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

Making food usable

Intestine absorbs it

Insulin is released

Liver converts it to glycogen

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.

CO2 +H2O releasedNo O2 required

O2 requiredLot of ATP released

No O2 required

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

Electron Transport Chain

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

Skin Ulcer in a Diabetic Food

Poor Circulation

Loss of feeling

Neuropathy

Ulceration and Infection

Planned Amputation

Before & After Type I or Type II

Either can lead to

Poor circulation &

Neuropathy

Ingrown Toenails

Foot Care Skill:

Cut with a round Cut