Untitled Quiz
45 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which of the following is a key difference between the endocrine and nervous systems in maintaining homeostasis?

  • The endocrine system directly innervates target tissues, unlike the nervous system which relies on neurotransmitters.
  • The nervous system responds rapidly with short-lived effects, while the endocrine system responds slowly with long-lasting effects. (correct)
  • Only the nervous system utilizes feedback loops to regulate body functions.
  • The endocrine system uses electrical signals for communication, while the nervous system uses chemical signals.

In a negative feedback loop, what is the primary effect of the control mechanism when a parameter deviates from its set point?

  • To counteract the initial change, bringing the parameter back toward the set point. (correct)
  • To amplify the initial change, pushing the parameter further away from the set point.
  • To ignore the change, allowing the parameter to fluctuate randomly.
  • To maintain the parameter at the new level, establishing a new set point.

Which component of a homeostatic control system is responsible for detecting changes in the internal or external environment?

  • Effectors
  • Control center
  • Receptors (correct)
  • Hormones

What is the main outcome of a positive feedback loop?

<p>Amplifying the initial change in a parameter, leading to a greater deviation from the original state. (A)</p> Signup and view all the answers

Which of the following is an example of the 'nature of message' used by the nervous system for control and coordination?

<p>Action potentials and neurotransmitters. (D)</p> Signup and view all the answers

If body temperature decreases, what would a negative feedback loop trigger?

<p>Mechanisms to increase body temperature. (C)</p> Signup and view all the answers

The endocrine system and nervous system both use chemical messengers for intercellular communication. What distinguishes the endocrine system's method?

<p>It uses slower transmission via hormones released into the bloodstream. (C)</p> Signup and view all the answers

Which of the following is NOT a basic component of homeostatic control systems?

<p>Stimulus (B)</p> Signup and view all the answers

A scientist discovers a new hormone that, when introduced to a cell culture, leads to an increase in protein synthesis and a decrease in membrane permeability. Which of the following best explains this observation?

<p>The hormone likely binds to an intracellular receptor, leading to altered gene transcription that enhances protein synthesis and reduces membrane permeability. (D)</p> Signup and view all the answers

A researcher is studying a hormone that affects both liver cells and muscle cells. In liver cells, the hormone promotes glycogen breakdown, while in muscle cells, it enhances glucose uptake. What is the most likely explanation for these different responses to the same hormone?

<p>The hormone binds to different types of receptors in liver and muscle cells, initiating distinct signaling pathways. (B)</p> Signup and view all the answers

Which of the following is the most direct requirement for a cell to be considered a target cell for a specific hormone?

<p>The cell must possess specific intracellular or membrane proteins that act as receptors for the hormone. (A)</p> Signup and view all the answers

A pharmaceutical company is developing a drug to mimic the effects of a particular hormone. To ensure the drug has the desired effect, it should:

<p>Specifically bind to the receptors of the hormone on the target cells. (B)</p> Signup and view all the answers

A patient has a condition where their immune system is attacking the hormone receptors on their target cells. What is the most likely consequence of this condition?

<p>Reduced sensitivity of the target cells to the specific hormone, leading to hormone resistance. (C)</p> Signup and view all the answers

Which of the following statements accurately distinguishes between endocrine and exocrine glands?

<p>Endocrine glands secrete hormones directly into the bloodstream or interstitial fluid, while exocrine glands secrete products into ducts or onto body surfaces. (B)</p> Signup and view all the answers

An organ contains both exocrine and endocrine tissues. How is it classified within the endocrine system?

<p>Only the endocrine portion is considered part of the endocrine system. (B)</p> Signup and view all the answers

A chemical messenger released from a cell acts on the same cell that secreted it. This type of signaling is best described as:

<p>Autocrine. (B)</p> Signup and view all the answers

Which of the following organs is exclusively an endocrine gland?

<p>Adrenal (C)</p> Signup and view all the answers

Which of the following is NOT a characteristic of circulating hormones?

