Endocrine System Chapter 17 Flashcards

Questions and Answers

What is the pancreatic endocrine tissue?

The pancreatic islets.

What are the main islet cell types?

Alpha, beta, and delta cells.

What are the effects of glucagon when secreted between meals?

Stimulates gluconeogenesis and glycogenolysis in the liver, raising blood glucose levels; stimulates fat breakdown in adipose tissue.

What is the effect of insulin secreted during and after meals?

Stimulates cells to absorb nutrients, lowers blood glucose levels, and promotes storage of excess nutrients. Signup and view all the answers

What effects does somatostatin have when released along with insulin?

Limits secretion of stomach acid, slows stomach emptying, and reduces blood glucose spikes. Signup and view all the answers

What are the main endocrine hormones secreted by the testes?

Testosterone and inhibin. Signup and view all the answers

How does testosterone work?

LH acts on interstitial cells to secrete testosterone, which supports sperm production and secondary sex characteristics. Signup and view all the answers

How does inhibin work?

Limits FSH secretion to regulate sperm production. Signup and view all the answers

What hormones are secreted by the skin?

Cholecalciferol, which leads to vitamin D3 synthesis. Signup and view all the answers

What hormones are secreted by the liver?

A form of angiotensin. Signup and view all the answers

What hormones are secreted by the kidneys?

Erythropoietin. Signup and view all the answers

What hormones are secreted by the heart?

Atrial natriuretic proteins (ANP). Signup and view all the answers

What hormones are secreted by the stomach and intestines?

Cholecystokinin, gastrin, ghrelin, and leptin. Signup and view all the answers

What are the three hormone classes?

Steroids, monoamines, peptides. Signup and view all the answers

What are steroids derived from?

Cholesterol. Signup and view all the answers

What are monoamines?

Small molecules made from amino acids. Signup and view all the answers

What are peptides?

Long chains or rings of amino acids. Signup and view all the answers

How are hormones transported to their target cells?

In the blood; monoamines and peptides are hydrophilic, whereas steroids and thyroid hormones are hydrophobic and require transport proteins. Signup and view all the answers

Study Notes

Pancreatic Endocrine Tissue

Pancreatic islets consist of endocrine tissue responsible for hormone secretion.
Main islet cell types: alpha, beta, and delta cells, each producing distinct hormones.

Alpha Cells

Secrete glucagon, which raises blood glucose levels during fasting.
Stimulates gluconeogenesis (glucose synthesis) and glycogenolysis (breakdown of glycogen) in the liver.
Promotes fat metabolism in adipose tissue; increases free fatty acid release.
Glucagon secretion is triggered by low blood glucose or rising amino acid levels post high-protein meals.

Beta Cells

Produce insulin, which lowers blood glucose levels after meals.
Insulin facilitates nutrient absorption, promoting glycogen, fat, and protein synthesis.
Acts as an antagonist to glucagon, inhibiting the use of stored fuels.
Insulin insufficiency is linked to diabetes mellitus.

Delta Cells

Secrete somatostatin alongside insulin during and after meals.
Somatostatin limits stomach acid secretion, slowing gastric emptying.
Reduces blood glucose spikes; works with amylin to prolong nutrient absorption.

Testes and Their Hormones

Testes secrete testosterone and inhibin.
Testosterone is regulated by luteinizing hormone (LH) from the pituitary, supporting sperm production and secondary sex characteristics.
Inhibin, released from sustentacular cells, regulates follicle-stimulating hormone (FSH) to control sperm production.

Skin Hormone Secretion

Keratinocytes convert cholesterol-like steroids into cholecalciferol, aiding vitamin D3 synthesis through UV exposure.

Liver Hormones

The liver secretes various hormones, including a form of angiotensin, which is a vasoconstrictor that elevates blood pressure.

Kidney Hormones

Kidneys secrete erythropoietin, stimulating red blood cell production in the bone marrow.

Heart Hormone Secretion

The heart releases atrial natriuretic peptide (ANP), which lowers blood volume and pressure by promoting sodium and water excretion via the kidneys.

Stomach and Intestine Hormones

Produce hormones related to digestion and appetite:
- Cholecystokinin: stimulates bile release from the gallbladder.
- Gastrin: increases stomach acid secretion.
- Ghrelin and leptin: regulate appetite, secreted by the stomach and adipose tissue.

Hormone Classes

Three primary classes of hormones: steroids, monoamines, peptides.

Steroid Hormones

Derived from cholesterol, synthesized in gonads and adrenal cortex.

Monoamine Hormones

Small molecules derived from amino acids characterized by amino groups.
Melatonin is synthesized from tryptophan; other monoamines from tyrosine.

Peptide Hormones

Composed of long chains or rings of amino acids, synthesized through transcription and translation processes.

Hormone Transport

Hormones circulate in blood; monoamines and peptides are hydrophilic and exist as unbound hormones.
Steroids and thyroid hormones are hydrophobic, requiring transport proteins and existing as bound hormones.

Stimuli Influencing Hormone Secretion

Hormone secretion is influenced by various stimuli, including changes in blood chemistry, neural input, and other hormonal signals.

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Description

Test your knowledge of the endocrine system with these flashcards from Chapter 17. Learn about the pancreatic islets, specific islet cell types, and the functions of hormones like glucagon. Perfect for students looking to reinforce their understanding of this critical body system.