Hormone Classification and Signaling

Questions and Answers

Under which chemical class would a hormone containing four amino acids linked together be classified?

Steroid hormone

Lipid-derived hormone

Peptide hormone (correct)

Amino acid-derived hormone

Which class of hormones can diffuse through plasma membranes?

Amino acid-derived hormones

Insulin

Peptide hormones

Lipid-derived hormones (correct)

What is an amino acid-derived hormone?

A hormone derived from amino acids

What is a lipid-derived hormone?

Hormone derived mostly from cholesterol Signup and view all the answers

What is a peptide hormone?

Hormone composed of a polypeptide chain Signup and view all the answers

What effect will a cAMP inhibitor have on a peptide hormone-mediated signaling pathway?

It will prevent activation of protein kinases. Signup and view all the answers

What is adenylate cyclase?

An enzyme that catalyzes the conversion of ATP to cyclic AMP Signup and view all the answers

What does down-regulation refer to?

A decrease in the number of hormone receptors in response to increased hormone levels Signup and view all the answers

What is a first messenger?

The hormone that binds to a plasma membrane hormone receptor to trigger a signal transduction pathway Signup and view all the answers

What is a G-protein?

A membrane protein activated by the hormone first messenger to activate the formation of cyclic AMP Signup and view all the answers

What is a hormone receptor?

The cellular protein that binds to a hormone Signup and view all the answers

What is an intracellular hormone receptor?

A hormone receptor in the cytoplasm or nucleus of a cell Signup and view all the answers

What is phosphodiesterase (PDE)?

An enzyme that deactivates cAMP, stopping hormone activity Signup and view all the answers

What is a plasma membrane hormone receptor?

A hormone receptor on the surface of the plasma membrane of a cell Signup and view all the answers

What does up-regulation refer to?

An increase in the number of hormone receptors in response to increased hormone levels Signup and view all the answers

What hormone does drinking alcoholic beverages inhibit?

ADH release Signup and view all the answers

FSH and LH release from the anterior pituitary is stimulated by ________.

GnRH Signup and view all the answers

What hormone is produced by beta cells of the pancreas?

Insulin Signup and view all the answers

When blood calcium levels are low, PTH stimulates?

Osteoclasts Signup and view all the answers

What is acromegaly?

Condition caused by overproduction of GH in adults Signup and view all the answers

What is Addison's disease?

Disorder caused by the hyposecretion of corticosteroids Signup and view all the answers

What is adrenocorticotropic hormone (ACTH)?

Hormone released by the anterior pituitary that stimulates the adrenal cortex to release corticosteroids during the long-term stress response Signup and view all the answers

What does ACTH stand for?

Adrenocorticotropic hormone Signup and view all the answers

What is aldosterone?

Steroid hormone produced by the adrenal cortex that stimulates reabsorption of Na+ from extracellular fluids and secretion of K+. Signup and view all the answers

What is an androgen?

Male sex hormone such as testosterone Signup and view all the answers

What is antidiuretic hormone (ADH)?

Hormone produced by the hypothalamus and released by the posterior pituitary that increases water reabsorption by the kidneys Signup and view all the answers

What does ADH stand for?

Antidiuretic hormone Signup and view all the answers

What is calcitonin?

Hormone produced by the parafollicular cells of the thyroid gland that functions to lower blood Ca2+ levels and promote bone growth Signup and view all the answers

What is a corticosteroid?

Hormone released by the adrenal cortex in response to long-term stress Signup and view all the answers

What is cortisol?

Glucocorticoid produced in response to stress Signup and view all the answers

What is Cushing's disease?

Disorder caused by the hypersecretion of glucocorticoids Signup and view all the answers

What is diabetes insipidus?

Disorder caused by underproduction of ADH Signup and view all the answers

What is diabetes mellitus?

Disorder caused by low levels of insulin activity Signup and view all the answers

What is referred to as the diabetogenic effect?

Effect of GH that causes blood glucose levels to rise similar to diabetes mellitus Signup and view all the answers

What is epinephrine?

Hormone released by the adrenal medulla in response to short-term stress Signup and view all the answers

What are estrogens?

A group of steroid hormones produced by the ovaries Signup and view all the answers

What is follicle-stimulating hormone (FSH)?

Hormone produced by the anterior pituitary that stimulates gamete production Signup and view all the answers

What does FSH stand for?

Follicle-stimulating hormone Signup and view all the answers

What is gigantism?

Condition caused by overproduction of GH in children Signup and view all the answers

What is glucagon?

Hormone produced by the alpha cells of the pancreas in response to low blood sugar; functions to raise blood sugar levels Signup and view all the answers

What is a glucocorticoid?

Corticosteroid that affects glucose metabolism Signup and view all the answers

What is gluconeogenesis?

Synthesis of glucose from amino acids Signup and view all the answers

What is the glucose-sparing effect?

