Homeostasis - Hormone That Affect Blood Sugar

Question 1

What are the islets of Langerhans?

Answer 1

Clusters of endocrine cells inside the pancreas that contain alpha, beta, and delta cells which produce hormones that regulate blood sugar

Question 2

What hormone is produced by alpha cells?

Answer 2

Glucagon: used to raise blood sugar levels

Question 3

What hormone is produced by beta cells?

Answer 3

Insulin: used to lower blood sugar levels

Question 4

What hormone is produced by delta cells?

Answer 4

Somatostatin: used to inhibit the release of insulin and glucagon by the islets of Langerhans

Question 5

How does insulin regulate blood sugar levels?

Answer 5

• Lowers blood sugar levels
• Increases permeability of muscle + liver cells to glucose, drawing glucose out of blood and into cells
• In liver glucose is converted to glycogen (storage form)
• Example: after meal, glucose levels rise so insulin is released to lower them

Question 6

How does glucagon regulate blood sugar levels?

Answer 6

• Increases blood sugar levels
• Glucagon promotes conversion of glycogen to glucose, which is released into the blood, raising blood sugar
• Example: during sleep, glucose levels decrease so glucagon is released into blood to raise them

Question 7

Type I diabetes

Answer 7

• Juvenile-onset
• Early degradation of beta cells
• Pancreas unable to produce insulin
• Diagnosed early
• People must take insulin to survive
• Approx. 10% of diabetics

Question 8

Type II diabetes

Answer 8

• Adult-onset
• Either body decreases insulin production or uses it ineffectively
• Diagnosed in adulthood
• Can be controlled w/ proper diet, exercise, oral medication, + insulin injections in later stages
• Approx. 90% of diabetics

Question 9

Gestational diabetes

Answer 9

• Occurs when mother’s pancreas is unable to produce sufficient insulin during pregnancy
• Temporary condition (2-4% of pregnancies)
• Increases risk of type II in mom and type I in unborn child
• Can lead to abnormally large fetal size (macrosomia) due to increased blood sugar levels
• Can be controlled w/ proper diet, exercise, + insulin injections

Question 10

Adrenal medulla

Answer 10

• Inner gland of adrenal gland
• Produces catecholamines that respond to short-term stress: epinephrine (adrenalin) + norepinephrine
• Stimulated by nervous system

Question 11

Short-term stress response

Answer 11

• Catecholamines
• Epinephrine (adrenalin) + norepinephrine
• When they exist in blood, blood sugar levels rise as glycogen is quickly converted to glucose (quick energy source)
• Heart + breathing rate and cell metabolism decreases
• Iris of eye dilates

Question 12

Adrenal cortex

Answer 12

• Outer gland of adrenal gland
• Produces 3 different types of hormones that deal with long-term stress: glucocorticoids, mineralocorticoids, androgens (sex hormones)
• Stimulated by hormones

Question 12

Long-term stress response

Answer 12

• Hypothalamus sends releasing hormone to anterior love of pituitary gland, which simulates release of adrenocorticotropic hormone (ACTH)
• Blood carries ACTH to adrenal cortex
• ACTH influences adrenal cortex to release mineralocorticoids + glucocorticoids, which are carried to target cells in liver + muscles

Question 13

Glucocorticoids

Answer 13

• Cortisol increases number of amino acids in blood to help body recover from stress
• Amino acids converted to glucose by liver, raising blood sugar level + increasing energy reserves in blood
• Fats converted to fatty acids (another energy source)
• Decreases glucose uptake by muscles (not brain)

Question 14

Mineralocorticoids

Answer 14

• Example: aldosterone
• Increases sodium retention + water reabsorption in kidneys
• Helps maintain body fluid level