<p>They are a type of local hormone (D)</p> Signup and view all the answers

Which of the following best explains why the endocrine system is considered a diffuse system?

<p>Many different organs and tissues throughout the body contain endocrine cells. (B)</p> Signup and view all the answers

Considering the roles of different glands, which gland's primary function is to adjust regulated parameters in the body?

<p>Effector (B)</p> Signup and view all the answers

Interleukin-2 (IL-2) is a local hormone that can stimulate both the cell that secreted it and neighboring cells. This type of signaling is best described as:

<p>Autocrine and paracrine signaling. (A)</p> Signup and view all the answers

Which of the following scenarios best illustrates a hormone's role in maintaining homeostasis?

<p>The regulation of sleep-wake cycles by melatonin secreted from the pineal gland in response to light exposure. (D)</p> Signup and view all the answers

A researcher is studying a newly discovered hormone. Initial findings reveal that this hormone is synthesized from cholesterol. Based on this information, the hormone is most likely a:

<p>Steroid hormone. (C)</p> Signup and view all the answers

Why do lipid-soluble hormones require transport proteins in the bloodstream, while water-soluble hormones do not?

<p>Lipid-soluble hormones are hydrophobic and require transport proteins to be carried in the aqueous environment of the blood. (A)</p> Signup and view all the answers

Which of the following is an example of a hormone that is NOT derived from an amino acid?

<p>Cortisol (A)</p> Signup and view all the answers

A patient has a condition where their biogenic amine hormones are being excessively metabolized. Which class of hormones would drugs need to target to prevent their degradation?

<p>Hormones derived from tyrosine, tryptophan and histidine. (D)</p> Signup and view all the answers

A scientist is investigating a signaling pathway and observes that a particular hormone leads to a rapid, widespread response in multiple target tissues. Which characteristic of hormones best explains this observation?

<p>Hormones produce wide-reaching coordinated effects on multiple target tissues. (A)</p> Signup and view all the answers

How do thyroid hormones, being lipid-soluble, differ in their mechanism of action compared to peptide hormones, which are water-soluble?

<p>Thyroid hormones directly influence gene transcription, while peptide hormones typically use second messenger systems. (D)</p> Signup and view all the answers

Which of the following best explains how hormones like ADH (antidiuretic hormone) and oxytocin, which are peptide hormones, can have such specific effects despite traveling throughout the entire bloodstream?

<p>Only target cells with the appropriate receptors can bind the hormone and initiate a response. (B)</p> Signup and view all the answers

How do steroid hormones typically affect target cells?

<p>By diffusing into the cell and binding to intracellular receptors, altering gene expression and protein synthesis. (B)</p> Signup and view all the answers

What is a primary difference in the action of peptide hormones compared to steroid hormones?

<p>Peptide hormones act more quickly than steroid hormones. (D)</p> Signup and view all the answers

Which cellular process do both insulin's effect on hepatocytes and adipocytes have in common?

<p>Stimulation of anabolic processes. (A)</p> Signup and view all the answers

Why do water-soluble hormones, such as peptide hormones, NOT require transport proteins in the blood?

<p>They are able to dissolve readily in the blood. (A)</p> Signup and view all the answers

How does cAMP function in the mechanism of peptide hormone action?

<p>It serves as a second messenger to alter the phosphorylation state of existing proteins. (C)</p> Signup and view all the answers

What is the immediate consequence of a peptide hormone binding to a cell surface receptor?

<p>Initiation of an enzyme cascade via second messengers. (D)</p> Signup and view all the answers

A pharmaceutical company is designing a drug that mimics a steroid hormone. What intracellular component should this drug target to elicit a response?

<p>Intracellular receptors. (D)</p> Signup and view all the answers

If a researcher wants to study the immediate effects of a hormone on a cell, which type of hormone would be most appropriate to use?

<p>A peptide hormone that activates second messengers. (A)</p> Signup and view all the answers

A key characteristic of water-soluble hormones is their inability to cross the cell membrane directly. How do these hormones typically initiate a response inside the target cell?

