP is the second messenger and activates other

enzymes that carry out the breakdown of glycogen to glucose

• Draw a series of diagrams to summarise this

Summary time

• Draw a cartoon (with characters and everything) to show how blood glucose levels are regulated

Blood Glucose control

• What can you remember from yesterdays lesson?

• Draw a five minute poster to summarise it!

Diabetes• What can you remember about diabetes –

write it on your post it note and stick it on the board.

• Diabetes

diabetes• Diabetes is a condition where the homeostatic

control of blood glucose breaks down

• 2 million people in the UK suffer from diabetes and the numbers are growing – why?

diabetes

• Home and Away

• In your pair you have been given either TYPE I or TYPE II diabetes

• Your job is to read through the information and SUMMARISE it for your partner.

Type I vs II diabetes

• Draw a venn diagram to compare the different types of diabetes.

Diabetes

• Blood glucose tests – lets test some different samples and see if you can spot:– The normal person– The person with Diabetes– The person with kidney disease– The person who is dehydrated.