Endocrine System Overview
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Questions and Answers

Which hormone is secreted by the parathyroid glands in response to declining blood calcium levels?

  • Thyroid hormone
  • Corticosteroid
  • Parathyroid hormone (correct)
  • Calcitonin

    • What triggers the endocrine glands to synthesize and release hormones?

  • Only hormonal stimuli
  • Humoral, neural, and hormonal stimuli (correct)
  • Only humoral stimuli
  • Only neural stimuli

    • How do the effects of hormones on target organs influence further hormone release?

  • They only have an immediate effect
  • They have no impact on hormone release
  • They can inhibit further hormone release (correct)
  • They always increase hormone release

    • What is one example of a function that the proteins synthesized from mRNA might serve?

    <p>Metabolic activities or structural purposes</p> Signup and view all the answers

    What type of stimulus changes blood levels of ions and nutrients to stimulate hormone secretion?

    <p>Humoral stimuli</p> Signup and view all the answers

    What is the role of the sympathetic nervous system in hormone release?

    <p>It stimulates the adrenal medulla to secrete catecholamines.</p> Signup and view all the answers

    Which factor does NOT influence target cell activation?

    <p>Type of hormone released</p> Signup and view all the answers

    How does the nervous system interact with endocrine functions during stress?

    <p>It can override normal endocrine controls.</p> Signup and view all the answers

    Which statement about hormonal stimuli is accurate?

    <p>They stimulate endocrine organs to release their hormones.</p> Signup and view all the answers

    What differentiates target cells in terms of receptor specificity?

    <p>Some hormones affect all body cells, while others are specific.</p> Signup and view all the answers

    What is the correct order of steps in the cyclic AMP (cAMP) signaling mechanism?

    <p>Hormone binds to receptor, activates G protein, activates adenylate cyclase, converts ATP to cAMP, activates protein kinases.</p> Signup and view all the answers

    Where are the receptors for lipid-soluble hormones typically located?

    <p>In the cytoplasm or nucleus of target cells.</p> Signup and view all the answers

    Which of the following is NOT a characteristic of the cAMP signaling mechanism?

    <p>It requires lipid-soluble hormones to function.</p> Signup and view all the answers

    What is the role of phosphodiesterase in the cAMP signaling pathway?

    <p>To degrade cAMP and halt the signaling cascade.</p> Signup and view all the answers

    Which process does insulin employ to trigger cellular responses?

    <p>Tyrosine kinase autophosphorylation.</p> Signup and view all the answers

    What is a major difference between autocrines and paracrines?

    <p>Autocrines act on the same cell that secreted them, while paracrines act on nearby cells.</p> Signup and view all the answers

    Which second messenger is produced by the activation of adenylate cyclase?

    <p>cAMP.</p> Signup and view all the answers

    Which signaling mechanism utilizes phosphatidyl inositol bisphosphate?

    <p>PIP2-calcium signaling pathway.</p> Signup and view all the answers

    What feature distinguishes amino acid-based hormones from lipid-soluble hormones?

    <p>Amino acid-based hormones are always water-soluble.</p> Signup and view all the answers

    What occurs during up-regulation in target cells?

    <p>Cells form more receptors in response to low hormone levels.</p> Signup and view all the answers

    Which statement describes the behavior of hormones in circulation?

    <p>Steroids and thyroid hormones are not water soluble and require plasma proteins as carriers.</p> Signup and view all the answers

    What is an example of synergism in hormonal action?

    <p>Glucagon and epinephrine both stimulating glucose release from the liver.</p> Signup and view all the answers

    Which factor does NOT influence the concentration of circulating hormones?

    <p>Duration of receptor activation.</p> Signup and view all the answers

    How does the half-life of a hormone impact its duration of activity?

    <p>Half-life determines how quickly hormone effects dissipate.</p> Signup and view all the answers

    What happens during down-regulation at target cells?

    <p>Cells lose receptors due to persistently high levels of hormone.</p> Signup and view all the answers

    Which of the following hormones operate under permissive effects?

    <p>Reproductive hormones necessitating thyroid hormones to exert their effects.</p> Signup and view all the answers

    What term describes hormones that oppose each other's actions?

    <p>Antagonistic hormones</p> Signup and view all the answers

    Which of the following correctly describes how hormones are classified?

    <p>Based on their solubility in water and their chemical structure</p> Signup and view all the answers

    What is the primary function of the endocrine system?

    <p>To coordinate and integrate cellular activities via hormones</p> Signup and view all the answers

    Which type of hormone is lipid-soluble and can cross the plasma membrane?

    <p>Steroid hormones</p> Signup and view all the answers

    Which type of gland produces hormones that enter circulation directly?

    <p>Endocrine glands</p> Signup and view all the answers

    Which of the following describes the way water-soluble hormones typically act?