<p>By triggering the production of intracellular second messengers. (C)</p> Signup and view all the answers

Which of the following is the most direct role of cAMP as a second messenger?

<p>To activate protein kinases. (A)</p> Signup and view all the answers

A pharmaceutical company is designing a drug to mimic the effects of a specific hormone. The hormone primarily acts by increasing intracellular calcium ion concentrations. Which of the following mechanisms would be the most effective target for this drug?

<p>Stimulating the release of calcium ions from intracellular stores. (C)</p> Signup and view all the answers

Norepinephrine stimulates different responses in different target cells because:

<p>It binds to different types of receptors that generate different second messengers. (A)</p> Signup and view all the answers

How do protein phosphatases contribute to the regulation of cellular responses initiated by second messengers?

<p>By removing phosphate groups from proteins, thus reversing the effects of kinases. (D)</p> Signup and view all the answers

Following the binding of a water-soluble hormone to its receptor, a G protein is activated. What is the primary role of this activated G protein?

<p>To activate adenylate cyclase, leading to cAMP production. (A)</p> Signup and view all the answers

A cell is treated with a drug that inhibits the activity of phosphodiesterase. What immediate effect would this drug have on cellular signaling pathways that involve cAMP?

<p>Prolonged elevation of cAMP levels. (D)</p> Signup and view all the answers

Why can different target cells respond differently to the same hormone?

<p>Because different target cells possess different receptors for the hormone and utilize different signal transduction pathways. (B)</p> Signup and view all the answers

Flashcards

Endocrine System

Glands that release hormones into the bloodstream to regulate various bodily functions.

Nervous System

A system using electrical signals and neurotransmitters for rapid communication.

Hormones

Hormones are chemical messengers secreted by endocrine glands.

APs & NTs

APs & NTs are the messengers of the nervous system.

Signup and view all the flashcards

Homeostasis

Maintaining a stable internal environment.

Signup and view all the flashcards

Negative Feedback Loop

A control mechanism where the response opposes the initial change, bringing the variable back to its set point.

Signup and view all the flashcards

Positive Feedback Loop

A control mechanism where the response amplifies the initial change, moving the variable further away from its set point.

Signup and view all the flashcards

Receptor (Homeostasis)

A component that detects changes in the internal or external environment.

Signup and view all the flashcards

Effector

Component that adjusts the regulated parameter in a feedback loop.

Signup and view all the flashcards

Exocrine Glands

Glands that secrete products into ducts or lumens or onto body surfaces.

Signup and view all the flashcards

Endocrine Glands

Glands that secrete products into the interstitial fluid or blood.

Signup and view all the flashcards

Local Hormones

Hormones that act locally on neighboring cells (paracrine) or on the same cell that secreted them (autocrine) without entering the bloodstream.

Signup and view all the flashcards

Paracrine

Act on neighboring cells.

Signup and view all the flashcards

Autocrine

Act on the same cell that secreted them.

Signup and view all the flashcards

Hormones Definition

Chemical messengers (mediator molecules).

Signup and view all the flashcards

Circulating Hormones

Diffuse into interstitial fluid and then enter the bloodstream to reach target cells throughout the body.

Signup and view all the flashcards

Steroid Hormones

Hormones derived from cholesterol; examples include cortisol, testosterone, and estrogen.

Signup and view all the flashcards

Thyroid Hormones

Hormones made from a tyrosine ring with attached iodines; very lipid-soluble.

Signup and view all the flashcards

Peptide & Protein Hormones

Hormones composed of chains of amino acids; includes hypothalamic hormones, ADH, insulin, and glucagon.

Signup and view all the flashcards

Biogenic Amines

Hormones that are modified amino acids; examples include catecholamines (NE, epinephrine, dopamine).

Signup and view all the flashcards

Hormone Functions

Released from glands in response to changes and produce effects on multiple target tissues.

Signup and view all the flashcards

Hormones and Homeostasis

Help maintain stable conditions in the body.

