homeostasis and diabetes l3. what is homeostasis? the maintenance of a constant internal...
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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.
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.
Hypoglycemia= LOW blood sugar
Glucagon: causes release of glucose from liverbreakdown of glycogen to glucose
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
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
Oral medications
Stimulate pancreas to secrete insulin Glyburide Many others
May need to add insulin in times of stress
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.
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
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