Nutrients & Homeostasis

Metabolism & Body Heat Metabolism –All of the chemical reactions of the body taken together If rxns happen fast  fast metabolism –These people use the energy in food (measured in calories) more quickly Most adults need between calories per day Exercise  use more calories  give off more heat Nervous  use more calories  give off more heat

Nutrients & Homeostasis Your body needs a constant supply of energy, but you don’t eat constantly Certain organs regulate the amount of nutrients in the blood

Liver Takes glucose (direct energy) out of blood and stores as glycogen (stored energy) OR Converts glycogen into glucose if body needs Hormones regulate this

Pancreas Makes hormones, insulin and glucagon, which work together to control level of glucose in blood

The Hormones Insulin –Causes a decrease in blood glucose –If too much glucose, insulin triggers liver to store as glycogen Glucagon –Causes an increase in blood glucose –If not enough glucose, glucagon triggers liver to convert glycogen into glucose

The Cycle for Glucose Homeostasis 1.Blood glucose level is LOW 2.Pancreas releases glucagon 3.Glucagon directs liver to convert glycogen into glucose 4.Blood glucose level increases 5.Blood glucose level becomes too HIGH 6.Pancreas releases insulin 7.Insulin directs liver to store glucose as glycogen 8.Blood glucose level decreases 9.Cycle repeats

The Cycle

What happens if this cycle gets messed up? Diabetes mellitus –A condition of abnormally high blood glucose concentration

Type I Diabetes Juvenile-onset diabetes Severe childhood disorder in which insulin- producing cells of pancreas die Treated with daily injections of insulin

Type II Diabetes Adult-onset diabetes Usually diagnosed after age 40 More common and less severe Caused by insufficient amounts of insulin Hereditary, but its onset often correlates with obesity Often controlled with diet & exercise

Diabetes In people w/ diabetes, too much glucose inhibits water reabsorption by the kidneys, producing large amounts of urine Can result in kidney damage and dehydration

Lack of insulin Lack of insulin can cause: –Nausea & rapid breathing –Circulatory & nervous system failure –Urinary & Sexual Dysfunction –Diabetic coma –Death