chapter033

Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 33

Diabetes Mellitus and the Metabolic Syndrome

Chapter 33

Diabetes Mellitus and the Metabolic Syndrome


Anabolism and CatabolismAnabolism and Catabolism

AnabolismInsulin, anabolic steroids

Catabolismglucagon,

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 ControlsInsulin and Glucagon Are the Main Controls

AnabolismInsulin , anabolic steroids

CatabolismGlucagon , epinephrine,

cortisol


glucose

amino acids

free fatty acids


glycogen

proteins

triglycerides


ketones


Question Question

Tell whether the following statement is true or false:

Anabolic reactions release energy.


Answer 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).


ScenarioScenario

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 PancreasThe PancreasPancreas

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

Pancreatic polypeptide

Glucagon Insulinand amylin Somatostatin


Functions of Pancreatic HormonesFunctions 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


QuestionQuestion

Which pancreatic hormone decreases blood glucose levels?

a. Glucagon

b. Insulin

c. Amylin

d. Somatostatin


Answer 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.


DiscussionDiscussion

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?



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?



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?


Anabolism and CatabolismAnabolism and Catabolism

AnabolismInsulin, anabolic steroids

Catabolismglucagon,

epinephrine, cortisol


glucose

amino acids

free fatty acids


glycogen

proteins

triglycerides


ketones


Types of Diabetes MellitusTypes 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 DiabetesPathogenesis of Type 2 Diabetes


Question Question

Tell whether the following statement is true or false:

Type 2 DM is more common than Type 1 DM.


Answer 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 SyndromeMetabolic Syndrome

• Abdominal obesity

• Increased blood triglyceride levels

• Decreased HDL levels

• Increased blood pressure

• Increased fasting plasma glucose


Acute Complications of DiabetesAcute Complications of Diabetes

• Diabetic ketoacidosis

• Hyperglycemic hyperosmolar nonketotic coma

• Hypoglycemia

• Somogyi effect

• Dawn phenomenon


Discussion

• How would hyperglycemia with ketoacidosis cause:

– Heavy breathing?

– Polyuria?

– Dehydration?

• Which of these would you not see in hyperglycemia without ketoacidosis?

Acute Complications of Diabetes (cont.)Acute Complications of Diabetes (cont.)


ScenarioScenario

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 MellitusChronic 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 MellitusOsmolarity 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 NeuropathyDiabetic 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 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 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.

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blood glucose levels

blood levels

glucose absorption

insulin secretioncopyright

stimulatesmovement of

scenariotwo women

thesetwo women