Endocrine Pancreas

Question 1

What is the Endocrine Pancreas composed of?

Answer 1

Clusters of cells termed islets of Langerhans

Question 2

What makes up a single islet?

Answer 2

It contains multiple cell types, with each cell producing one type of hormone.

Question 3

What lies in the center of islets? What do they secrete?

Answer 3

Beta cells

-Secrete insulin

Question 4

What is insulin?

Answer 4

Major anabolic hormone

Question 5

What function does insulin do?

Answer 5

Increases glucose uptake by tissues and leads to increased glycogen synthesis, protein synthesis and lipogenesis.

Question 6

What does insulin upregulate?

Answer 6

Insulin-dependent glucose transporter protein (GLUT4) on skeletal muscle and adipose tissue (glucose uptake by GLUT4 decreases serum glucose)

Question 7

What secretes glucagon?

Answer 7

Alpha cells

Question 8

How does glucagon function?

Answer 8

It opposes insulin in order to increase blood glucose levels (e.g. in states of fasting) via glycogenolysis and lipolysis

Question 9

What is Type I Diabetes Mellitus?

Answer 9

Insulin deficiency leading to a metabolic disorder characterized by hyperglycemia.

Question 10

What is the cause of Type I Diabetes Mellitus?

Answer 10

Autoimmune destruction of beta cells by T lymphocytes

Type IV hypersensitivity

Question 11

What are three microbiological characteristics of Type I Diabetes Mellitus?

Answer 11

1. Characterized by inflammation of islets
2. Associated with HLA-DR3 and HLA-DR4
3. Autoantibodies against insulin are often present (sign of damage) and may be seen years before clinical disease develops

Question 12

When does Type I Diabetes manifest?

Answer 12

In childhood

Question 13

What is a clinical feature of Type I Diabetes?

Answer 13

Insulin deficiency

Question 14

What is seen in the serum of Type I Diabetics?

Answer 14

High serum glucose

Question 15

What causes high serum glucose in Type I Diabetics?

Answer 15

Lack of insulin leads to decreased glucose uptake by fat and skeletal muscle

Question 16

What are three symptoms of Type I Diabetes related to weight?

Answer 16

1. Weight loss
2. Low muscle mass
3. Polyphagia (eat a lot)

Question 17

What does unopposed glucagon lead to in Type I Diabetics?

Answer 17

Gluconeogenesis (break down of muscle), Glycogenolysis (break down of glycogen) and Lipolysis (break down of fat) —> These further exacerbate hyperglycemia

Question 18

What are three Type I diabetes symptoms related to urine output?

Answer 18

Polyuria (large urine volume), polydipsia (excessive thirst) and glycosuria (secretion of glucose in the urine)

Question 19

What causes glycosuria in Type I diabetes?

Answer 19

-Hyperglycemia exceeds renal ability to resorb glucose

Question 20

What does excess filtered glucose lead to in Type I diabetes?

Answer 20

Osmotic diuresis

Question 21

What is the treatment for Type I diabetes?

Answer 21

Lifelong insulin

Question 22

What condition are Type I diabetics at risk for?

Answer 22

Diabetic ketoacidosis

Question 23

What is diabetic ketoacidosis characterized by?

Answer 23

Excessive serum ketones

Question 24

When does Diabetic Ketoacidosis often arise?

Answer 24

With stress (e.g. infection)

Question 25

How does stress (e.g. infection) contribute to DKA?

Answer 25

Epinephrine stimulates glucagon secretion increasing lipolysis (along with gluconeogenesis and glycogenolysis)

Question 26

What does increased lipolysis cause?

Answer 26

Leads to increased free fatty acids (FFAs)

Question 27

What does the liver do with the FFAs in Diabetic Ketoacidosis?

Answer 27

It converts FFAs into ketone bodies | e.g. beta-hydroxybutyric acid and acetoacetic acid

Question 28

What are two common ketone bodies?

Answer 28

Beta-hydroxybutyric acid | Acetoacetic acid

Question 29

What altered labs does DKA present with?

Answer 29

Hyperglycemia (>300 mg/dL), anion gap metabolic acidosis, and hyperkalemia

Question 30

Why is the hyperkalemia in DKA deceiving?

Answer 30

Hyperkalemia in serum is lost in urine over time. | --> So over time K+ becomes low in the body

Question 31

What symptoms does DKA present with?

Answer 31

- Kussmaul respirations - Dehydration - Nausea - Vomiting - Mental status changes - Fruity smelling breath (due to acetone)

Question 32

What is the treatment for DKA?

Answer 32

- Fluids (corrects dehydration from polyuria) - Insulin - Replacement of electrolytes (e.g. potassium)