Effect of GH that causes tissues to use fatty acids instead of glucose as an energy source Signup and view all the answers

What is glycogenolysis?

Breakdown of glycogen into glucose Signup and view all the answers

What is goiter?

Enlargement of the thyroid gland caused by insufficient dietary iodine levels Signup and view all the answers

What is a gonadotropin?

Hormone that regulates the gonads, including FSH and LH Signup and view all the answers

What is growth hormone (GH)?

Hormone produced by the anterior pituitary that promotes protein synthesis and body growth Signup and view all the answers

What does GH stand for?

Growth hormone Signup and view all the answers

What is growth hormone-inhibiting hormone (GHIH)?

Hormone produced by the hypothalamus that inhibits growth hormone production Signup and view all the answers

What does GHIH stand for?

Growth hormone-inhibiting hormone Signup and view all the answers

What is growth hormone-releasing hormone (GHRH)?

Hormone released by the hypothalamus that triggers the release of GH Signup and view all the answers

What does GHRH stand for?

Growth hormone-releasing hormone Signup and view all the answers

What is hyperglycemia?

High blood sugar level Signup and view all the answers

What is hyperthyroidism?

Overactivity of the thyroid gland Signup and view all the answers

What is hypoglycemia?

Low blood sugar level Signup and view all the answers

What is hypothyroidism?

Underactivity of the thyroid gland Signup and view all the answers

What is insulin?

Hormone produced by the beta cells of the pancreas in response to high blood glucose levels; functions to lower blood glucose levels Signup and view all the answers

What is insulin-like growth factor (IGF)?

Growth-promoting protein produced by the liver Signup and view all the answers

What does IGF stand for?

Insulin-like growth factor Signup and view all the answers

What is a mineralocorticoid?

Corticosteroid that affects ion and water balance Signup and view all the answers

What is norepinephrine?

Hormone released by the adrenal medulla in response to short-term stress Signup and view all the answers

What is an osmoreceptor?

Receptor in the hypothalamus that monitors the concentration of electrolytes in the blood Signup and view all the answers

What is oxytocin?

Hormone released by the posterior pituitary to stimulate uterine contractions during childbirth Signup and view all the answers

What is parathyroid hormone (PTH)?

Hormone produced by the parathyroid glands in response to low blood Ca2+ levels; functions to raise blood Ca2+ levels Signup and view all the answers

What does PTH stand for?

Parathyroid hormone Signup and view all the answers

What is pituitary dwarfism?

Condition caused by underproduction of GH in children Signup and view all the answers

What is prolactin (PRL)?

Hormone produced by the anterior pituitary that stimulates milk production Signup and view all the answers

What does PRL stand for?

Prolactin Signup and view all the answers

What is prolactin-inhibiting hormone?

Hormone produced by the hypothalamus that inhibits the release of prolactin Signup and view all the answers

What is prolactin-releasing hormone?

Hormone produced by the hypothalamus that stimulates the release of prolactin Signup and view all the answers

What is renin?

Enzyme produced by the juxtaglomerular apparatus of the kidneys that reacts with angiotensinogen to cause the release of aldosterone Signup and view all the answers

What is thyroglobulin?

Glycoprotein found in the thyroid that is converted into thyroid hormone Signup and view all the answers

What is thyroid-stimulating hormone (TSH)?

Hormone produced by the anterior pituitary that controls the release of T3 and T4 from the thyroid gland Signup and view all the answers

What does TSH stand for?

Thyroid-stimulating hormone Signup and view all the answers

What is thyroxine (T4)?

Thyroid hormone containing 4 iodines that controls the basal metabolic rate Signup and view all the answers

What is tetraiodothyronine (T4)?

Thyroxine Signup and view all the answers

What is triiodothyronine (T3)?

Thyroid hormone containing 3 iodines that controls the basal metabolic rate Signup and view all the answers

What does T3 stand for?

Triiodothyronine Signup and view all the answers

What stimulates the release of insulin from the pancreas?

A rise in blood glucose levels triggers insulin release. Signup and view all the answers

What mechanism of hormonal stimulation would be affected if signaling from the hypothalamus was blocked?

Hormonal and neural stimuli Signup and view all the answers

What are hormonal stimuli?

Release of a hormone in response to another hormone Signup and view all the answers

What are humoral stimuli?

Control of hormone release in response to changes in extracellular fluids Signup and view all the answers

What are neural stimuli?

Stimulation of endocrine glands by the nervous system Signup and view all the answers

Which endocrine glands are associated with the kidneys?

Adrenal glands Signup and view all the answers

Which of the following hormones is not produced by the anterior pituitary?

Oxytocin Signup and view all the answers

What is the adrenal cortex?

Outer portion of adrenal glands that produces corticosteroids Signup and view all the answers

What is the adrenal gland?

Endocrine glands associated with the kidneys Signup and view all the answers

What is the adrenal medulla?

Inner portion of adrenal glands that produces epinephrine and norepinephrine Signup and view all the answers

What is an alpha cell?

