Homeostasis and Diabetes L3

What is Homeostasis?

The maintenance of a constant

internal environment,

despite external changes is called

Homeostasis

What is Homeostasis?

Body cells work best if they have the correct Temperature Water levels

Glucose concentration

Your body has mechanisms to keep the cells in a constant environment.

Where is the pancreas?

Pancreatic endocrine functions

cells: make insulin (stores glucose) = ¾ of the cells; secrete Insulin

cells: make glucagon to (mobilize glucose)

¼ of the cells; secrete Glucagon

The pancreas also secretes enzymes needed in digestion

Insulin and the 3-”G’s”

Insulin: (anabolic). Initiates buildup of glucose to store as glycogen.

1. Glucagon: (catabolic). Breaks down stored glycogen into glucose.

2. Glycogen is stored form of glucose.

3. Glucose: usable form of sugar present in blood.

Controlling Glucose levels

Your cells (muscles, brain, etc) need an exact level of glucose in the blood. (normal serum level 65 – 105 mg)

Excess glucose gets turned into glycogen in the liver and muscles

Blood glucose levels are regulated by 2 hormones (chemical messengers) from the pancreas called:

InsulinGlucagon

Normal Maintenance of Blood Glucose Levels

Eat a meal: Pancreas detects increased glucose

levels in blood and secretes INSULIN This results in uptake of GLUCOSE by:

Cells that need it for energy (including brain)

Liver and muscle cells to be stored as glycogen

Pancreas stops release of Insulin Glucose levels return to normal (80-

120)

Time

Glucose Concentration

Meal eaten

Insulin is produced and glucose levels fall to normal again.

Glucose levels rise after a meal.

Normal

Normal maintenance, cont.

Insulin secretion regulated by Negative Feedback of blood glucose levelsHigh blood glucose stimulates insulin secretion

Low blood glucose inhibits insulin secretion

If there is too much glucose in the blood, Insulin tells the liver to convert some of it to glycogen

Glycogen

Insulin

Glucose in the blood

Normal Maintenance of Blood Glucose Levels, cont.

Blood glucose drops due to NOT eating

Pancreas detects and releases glucagon stimulates the release of glycogen

(broken down to glucose) Glucose is released into the blood

and levels return to normal.

If there is not enough glucose in the blood, Glucagon tells the liver to convert glycogen into glucose.

Glycogen

Glucagon

Glucose in the blood

Normal Maintenance, cont.

Release of Glucagon also regulated by Negative Feedback mechanism sensitive to glucose levels in blood.Low blood sugar stimulates glucagon secretion

High blood sugar inhibits glucagon secretion

Diabetes

Some people do not produce enough insulin.

When they eat food, the glucose levels in their blood cannot be reduced.

This condition is known as DIABETES.

Diabetics sometimes have to inject insulin into their blood. They have to be careful of their diet.

Time

Glucose Concentration

Meal eaten

Insulin is not produced so glucose levels stay high

Glucose levels rise after a meal.

Diabetic

The glucose in the blood increases,

Glycogen

Insulin

Glucose in the blood

but there is no insulin to tell the liver to convert it into glycogen.Glucose concentration rises to dangerous levels.

Hyperglycemia= high blood glucose levels

Drowsy Flushed Thirsty

Hypoglycemia= LOW blood sugar

Glucagon: causes release of glucose from liverbreakdown of glycogen to glucose

Hypoglycemia

Weak, sweaty Confused/

irritable/ disoriented

Diabetes MellitusComplications

Major health problem US/worldwide Complications [Poor blood

vessels/circulation (PVD] Blindness (L3: retinal proliferation, macular

degeneration) Renal failure Amputations Cardiovascular disease (heart attack)

Cerebrovascular disease (strokes) [OB/neonatal complications] Diabetic neuropathy

Erectile dysfunction

Diabetes Mellitus

The good news:Blood glucose control reduces complications of Diabetes!

What is going on?

Absence (or ineffectiveness of ) insulin

Cellular resistanceCells can’t use glucose for

energyStarvation mode

Compensatory breakdown of body fat/protein (ketone breath: smells like alcohol)

Side Effects

HYPERGLYCEMIA: fluid/electrolyte imbalance. Sodium, chloride, potassium excreted

(frequent urination) Dehydration (thirsty all the time) cells are starving, so person feels

hungry despite eating huge amounts of food. Starvation state remains until insulin is available. (eats too much)

Type I Diabetes

MUST HAVE INSULIN WHICH IS INJECTED!!! Can also have oral medications too to help.

Cause: autoimmune-happens at birth or by teen years. (AKA:juvenile diabetes) Beta cell destruction in genetically

susceptible person

Some viral infections: can destroy beta cells

Type II Diabetes

Can have insulin but usually given oral meds.

Cause/Who gets it- usually adult onset but a problem on the rise in children Reduction in ability of most cells to

respond to insulin Poor control of liver glucose output Decreased beta-cell function (eventual

failure)

Risk Factors for Type II

Major risk factors Family history Obesity Origin (Afro-American, Hispanic, Native

American, Asian-American) Age (older than 45) History of gestational diabetes High cholesterol Hypertension

Preventions

Prevention of effects: combination approach Increased exercise

Decreases need for insulin Reduce calorie intake

Improves insulin sensitivity Weight reduction

Improves insulin action

Triad of Treatment

Diet Medication

Oral hypoglycemics

Insulins Exercise

Oral medications

Stimulate pancreas to secrete insulin Glyburide Many others

May need to add insulin in times of stress

Insulin

Moves glucose into cells (thus acts like growth hormone in a way)

Needs to be injected

Insulin preparations

Rapid acting Short acting

(regular) Intermediate

acting (NPH) Long acting

Some things to know…L3

Dawn Phenomenon and Somogi’s effect Dawn phenomenon

Blood sugar rises in early morning

Somogi’s (rebound) effect Blood sugar rise in morning as reaction to

hypoglycemic time during the night

Some things to know…L2/L3

Diabetic foot care Dry, cracked skin + poor circulation

could = loss of a limb

For the most part nurses don’t trim nails of diabetic clients. Refer to Podiatrist.

Typical diabetic foot ulcer

Quick Quiz:

1. Give name of the very important anabolic hormone that builds up glucose and stores it as glycogen.

2. What is the usable form of sugar in the blood called?

3. What are the cells associated with insulin production called?

4. What is the main problem (physiologically) that exists in people that are diabetic?

Quick Quiz, cont.

5. In a normal person without diabetes, __________ ____________will result thus allowing high blood _________ to stimulate

Insulin secretion.

6. Low blood sugar will stimulate what to be released?

7. Describe how someone would look/act if they were hyperglycemic

Quick Quiz, cont.

8. Describe someone who is hypoglycemic

9. List 3 treatments/preventions for diabetes and label if they are for Type 1, 2 or both

10. What is the good news for diabetes?