    <p>By binding to plasma membrane receptors and using second messengers</p> Signup and view all the answers

    What is the role of target cells in the endocrine system?

    <p>To respond to specific hormones that bind to their receptors</p> Signup and view all the answers

    What type of stimuli can trigger hormone release?

    <p>Humoral, neural, and hormonal stimuli</p> Signup and view all the answers

    Which of the following statements about autocrine and paracrine signaling is true?

    <p>Autocrine affects the secreting cell, while paracrine affects nearby cells</p> Signup and view all the answers

    Which of the following is NOT a major endocrine gland?

    <p>Sweat gland</p> Signup and view all the answers

    How do hormones exert their effects on target cells?

    <p>By altering cell activities through receptor binding</p> Signup and view all the answers

    Which statement accurately compares lipid-soluble and water-soluble hormones regarding their duration of action?

    <p>Lipid-soluble hormones have a longer half-life and sustained action</p> Signup and view all the answers

    Which of the following substances is an example of a hormone produced by the pancreas that has both endocrine and exocrine functions?

    <p>Glucagon</p> Signup and view all the answers

    What distinguishes exocrine glands from endocrine glands?

    <p>Exocrine glands secrete products via ducts to body surfaces or cavities</p> Signup and view all the answers

    Which hormone's mechanism of action involves activating intracellular receptors?

    <p>Thyroid hormone</p> Signup and view all the answers

    Study Notes

    Endocrine System Overview

    • The endocrine system works with the nervous system to coordinate and regulate body cell activity.
    • It influences metabolic activities through hormones transported in the blood.
    • Endocrine responses are slower but longer-lasting than nervous system responses.

    Endocrine vs. Exocrine Glands

    • Exocrine glands secrete products via ducts to membrane surfaces or body cavities. Examples are sweat, mucus, saliva, milk.
    • Endocrine glands (ductless) secrete hormones directly into surrounding tissue.

    Hormone Types and Actions

    • Hormones are long-distance chemical signals, traveling in blood or lymph.
    • Autocrines affect the same cells that secrete them.
    • Paracrines affect nearby cells.
    • Endocrines affect distant cells.

    Major Endocrine Glands

    • Pituitary
    • Thyroid
    • Parathyroid
    • Adrenal
    • Pineal
    • Hypothalamus
    • Pancreas
    • Gonads (ovaries/testes)
    • Other tissues (e.g., adipose cells, thymus, certain cells in the walls of the small intestine and other organs)

    Hormone Classification

    • Amino acid-based hormones: Most common, water-soluble, cannot cross the plasma membrane. Include amino acid derivatives, peptides, and proteins,.
    • Steroid hormones: Synthesized from cholesterol, lipid-soluble, can cross the plasma membrane. Include steroid, eicosanoid (classified as paracrine by some).

    Hormone Action

    • Target cells must have specific receptors for a hormone to take effect.
    • Factors affecting target cell activation include blood hormone levels, relative number of receptors on/in target cells, and receptor-hormone binding affinity.
    • Hormone action can alter target cell membrane permeability or alter protein synthesis. Hormone actions may involve activating or deactivating enzymes, or inducing secretory activity.
    • Water-soluble hormones usually act through second messenger systems.
    • Lipid-soluble hormones can directly activate genes.

    Hormone Release

    • Hormone levels are controlled by negative feedback systems.
    • Endocrine glands are stimulated by humoral stimuli, neural stimuli, or hormonal stimuli.

    Mechanisms of Hormone Release

    • Humoral stimuli: Changing blood levels of ions or nutrients directly stimulate the release of hormones.
    • Neural stimuli: Nerve fibers stimulate hormone release.
    • Hormonal stimuli: Hormones stimulate other endocrine organs to release their hormones

    Hormone Interactions

    • Multiple hormones can act on a target cell at the same time.
    • Permissiveness: One hormone cannot exert its effects without another hormone being present.
    • Synergism: Multiple hormones have an amplified effect on the target cell.
    • Antagonism: One hormone opposes the action of another.

    Nervous System Modulation

    • The nervous system can adjust hormone levels.
    • It can modify the stimulation or inhibition of endocrine glands.
    • The nervous system can override normal endocrine controls under extreme stress.

    Other Important Concepts

    • Cyclic AMP (cAMP) signaling: A critical second messenger system for water-soluble hormones.
    • Hormone half-life, onset, and duration: The time for hormone inactivation and removal from the body affects the duration of response.
    • Up-regulation and Down-regulation: Target cells can adjust receptor numbers in response to sustained high or low hormone levels.

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    Related Documents

    Lec 6a - Endocrine System Introduction - Nurs1230 PDF

    Description

    Explore the roles and functions of the endocrine system in regulating body activities through hormones. Understand the differences between endocrine and exocrine glands, as well as the various types of hormones and their actions. Learn about major endocrine glands and their contributions to overall health.

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