nutrients & homeostasis. metabolism & body heat metabolism –all of the chemical reactions...
Post on 30-Dec-2015
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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 1700-2500 calories per day
• Exercise use more caloriesgive off more heat
• Nervous use more caloriesgive 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 LOW2. Pancreas releases glucagon3. Glucagon directs liver to convert glycogen into
glucose4. Blood glucose level increases5. Blood glucose level becomes too HIGH6. Pancreas releases insulin7. Insulin directs liver to store glucose as glycogen8. Blood glucose level decreases9. Cycle repeats
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
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