Control of Blood Sugar

1
Control of Blood Sugar

• Diabetes Mellitus

2
Maintaining Glucose Homeostasis

• Goal is to maintain blood sugar levels between 70
  and 110 mg/dL
• Two hormones play a role in maintaining glucose
  homeostasis
• Insulin
• Glucagon
• Both are pancreatic hormones
• See page 117

3
Lowering Blood Glucose Levels

• Blood glucose levels rise due to eating a
  carbohydrate containing meal
• In response, the pancreas releases insulin into
  the blood.
• Beta cells of the pancreas release insulin

4
Lowering Blood Glucose Levels

• Insulin
• Binds to insulin receptors on cells.
• Cells allow glucose to enter
• Stimulates liver and muscle cells to store
  glucose as glycogen
• Stimulates excess glucose to be converted into
  fat.
• As a result, blood glucose levels drop.

5
Raising Blood Glucose Levels

• Blood glucose levels drop as cells use glucose.
• In response, the pancreas releases glucagon into
  the blood.
• Alpha cells of the pancreas release glucagon

6
Raising Blood Glucose Levels

• Glucagon
• Stimulates liver cells to break down glycogen and
  release the glucose into the blood.
• As a result blood glucose levels rise.

7
Diabetes Mellitus

• Diabetes mellitus refers to a group of metabolic
  disorders in which the body is unable to regulate
  high blood glucose levels.

8
Diabetes Mellitus

• Two common forms
• Type 1 diabetes
• Other names
• Juvenile diabetes
• Insulin dependent diabetes mellitus (IDDM)
• Type 2 diabetes
• Other names
• Adult onset diabetes
• Noninsulin dependent diabetes mellitus (NIDDM)

9
Incidence of Diabetes

• Type 1 Diabetes
• 5-10 of diabetics
• Onset is generally before age 20
• Average age of onset 12
• Type 2 Diabetes
• 90-95 of diabetics
• Onset is generally between ages 10-19 or after
  age 40

10
Type 1 Diabetes

• Possible causes
• Autoimmune disorder
• Genetic component
• Immune system destroys beta cells of pancreas
• May also be caused by a viral infection that
  damages the pancreas

11
Type 1 Diabetes

• Pancreas is unable to make/secrete insulin.
• Glucose cannot enter cells ? hunger
• Blood glucose levels rise
• Glucose spills into the urine
• Water moves into blood
• Frequent need to urinate
• Thirsty

12
Type 1 Diabetes

• Cells use fats and proteins as an energy source,
  results in
• Weight loss ? hunger
• Ketones produced (due to overuse of fats for
  energy) ? potential for diabetic acidosis

13
Type 1 Diabetes

• Diabetic acidosis (ketosis)
• Ketones in breath
• Ketones in blood and urine
• ? can lead to diabetic coma

14
Type 1 Diabetes

• Treatment
• Insulin shots or pump
• Highly regulate intake of carbohydrates
• Consistent pattern of moderate carbohydrate
  intake to minimize fluctuations in blood glucose
• Closely monitor blood glucose levels

15
Type 2 Diabetes

• Associated with obesity
• As gain weight, cells make fewer insulin
  receptors
• Insulin doesnt bind as well to receptors made
• Genetic component
• More common as age

16
Type 2 Diabetes

• Fewer insulin receptors on cells
• Less insulin binds to cells
• Glucose enters cells SLOWLY
• Blood glucose levels remain elevated
• Glucose spills into the urine
• Water moves into blood
• Frequent need to urinate
• Thirsty

17
Type 2 Diabetes

• Glucose enters cells slowly
• No need to use proteins or fats for energy
• Hungry
• Eat more ? gain weight
• Exacerbates the problem

18
Type 2 Diabetes

• Pancreas continues to make insulin
• Often in large amounts to compensate for the
  insulin resistance of cells
• May get to point where pancreas cannot keep up
  with the bodys needs and insulin is required.

19
Type 2 Diabetes

• Recommendations
• Lose weight
• Even moderate weight loss can help
• Exercise
• Increases number of insulin receptors
• Improves binding of insulin to the receptors
• Helps with weight loss

20
Chronic Complications of Diabetes

• Regular high blood glucose levels result in
• Cells making sugar alcohols
• Glucose binds to proteins on cells, damages cells
• Results in
• Damage to blood vessels and nerves
• Slowed healing
• Unaware of wounds? amputation
• Kidney damage ? kidney failure
• Damage to cells of eyes ? blindness

21
Chronic Complications of Diabetes

• Other
• Increased risk of
• Coronary heart disease
• Elevated blood lipid levels
• Hypertension