Signup and view all the flashcards

Hormone Solubility

Water-soluble hormones freely dissolve in body fluids. Lipid-soluble hormones need transport proteins.

Signup and view all the flashcards

Hormone Receptors

Proteins on or in target cells that bind to specific hormones, triggering a response.

Signup and view all the flashcards

Hormone Transport

Hormones leave cells via exocytosis or diffusion, travel in blood freely or bound to proteins, and bind to receptors on/in target cells.

Signup and view all the flashcards

Cellular Response to Hormones

Synthesis of new molecules, alteration of existing molecules, changes in membrane permeability, or altered reaction rates.

Signup and view all the flashcards

Second Messengers

Water-soluble hormones that trigger intracellular effects.

Signup and view all the flashcards

Examples of Second Messengers

cAMP, calcium ions, and cGMP are common examples.

Signup and view all the flashcards

Variable Hormone Response

A hormone can activate different responses in different cells.

Signup and view all the flashcards

Adenylate Cyclase

Enzyme that converts ATP to cAMP, amplifying cellular signals.

Signup and view all the flashcards

Phosphodiesterase

An enzyme that inactivates cAMP.

Signup and view all the flashcards

Protein Kinases

Enzymes that add phosphate groups to proteins.

Signup and view all the flashcards

Protein Phosphatases

Enzymes that remove phosphate groups from proteins.

Signup and view all the flashcards

Receptors and Second messengers

Different receptors generate different second messengers -> different cellular responses.

Signup and view all the flashcards

Insulin's Effect on Hepatocytes

In liver cells, insulin promotes the production of glycogen for glucose storage.

Signup and view all the flashcards

Insulin's Effect on Adipocytes

In fat cells, insulin stimulates the synthesis of triglycerides for energy storage.

Signup and view all the flashcards

Lipid-Soluble Hormones

Hormones that can diffuse across the cell membrane and bind to intracellular receptors.

Signup and view all the flashcards

Hormone Transport Proteins

Proteins in the blood that bind to and transport hydrophobic hormones.

Signup and view all the flashcards

Steroid Hormone Mechanism

Changing the expression of specific genes within a target cell.

Signup and view all the flashcards

Water-Soluble Hormones

Hormones that bind to receptors on the cell surface.

Signup and view all the flashcards

Effect of 2nd Messengers

Altering the activity of existing proteins by adding phosphate groups.

Signup and view all the flashcards

Study Notes

  • The endocrine system is introduced.
  • Key objectives include knowing the major organs, comparing the endocrine and nervous systems, distinguishing between hormone types, and describing the role of hormones in second messenger activation.

Endocrine vs. Nervous System

  • Both systems control and coordinate body activities and use chemical messengers for intercellular communication.
  • The nervoussystem uses action potentials and neurotransmitters.
  • The endocrine system uses hormones.
  • Nervous system messages are measured in milliseconds to seconds.
  • Endocrine system messages are measured in seconds to minutes, or days to weeks.

Homeostasis

  • It is the ability to maintain a relatively stable internal state despite external changes.
  • A closed system with feedback circuits responds when a variable changes.
  • There are two types of feedback circuits: negative and positive.
  • Change triggers reversal of detected change using negative feedback loops, where changes in a monitored parameter cause the control mechanism to counteract further changes in the same direction.
  • Change triggers amplification of detected change, in a positive feedback loop/cumulative causation, where changes in a monitored parameter cause the control mechanism to amplify changes in the same direction.
  • Homeostatic control systems have three components: receptors, control center, and effector.
  • Receptors sense changes in the internal/external environment
  • The control center processes information from receptors and sends a response to effectors.
  • The effector adjusts the regulated parameter.

Exocrine vs Endocrine Glands

  • The endocrine system doesn't include exocrine glands.
  • Exocrine glands secrete products into ducts, lumens, or onto the body's outer surface.
  • Endocrine glands secrete products into interstitial fluid or blood, which diffuse into the blood.
  • Some organs have both portions, but the endocrine system only refers to the endocrine portion of an organ.

