Endocrine Hormones Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a preprohormone primarily composed of?

Amine hormone derivatives

Single amino acid modifications

Active hormone and signal sequence

Large inactive protein with peptide hormone copies (correct)

How is the activity of peptide hormones primarily terminated in the body?

Through competitive binding to other receptors

By the formation of intracellular signaling complexes

By degradation through plasma enzymes (correct)

By modification in the liver

Which hormone classification is derived from cholesterol?

Protein fragments

Steroid hormones (correct)

Amine hormones

Peptide hormones

What occurs during post-translational modification of peptide hormones?

Conversion of prohormone into an active hormone Signup and view all the answers

What initiates the release of peptide hormone-containing secretory vesicles?

Calcium-dependent exocytosis Signup and view all the answers

What type of hormones are considered to be modifications of single amino acids?

Amine hormones Signup and view all the answers

Which of the following components is NOT part of the endoplasmic reticulum's process for peptide hormones?

Formation of amine hormones Signup and view all the answers

What term describes the process of releasing all peptide fragments from prohormones into the extracellular fluid?

Co-secretion Signup and view all the answers

Which cell type in the islets of Langerhans is primarily responsible for insulin production?

Beta cells Signup and view all the answers

What role does glucagon play in the body?

Stimulates glycogen breakdown and glucose synthesis Signup and view all the answers

In a fed state, which of the following occurs due to the dominance of insulin?

Net anabolism in the body Signup and view all the answers

What is the primary function of D cells in the islets of Langerhans?

Secrete somatostatin Signup and view all the answers

What happens to insulin and glucagon levels shortly after a meal?

Insulin increases and glucagon decreases Signup and view all the answers

How does the body manage plasma glucose levels during fasting?

Utilizing glycogen for glucose synthesis Signup and view all the answers

Which hormone is primarily responsible for the conversion of excess glucose into fat?

Insulin Signup and view all the answers

What is the typical fasting plasma glucose level maintained in a normal person?

90 mg/dL Signup and view all the answers

Which structure is responsible for the secretion of neurohormones in the brain?

Posterior pituitary Signup and view all the answers

What are the two neurohormones stored and released by the posterior pituitary?

Oxytocin and vasopressin Signup and view all the answers

What initiates the release of neurohormones from the posterior pituitary?

Electrical signals from the hypothalamus Signup and view all the answers

How do neurohormones travel after being released into the blood?

They are dissolved in plasma without any transport mechanism Signup and view all the answers

What is the primary function of vasopressin in the body?

Regulating water balance Signup and view all the answers

What is the primary purpose of binding steroid hormones to protein carriers?

To extend their half-life in the blood Signup and view all the answers

In what part of the pituitary is oxytocin synthesized?

Hypothalamus Signup and view all the answers

Where are steroid hormone receptors primarily located within the target cells?

In the cytoplasm or nucleus Signup and view all the answers

What are the amino acid compositions of oxytocin and vasopressin?

Nine amino acids each Signup and view all the answers

What effect do steroid hormones have once they bind to their receptors in the nucleus?

They act as transcription factors that may activate or repress genes Signup and view all the answers

What is the primary role of oxytocin during labor and breastfeeding?

Controlling ejection of milk and uterine contractions Signup and view all the answers

Which statement accurately describes the lag time associated with steroid hormones?

It could last up to 90 minutes Signup and view all the answers

Which substances are the amino acid-derived hormones primarily created from?

Tryptophan and tyrosine Signup and view all the answers

What is the role of the output signal in endocrine reflex pathways?

To act as a hormone or neurohormone Signup and view all the answers

Which hormone is derived from tryptophan?

Melatonin Signup and view all the answers

What factor impacts the constant ratio of unbound to bound steroid hormones in the plasma?

The law of mass action Signup and view all the answers

What is the primary effect of PTH on phosphate reabsorption in the kidneys?

Reduces phosphate reabsorption Signup and view all the answers

Which hormone primarily facilitates the intestinal absorption of calcium?

Calcitriol Signup and view all the answers

What triggers the secretion of calcitonin?

Increased plasma calcium concentrations Signup and view all the answers

How does PTH indirectly contribute to calcium absorption in the intestines?

By stimulating calcitriol synthesis Signup and view all the answers

Which of the following is NOT a function of calcitriol?

Increases renal excretion of calcium Signup and view all the answers

Which demographic group may need vitamin D supplementation due to insufficient sunlight exposure?

Individuals living above 37 degrees latitude north or below 37 degrees south Signup and view all the answers

What happens when the plasma calcium concentration increases?

Calcitonin secretion increases Signup and view all the answers

What is the role of prolactin in calcium balance during lactation?

Stimulates calcitriol synthesis Signup and view all the answers

What is the primary necessity for obtaining essential amino acids?

They must be obtained through dietary sources. Signup and view all the answers

What effect does cortisol have on growth in children?

It inhibits growth due to catabolic effects. Signup and view all the answers

At what point in life does peak secretion of growth hormone typically occur?

During teenage years Signup and view all the answers

What is the role of growth hormone-releasing hormone (GHRH)?

Stimulating the release of growth hormone. Signup and view all the answers

How does growth hormone affect secretion of insulin-like growth factors?

It stimulates their secretion. Signup and view all the answers

Which organ is primarily responsible for the secretion of growth hormone?

Anterior pituitary Signup and view all the answers

What function does the growth hormone-binding protein serve in the bloodstream?

