Chapter033

Chapter 33
Diabetes Mellitus and the
Metabolic Syndrome
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Anabolism and Catabolism
Anabolism
Insulin,
anabolic
steroids
Catabolism
glucagon,
epinephrine,
cortisol
available foodstuffs
(in blood)
glucose
amino acids
free fatty acids
stored foodstuffs
(in cells)
glycogen
proteins
triglycerides
liver can convert amino acids
and free fatty acids into
ketones

Insulin and Glucagon Are the Main
Controls
Anabolism
Insulin ,
anabolic
steroids
Catabolism
Glucagon ,
epinephrine,
cortisol
available foodstuffs
(in blood)
glucose
amino acids
free fatty acids
stored foodstuffs
(in cells)
glycogen
proteins
triglycerides
liver can convert amino acids
and free fatty acids into
ketones

Question
Tell whether the following statement is true or false:
Anabolic reactions release energy.

Answer
False
Anabolic reactions use energy to build/produce/synthesize
(like building proteins from amino acids). Catabolic
reactions break down substances, releasing energy in the
process (like digestion).

Scenario
Two women have benign pancreatic tumors...
• In one, the tumor is an insulinoma that secretes insulin
• In the other, the tumor is a glucagonoma that secretes
glucagon
Question
• What differences do you expect to see between these
two women? Why?
• Both of the women have arthritis, but only one is being
treated with corticosteroids. Which one? Why is the
other not receiving corticosteroids?

The Pancreas Pancreas
Exocrine
pancreas
releases digestive
juices through a
duct
to the
duodenum
Endocrine
pancreas
releases hormones
into the blood

Endocrine
pancreas:
Islets of
Langerhans
Alpha
cells Beta cells Delta cells PP cells
Insulin
and amylin Somatostatin
Pancreatic
Glucagon polypeptide

Functions of Pancreatic Hormones
• Glucagon: causes cells to release stored food
into the blood
• Insulin: allows cells to take up glucose from the
blood
• Amylin: slows glucose absorption in small
intestine; suppresses glucagon secretion
• Somatostatin: decreases GI activity; suppresses
glucagon and insulin secretion

Question
Which pancreatic hormone decreases blood glucose levels?
a. Glucagon
b. Insulin
c. Amylin
d. Somatostatin

Answer
b. Insulin
Insulin allows cells to take glucose from the blood and use
it for energy/to make ATP. Because it stimulates
movement of glucose out of the blood and into the cells,
blood levels decrease when insulin is released.

Discussion
Think back on your day so far.
• When do you think you had your highest insulin
levels?
• When do you think you had your lowest insulin
levels?
• When did you have your highest glucagon
levels?

Discussion
Review the figure on Insulin's Actions
• If someone lacks insulin, what happens to his:
– Blood glucose levels?
– Blood amino acid levels?
– Blood pH?
– Intracellular fat levels?
– Intracellular protein levels?
– Cell growth?

Discussion
Review the following diagrams on
anabolism/catabolism and insulin's mechanism of
action
Question
• Identify five things that could go wrong to cause
increased blood glucose
• Which of the cases you identified would be least
likely to respond to insulin?

Types of Diabetes Mellitus
• Type 1: pancreatic beta cell destruction predominantly
by an autoimmune process
• Type 2: a combination of beta cell dysfunction and
insulin resistance
• Other
– Genetic defects in insulin production
– Genetic defects in insulin action
– Diabetes secondary to other diseases
– Drug interactions
• Gestational diabetes mellitus

Pathogenesis of Type 2 Diabetes

Question
Tell whether the following statement is true or false:
Type 2 DM is more common than Type 1 DM.

Answer
True
Type 1 DM is autoimmune (juvenile diabetes is Type 1),
and affects only 5% to 10% of the diabetic population.
Type 2 DM is associated with risk factors like obesity,
poor diet, and sedentary lifestyle; 90% to 95% of
diabetics suffer from this type.

Metabolic Syndrome
• Abdominal obesity
• Increased blood triglyceride levels
• Decreased HDL levels
• Increased blood pressure
• Increased fasting plasma glucose

Acute Complications of Diabetes
• Diabetic ketoacidosis
• Hyperglycemic hyperosmolar nonketotic coma
• Hypoglycemia
• Somogyi effect
• Dawn phenomenon

Acute Complications of Diabetes (cont.)
Discussion
• How would hyperglycemia with ketoacidosis cause:
– Heavy breathing?
– Polyuria?
– Dehydration?
• Which of these would you not see in hyperglycemia
without ketoacidosis?

Scenario
You find a man collapsed on the sidewalk…
• He is wearing a diabetic alert bracelet and has an
insulin syringe in his briefcase
Question
• Does he need insulin?
• Why or why not?
• What signs might help you tell whether he has a
hyperglycemic or hypoglycemic problem?

Chronic Complications of Diabetes Mellitus
• Increased glucose levels allow glucose to bind to
proteins in:
– Hemoglobin  Hb A1C has higher O2 affinity
– Basement membranes of blood vessels
º Nephropathy
º Retinopathy
º May cause increased risk of atherosclerosis
– Lens  cataracts

Osmolarity in Diabetes Mellitus
• When blood glucose is high, increased blood osmolarity
can cause cells to shrink
• Nerve cells produce intracellular osmoles to keep their
osmolarity balanced with the blood
• When the client brings blood glucose back to normal, the
nerve cells are hyperosmolar to the blood and gain
water, swelling
• Nerve damage may be caused by swelling,
demyelination, and lack of O2 secondary to vascular
disease

Diabetic Neuropathy
• Somatic neuropathy
– Diminished perception of vibration, pain, and
temperature
– Hypersensitivity to light touch; occasionally
severe “burning” pain
• Autonomic neuropathy
– Defects in vasomotor and cardiac responses
– Impaired motility of the gastrointestinal tract
– Inability to empty the bladder
– Sexual dysfunction

Question
Which of the following is not a complication of diabetes
mellitus?
a. Nephropathy
b. Retinopathy
c. Neuropathy
d. All of the above are complications of DM.

Answer
d. All of the above are complications of DM.
Nephropathy and retinopathy are caused by increased
blood glucose levels that cause binding of excess
glucose to the basement membranes of the blood
vessels of the kidneys and eyes. Neuropathy is due to
swelling and demyelination of nervous tissue.

Chapter033

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