Endocrine System Flashcards
What commonalities exist in the overall functions of the nervous system (NS) and the endocrine system?
Both serve for internal communication and both use chemical transmitters.
Can a single chemical function as both a neurotransmitter and a hormone? If so, give examples.
Yes, norepinephrine, dopamine, and ADH
What structures constitute the endocrine system?
It is made up of all the glands, tissues, and cells that secrete hormones.
What is the definition of “gland”?
A bodily structure responsible for producing various substances, such as hormones, digestive fluids, sweat, tears, saliva, or milk.
Is the pancreas classified as an exocrine or endocrine gland? Why?
Both. Acinar cells release digestive enzymes into ducts and the pancreatic islets release hormones into the blood.
What are the islets of Langerhans, and where are they located?
Endocrine cell clusters are called pancreatic islets. They are scattered throughout the pancreas.
Which specific pancreatic cells are responsible for the production of the hormones insulin, amylin, and glucagon?
Beta cells produce insulin and alpha cells produce glucagon.
In the regulation of glucose homeostasis, which pancreatic hormones play a pivotal role?
Insulin, amylin, and glucagon?
Concerning the control of glucose levels, are the functions of insulin and glucagon similar or distinct?
Insulin and glucagon have antagonistic effects. Insulin has glucose-lowering effects while glucagon tends to raise circulating glucose levels.
What initiates the release of insulin from the pancreas?
Increase in blood glucose levels, such as after a meal.
Define glycogenesis and clarify whether insulin or glucagon promotes or inhibits these metabolic reactions.
Simulated by insulin, glycogenesis is the process by which glucose is converted into glycogen for storage in liver and muscle cells.
Define gluconeogenesis and clarify whether insulin or glucagon promotes or inhibits these metabolic reactions.
Gluconeogenesis is the synthesis of glucose from non-carbohydrate sources, such as amino acids and glycerol, primarily in the liver and kidneys. It is inhibited by insulin and promoted by glucagon.
Define glycogenolysis and clarify whether insulin or glucagon promotes or inhibits these metabolic reactions.
Glycogenolysis is the breakdown of glycogen into glucose, releasing it into the bloodstream to be used for energy. It is promoted by glucagon.
What are the overall effects of insulin on adipose tissue and muscle?
Insulin increases glucose uptake in adipose tissue and muscle.
Which metabolic reactions does insulin influence in the liver?
Stimulate glycogenesis in the liver while it inhibits gluconeogenesis.
When is amylin secreted, and what functions does it serve?
Amylin is simultaneously secreted with insulin, decreasing spikes in blood glucose by suppressing appetite, slowing gastric emptying, and inhibiting glucagon release.
What triggers the release of glucagon from the liver, and what are its primary functions?
Decrease in blood glucose levels, such as after a meal. Glucagon raises blood glucose levels by promoting the breakdown of glycogen into glucose (glycogenesis) and the synthesis of glucose from non-carbohydrate sources.
What is the role of GLUT 4?
GLUT-4 or glucose transporter type 4 is responsible for transporting glucose from the bloodstream into cells, particularly muscle and adipose (fat) cells.
What is the definition of diabetes mellitus (DM)?
A metabolic disease, involving inappropriately elevated blood glucose levels.
Describe type 1 diabetes mellitus.
Attack on the autoimmune system causes pancreatic B (beta) cell destruction subsequently causing a deficiency of insulin. Diagnosis occurs before the age of 30, and patients require insulin injections.
Describe type 2 diabetes mellitus.
Peripheral resistance to insulin action (decreasing sensitivity) and inadequate compensatory response of insulin secretion by the pancreas (progressive loss of β-cells function). Diganosis occurs after the age of 40.