Endocrine cell of the pancreatic islets that produces the hormone glucagon Signup and view all the answers

What is the anterior pituitary?

Portion of the pituitary gland that produces six hormones Signup and view all the answers

What is atrial natriuretic peptide (ANP)?

Hormone produced by the heart to reduce blood volume, pressure, and Na+ concentration Signup and view all the answers

What is a beta cell?

Endocrine cell of the pancreatic islets that produces the hormone insulin Signup and view all the answers

What is colloid?

Fluid inside the thyroid gland that contains the glycoprotein thyroglobulin Signup and view all the answers

What is an endocrine gland?

Gland that secretes hormones into the surrounding interstitial fluid Signup and view all the answers

What is erythropoietin (EPO)?

Hormone produced by the kidneys to stimulate red blood cell production in the bone marrow Signup and view all the answers

What is the hypophyseal portal system?

System of blood vessels that carries hormones from the hypothalamus to the anterior pituitary Signup and view all the answers

What are the islets of Langerhans?

Endocrine cells of the pancreas Signup and view all the answers

What is the isthmus?

Tissue mass that connects the two lobes of the thyroid gland Signup and view all the answers

What is leptin?

Hormone produced by adipose tissue that promotes feelings of satiety and reduces hunger Signup and view all the answers

Study Notes

Hormone Classification and Types

Peptide hormones consist of chains of amino acids and are characterized by <4 amino acids.
Lipid-derived hormones can diffuse through plasma membranes due to their hydrophobic nature, primarily derived from cholesterol.
Amino acid-derived hormones originate from individual amino acids, playing essential roles in signaling.
Hormones that primarily act as peptide hormones are composed of polypeptide chains.

Signaling Mechanisms

First messengers are hormones that bind to plasma membrane receptors, initiating signal transduction pathways.
Adenylate cyclase converts ATP to cyclic AMP, a crucial step in many hormone signaling pathways.
G-proteins are activated by first messengers and facilitate the production of cyclic AMP.
cAMP inhibitors block the activation of protein kinases, halting the signaling pathway initiated by peptide hormones.

Hormone Receptors and Regulation

Hormone receptors can be classified as plasma membrane receptors (on the cell surface) or intracellular receptors (in the cytoplasm or nucleus).
Down-regulation occurs when increased hormone levels lead to a decrease in receptor numbers, while up-regulation is the opposite, increasing receptor numbers in response to elevated hormone levels.

Specific Hormones and Their Functions

Alcohol consumption inhibits the release of antidiuretic hormone (ADH), increasing urine output.
Gonadotropin-releasing hormone (GnRH) stimulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary.
Insulin, produced by beta cells in the pancreas, lowers blood glucose levels, while glucagon, from alpha cells, raises it.

Calcium and Bone Metabolism

Parathyroid hormone (PTH) is secreted when blood calcium levels are low and stimulates osteoclast activity to increase blood calcium.
Calcitonin reduces blood calcium levels and promotes bone growth, secreted by parafollicular cells in the thyroid gland.

Acromegaly results from GH overproduction in adults, while gigantism occurs in children due to excessive GH.
Addison's disease is caused by hyposecretion of corticosteroids, while Cushing's disease results from excessive glucocorticoids.
Diabetes insipidus occurs because of underproduction of ADH, and diabetes mellitus arises from low insulin activity.

Hormone Response and Production Mechanisms

Control of hormone release can occur through:
- Humoral stimuli: changes in blood composition (e.g., glucose levels).
- Hormonal stimuli: release triggered by other hormones.
- Neural stimuli: direct nervous system stimulation of endocrine glands.

Endocrine Glands Overview

The adrenal cortex produces corticosteroids; the adrenal medulla produces epinephrine and norepinephrine.
The anterior pituitary secretes six hormones, including FSH, LH, and adrenocorticotropic hormone (ACTH), which stimulates corticosteroid release during stress.
The thyroid gland produces thyroxine (T4) and triiodothyronine (T3), which control metabolic rates.

Additional Hormonal Actions and Functions

Aldosterone, a mineralocorticoid, promotes sodium reabsorption and potassium secretion.
Leptin, produced by adipose tissue, helps regulate appetite by promoting satiety.
Erythropoietin (EPO) stimulates red blood cell production in response to low oxygen levels, produced by the kidneys.

Important Concepts in Endocrinology

Hormones are signaling molecules released into the bloodstream to regulate various physiological processes.
Understanding hormone pathways and their effects is crucial for diagnosing and treating endocrine disorders.
Hormonal interactions can involve complex feedback loops, illustrating the intricacies of the endocrine system.

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Description

Explore the various types of hormones and their classification, including peptide, lipid-derived, and amino acid-derived hormones. Understand the signaling mechanisms involved, such as the role of first messengers, cyclic AMP, and G-proteins. This quiz will enhance your understanding of how hormones function and interact with their receptors.