Post on 30-Dec-2015
transcript
Nutrition and Metabolism
Negative Feedback System
Pancreas: Hormones in Balance
Insulin & GlucagonHormones that affect the level of sugar in the blood
A. Meal is eaten …… food is converted to glucose
B. Intestines absorb the glucoseC. Glucose enters the bloodstream;
Blood glucose levels rise D. Pancreas produces insulin
E. Liver & other tissue cells take in glucose
F. Blood sugar level drops and pancreas stops secreting insulin
How Food is digested
When Blood Sugar Levels Decrease: Hungry or
Starving And the body needs glucose
Glucagon is released by the pancreas
& Stimulates the conversion of glycogen in the liver to glucose
raises the level of glucose (sugar) in the blood
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Insulin is the only hormone that Decreases Blood Sugar Levels
Help glucose across the plasma membrane
Once inside the cell, glucose is oxidized for energy OR
Converted to glycogen (in the liver) or
fat for storage
Blood sugar (glucose) levels will FALL and Insulin release ends
The pancreas should produce enough insulin for the body
Insulin stimulates cells to use glucose
protein, fats, and carbohydrates will be broken down into usable glucose or converted to stored glycogen in the liver
Or synthesize lipids
Negative-FeedbackTotally responding to blood glucose
Either insulin or glucagon are working
in this cycle of hormones
Another one involved: Somatostatin may
regulate the secretion of glucagons and insulin
Glucagon - Hormone of metabolism
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When the body needs glucose glucagon converts amino acids & breaks down lipids in the liver - to make glucose available
Stored glycogen in the liver is convertedinto usable glucose in the bloodstream
Main Target is the Liver
Pancreas releases either glucagon or insulin into the blood stream
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Has high bloodSugar -Releases Insulin
Needs glucose
Has not eatenrecently
Releases glucagon
OR
Cellular Metabolism & Respiration Series of chemical reactions that happen in
every cell of living organisms.
glucose + oxygen carbon dioxide + water
C6H12O6 + O2 CO2 + H20
• The reactions release energy.
Oxidation reactions because they remove electrons & add them to the oxygen in water.
Cellular Respiration Three Processes Glycolysis
Takes place in the cytoplasm Releases small amounts of ATP Does not require oxygen.
Krebs Cycle Takes place in the mitochondria Uses products from glycolysis Produces a small amount of ATP Produces CO2 and H2O
Electron Transport Chain. Takes place in the mitochondria Releases the majority of ATP
Specific pancreatic cells make
Insulin
Glucagon
75% of Beta cells make insulin 25% Alpha cells make glucagon
Glucose Levels are tightly regulated
Normal levels are 70 to 125 mg /dL (random sampling - not “fasting”)
Hypoglycemia > Low blood sugar
Hyperglycemia > High blood sugar
Insulin controls blood sugar Insulin binds to receptors on the cell membranes and activates them.
This activates metabolism inside the cell which allows the uptake, utilization and storage of glucose.
Lack of insulin results in an increase in blood glucose concentration
Insulin Effects
Insulin stimulates the liver to convert glucose to glycogen for short term storage.
Insulin promotes to conversion of glycogen to fats for long term storage.
Insulin inhibits the breakdown of fats.
Insulin stimulates the uptake of amino acids.
Diabetes Mellitus- Type 1Insulin insufficiencyPancreas doesn’t produce enoughRequires insulin replacement therapy.
Requires monitoring blood sugar, and matching your insulin supply with carbohydrate intake and exercise.
Insulin must be injected.
Diabetes mellitus Type 2 Cells become resistant to insulin.
Adult onset Insulin is ineffective- must be controlled by diet and exercise.
Consequences of Diabetes Poor circulation because the arteries become thicker and less elastic. Sores on the limbs that heal poorly
Foot damage Higher cholesterol and triglyceride levels
Eye damage Dementia Tooth and gum problems Heart Disease