Protecting growth hormone from urine filtration. Signup and view all the answers

Which of the following factors is NOT a stimulus for growth hormone release?

Genetic modifications Signup and view all the answers

Study Notes

Endocrine System Overview

Endocrinology is the study of hormones
Hormones are chemical messengers secreted into the bloodstream by specialized cells
Hormones control long-term, ongoing body functions, including growth, development, metabolism, internal environment regulation, and reproduction
Hormones act on target cells in three ways: controlling enzymatic reactions, controlling ion or molecule transport across cell membranes, or controlling gene expression and protein synthesis
A hormone is a chemical secreted by a cell or group of cells into the blood to transport it to a distant target, where it exerts its effect at very low concentrations

What Makes a Chemical a Hormone?

Hormones are secreted by cells, not just classic endocrine glands
Endocrine cells, neurons (neurohormones), and immune cells (cytokines) can secrete hormones
Hormones are secreted into the bloodstream; however, the term ectohormone is given to signal molecules secreted into the external environment (ex. pheromones)
Some chemical signals in the blood may not be considered hormones because they need to be present in high concentrations to have an effect
Hormones act on target cells at very low concentrations (nanomolar to picomolar)

Hormone Action and Termination

Hormones bind to target cell receptors to initiate biochemical responses
Hormone effects can vary depending on the tissue and developmental stage, or a hormone may have no effect in a certain cell
Hormones must be terminated for the body to respond appropriately to changes in the body
Hormones are terminated by limiting secretion, removing/inactivating circulating hormones in the blood, or terminating hormone activity in target cells
Hormones are degraded into inactive metabolites by enzymes located primarily in the liver and kidneys
Hormones' half-lives indicate how long the hormone is active in the body

Classification of Hormones

Hormones are classified into three main types: peptide/protein hormones, steroid hormones, and amino acid-derived (amine) hormones
Peptide/protein hormones are chains of amino acids
Steroid hormones are derived from cholesterol
Amine hormones are modifications of tyrosine or tryptophan

Peptide/Protein Hormones

Synthesis, storage, and release of peptide hormones into membrane-bound secretory vesicles is similar to other proteins
The initial peptide is a large inactive protein called a preprohormone
Preprohormones undergo post-translational modification in the Golgi apparatus to become active hormones and other fragments

Steroid Hormones

Steroid hormones are derived from cholesterol and have a similar chemical structure
Hormone production for steroid hormones is located in specific organs, unlike peptide hormones
Steroid hormones are not very soluble in plasma and other body fluids
Most steroid hormones bind to carrier proteins in the blood, extending their half-lives

Cellular Mechanism of Action of Steroid Hormones

Steroid hormone receptors are found within the cell, in either the cytoplasm or nucleus
Steroid receptors bind to hormones and act as transcription factors in the nucleus
Steroid hormone effects generally take a longer time because they affect gene activity
Steroid hormones do not mediate rapid reflex pathways

Additional Hormone Interactions

Three main types of hormone interactions: synergism, permissiveness, antagonism
Synergism: combined effect of multiple hormones exceeding the additive sum of individual effects
Permissiveness: one hormone enabling another hormone's full effect
Antagonism: two hormones having opposite effects

Homeostatic Control of Metabolism and the Role of Hormones

The ratio of insulin and glucagon influences an individual's hour-to-hour metabolic state
Insulin dominates during the fed state, promoting anabolism by storing glucose as glycogen or fat
Glucagon dominates during the fasted state, promoting catabolism of glycogen and other storage sources of glucose
Glucagon has more significant metabolic effects when blood glucose levels are low

Endocrine Response to Hypoglycemia/Plasma Glucose Hormones

Glucagon, released when glucose is low, promotes glycogenolysis and gluconeogenesis to replenish plasma glucose
The ratio of insulin to glucagon dictates the direction of metabolism; both play roles in maintaining blood glucose levels

Adrenal Glucocorticoids

Adrenal glands sit atop kidneys, comprised of cortex and medulla
Medulla secretes catecholamines (mostly norepinephrine) in response to stress
Cortex secretes steroid hormones including aldosterone (mineralocorticoid), glucocorticoids, and sex hormones
Cortisol is the major glucocorticoid, impacting glucose metabolism, immunology, and stress response; a prime example of a stress hormone

Thyroid Hormones

Located in the neck, thyroid gland contains follicular and C cells
Follicular cells secrete thyroid hormones, essential for growth and development (especially in children)
Thyroid hormones are made from tyrosine and iodine
Thyroid stimulating hormone (TSH) from the anterior pituitary, regulates thyroid hormone synthesis and secretion

Growth Hormone

Growth in humans is continuous but not consistently so across different periods in life (ex. adolescence)
Growth hormone (GH) promotes protein synthesis and bone and tissue growth
Several factors influence growth hormone, including: hormones other than GH, diet, genetics, and lack of stress

Calcium Balance

Most calcium is stored in bones, however, nonbone calcium, found in extracellular and intracellular fluids, is crucial to physiological functioning
Several hormones regulate calcium levels within the body.

Hormones and Their Action Pathways

Specific hormones have their own distinct pathways for signaling and eliciting a response; all hormones bind to specific receptors
Hormones can affect many tissues and organs at once through complex interactions
Different types of hormones signal through different pathways

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on endocrine hormones and their functions in the body. This quiz covers key concepts related to peptide hormones, their synthesis, and roles within the endocrine system. Perfect for those studying biology or health sciences.