Anatomy of the Endocrine System

  • Endocrine glands include the pituitary, thyroid, parathyroid, adrenal, and pineal glands.
  • Other organs/tissues with endocrine cells include the hypothalamus, thymus, pancreas, ovaries/testes, kidneys, liver, stomach, small intestine, heart, skin, and adipose tissue.
  • The system is diffuse; any tissue/organ containing endocrine cells is part of it.

Hormones: Chemical Messengers

  • Hormones are chemical messengers released in one part of the body to regulate activity in other parts.
  • Local hormones act on neighboring cells (paracrine) or on the same cell that secreted them (autocrine) before entering the bloodstream.
  • Circulating hormones enter interstitial fluid and then the bloodstream.
  • Examples of local hormones include IL-2, which stimulates proliferation of helper T cells and activation of cytotoxic T cells, and histamine, which stimulates HCl secretion in stomach.
  • Lipid-soluble hormones bind to transport proteins for transport in body fluids.
  • Water-soluble hormones freely dissolve in body fluids.

Lipid-Soluble Hormones

  • Steroid hormones are derived from cholesterol, and have unique chemical groups attached to their structure's core.
  • Examples of steroid hormones are cortisol, testosterone, estrogens, progesterone, and aldosterone.
  • Thyroid hormones have a tyrosine ring with attached iodines and are lipid soluble.
  • Steroid and thyroid hormones can be ingested.

Water-Soluble Hormones

  • Peptide and protein hormones are chains of amino acids, including hypothalamic releasing and inhibiting hormones, ADH, oxytocin, hGH, TSH, ACTH, insulin, glucagon, and EPO.
  • Biogenic amines are modified amino acids, including catecholamines like NE, epinephrine, and dopamine, as well as serotonin, melatonin, and histamine.

Hormone Functions

  • Regulate many aspects of organ system function, released from glands upon changes, and produce effects on multiple target tissues in a wide-reaching way to help maintain homeostasis.
  • They impact ion/nutrient levels, metabolic pathways, biological clock, contraction of cardiac/smooth muscle, glandular secretion, some immune functions, growth, development, and reproduction.

Transport Mechanisms, Action & Cell Response

  • Hormones leave secretory cells by exocytosis or diffusion and travel freely or bound to transport proteins in the blood.
  • Hormones bind to cell surface receptors or receptors inside target cells.
  • Cells respond through synthesis/alteration of molecules, changes in membrane permeability, or altered reaction rates.
  • Different target cells may respond to the same hormone differently such as insulin stimulates glycogen synthesis differently in hepatocytes and stimulates triglyceride synthesis differently in Adipocytes.

Steroid Hormone Action

  • Steroid hormones leave a secretory cell by diffusion.
  • Require transport proteins in blood.
  • Diffuse freely into target cells where receptors are typically intracellular.
  • Their effect is to change the level of specific gene expression.
  • The response by target cells is relatively slow.

Peptide Hormone Action

  • Peptide hormones leave a secretory cell by exocytosis and do not require transport proteins in blood.
  • Bind to cell surface receptors, typically evoking changes in activity of existing proteins via second messengers like c-AMP, where phosphorylation state is altered.
  • The response by target cells is very fast. .

Second Messengers

  • Water-soluble (peptide) hormones ("first messenger") bind to cell surface receptors and produce intracellular “second messengers" at different levels
  • Examples include cAMP, calcium ions, and cGMP.
  • The same hormone may use different second messengers in different target cells.
  • Second messengers initiate a cascade of biochemical reactions (often involving phosphorylation or dephosphorylation) within target cells.
  • Hormone receptors create different second messangers, and can cause completely different responses in a target cell.
  • Hormones with this system include Adrenocorticotropic hormone (ACTH), Angiotensin II, Calcitonin, Catecholamines, Follicle-stimulating hormone (FSH) etc.

Studying That Suits You

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

Quiz Team

Related Documents

Human Anatomy & Physiology II (PSIO202) Endocrine System Introduction PDF

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser