Introduction to Endocrine System
19 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 NOT a characteristic of the endocrine system?

  • It provides rapid and short-term control over body functions. (correct)
  • It utilizes chemical messengers called hormones.
  • It targets specific cells through the bloodstream.
  • It plays a key role in maintaining homeostasis.

    • Hormones can directly influence the rate of protein synthesis by altering the speed of transcription or translation.

    True (A)

    What are the two main types of cellular processes that hormones primarily affect?

    Transcription and translation

    Hormones that are lipid-soluble are also known as ______ hormones.

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

    Match the following hormone types with their chemical structure:

    <p>Amino acid derivatives = Small molecules derived from amino acids Peptide hormones = Larger molecules composed of amino acids Steroid hormones = Derived from lipids Eicosanoids = Larger, bulkier lipids</p> Signup and view all the answers

    Which of these is NOT a key example of a second messenger involved in hormonal signaling?

    <p>Sodium ions (Na+) (A)</p> Signup and view all the answers

    The posterior pituitary gland secretes hormones that are produced in the hypothalamus.

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

    What is the name of the direct capillary connection between the hypothalamus and the anterior pituitary?

    <p>Hypophyseal portal system</p> Signup and view all the answers

    The primary mechanism for regulating hormone secretion is called ______ feedback control.

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

    Match the anterior pituitary hormone with its primary function:

    <p>Thyroid Stimulating Hormone (TSH) = Stimulates the thyroid gland to produce thyroid hormones Adrenocorticotropic Hormone (ACTH) = Stimulates the adrenal cortex to produce cortisol and aldosterone Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH) = Stimulate the ovaries and testes Growth Hormone (GH) = Stimulates growth of skeletal muscle and bone Prolactin = Stimulates mammary glands to produce milk</p> Signup and view all the answers

    Which of these is NOT a releasing hormone secreted by the hypothalamus?

    <p>Prolactin-inhibiting hormone (D)</p> Signup and view all the answers

    Oxytocin promotes milk ejection from the mammary glands and is associated with feelings of bonding and social attachment.

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

    What are the two main hormones secreted by the adrenal medulla?

    <p>Epinephrine (adrenaline) and norepinephrine (noradrenaline)</p> Signup and view all the answers

    The outermost layer of the adrenal cortex is called the ______, which secretes mineralocorticoids.

    <p>zona glomerulosa</p> Signup and view all the answers

    Which hormone is responsible for increasing calcium levels in the blood?

    <p>Parathyroid hormone (PTH) (D)</p> Signup and view all the answers

    Cortisol, the main glucocorticoid, is known as a stress hormone because it increases blood glucose levels, provides resistance to stress, and has anti-inflammatory effects.

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

    What is the name of the zone in the adrenal cortex that secretes androgens?

    <p>Zona reticularis</p> Signup and view all the answers

    The thyroid gland is composed of follicles filled with ______ where thyroid hormones are stored.

    <p>follicular cavities</p> Signup and view all the answers

    Match the following hormones with their primary function:

    <p>Calcitonin = Lowers calcium levels in the blood Aldosterone = Promotes sodium reabsorption and potassium excretion Cortisol = Increases blood glucose levels, provides resistance to stress, and has anti-inflammatory effects Epinephrine = Associated with the &quot;fight or flight&quot; response</p> Signup and view all the answers

    Flashcards

    Endocrine System

    A system that uses hormones for long-term body control and homeostasis.

    Hormones

    Chemical messengers released by tissues, traveling through blood to target cells.

    Protein Synthesis

    The process involving transcription and translation to produce proteins.

    Amino Acid Derivatives

    Small hormone molecules derived from amino acids.

    Signup and view all the flashcards

    Lipid-Soluble Hormones

    Hormones that can easily pass through cell membranes and have internal receptors.

    Signup and view all the flashcards

    Water-Soluble Hormones

    Hormones that cannot pass through cell membranes and bind to surface receptors.

    Signup and view all the flashcards

    Carrier Proteins

    Proteins that transport lipid-derived hormones in the bloodstream.

    Signup and view all the flashcards

    Second Messengers

    Molecules that mediate effects of water-soluble hormones within cells.

    Signup and view all the flashcards

    Cyclic AMP (cAMP)

    A second messenger involved in signal transduction in cells.

    Signup and view all the flashcards

    Hypothalamus

    Brain region that regulates the endocrine system and hormone release.

    Signup and view all the flashcards

    Pituitary Gland

    Major endocrine gland, also called hypophysis, secretes hormones.

    Signup and view all the flashcards

    Anterior Lobe of Pituitary

    Secretes seven hormones including TSH, ACTH, and GH.

    Signup and view all the flashcards

    Oxytocin

    Hormone that stimulates contractions during labor and milk release.

    Signup and view all the flashcards

    Antidiuretic Hormone (ADH)

    Promotes water reabsorption in kidneys, controls thirst.

    Signup and view all the flashcards

    Humoral Stimuli

    Hormone release triggered by changes in blood composition.

    Signup and view all the flashcards

    Negative Feedback Control

    Mechanism where high hormone levels inhibit their own release.

    Signup and view all the flashcards

    Thyroid Hormones (T3/T4)

    Regulate metabolism, growth, and development in the body.

    Signup and view all the flashcards

    Parathyroid Hormone (PTH)

    Increases blood calcium levels by stimulating osteoclasts.

    Signup and view all the flashcards

    Mineralocorticoids

    Hormones that regulate mineral balance, mainly aldosterone.

    Signup and view all the flashcards

    Glucocorticoids

    Hormones that regulate glucose metabolism, stress response.

    Signup and view all the flashcards

    Adrenal Cortex

    Outer portion of adrenal glands; secretes essential hormones.

    Signup and view all the flashcards

    Adrenal Medulla

    Inner portion of adrenal gland; secretes epinephrine and norepinephrine.

    Signup and view all the flashcards

    Hypophyseal Portal System

    Direct blood vessel connection between hypothalamus and anterior pituitary.

    Signup and view all the flashcards

    Study Notes

    Introduction to Endocrine System

    • The endocrine system, alongside the nervous system, plays a crucial role in controlling homeostasis.
    • It uses hormones, chemical messengers transported through the blood, to target cells.
    • The endocrine system controls long-term processes, unlike the nervous system's rapid responses.

    Hormonal Action and Cellular Mechanisms

    • Protein synthesis, involving transcription (DNA to mRNA) and translation (mRNA to protein), is central to cellular activity.
    • Hormones influence cellular processes by:
      • Activating genes for enzyme synthesis (transcription).
      • Altering transcription/translation rates to adjust protein production.
      • Directly activating or inhibiting enzymes.

    Types and Properties of Hormones

    • Hormones are categorized by chemical structure:
      • Amino acid derivatives (small molecules).
      • Peptide hormones (large chains of amino acids).
      • Lipid derivatives:
        • Steroid hormones (small, lipid-based).
        • Eicosanoids (larger, lipid-based).
    • Hydrophobic hormones: Lipid-soluble, pass through cell membranes (e.g., thyroid hormones, steroid hormones).
    • Hydrophilic hormones: Water-soluble, do not easily pass cell membranes (e.g., peptide hormones, glycoproteins, adrenaline).

    The Role of Carrier Proteins

    • Lipid-derived, hydrophobic hormones require carrier proteins for transport in the bloodstream.
    • Carrier proteins maintain hormone concentration in the blood.
    • Examples of lipid-derived hormones bound by carrier proteins include estrogen and testosterone.

    Mechanism of Hormone Action

    • Hydrophobic hormones: Enter cells freely and have receptors inside the cell.
    • Hydrophilic hormones: Cannot enter cells, bind to receptors on the cell surface, triggering second messengers.

    Second Messengers

    • Second messengers mediate the effects of water-soluble hormones within cells.
    • Key examples include cyclic AMP (cAMP), cyclic GMP (cGMP), and calcium ions (Ca²⁺).

    Hormonal Control: Hypothalamus and Pituitary Gland

    • Hypothalamus: Regulates the endocrine system, part of the nervous system.
    • Pituitary Gland (Hypophysis): Major endocrine gland below the hypothalamus.
      • Secretes nine peptide hormones that use cAMP as a second messenger.
      • Three lobes:
        • Anterior Lobe (Adenohypophysis): Secretes seven hormones.
        • Posterior Lobe (Neurohypophysis): Releases oxytocin and antidiuretic hormone (ADH), produced in the hypothalamus.
        • Pars Intermedia: Secretes melanocyte-stimulating hormone (MSH).

    Hormone Secretion

    • Humoral stimuli: Changes in extracellular fluid composition trigger hormone release (e.g., calcium levels).
    • Hormonal stimuli: One hormone triggers the release of another.
    • Neural stimuli: Neurotransmitters at neuroglandular junctions stimulate hormone secretion (e.g., adrenaline).

    Hypophyseal Portal System

    • Connects hypothalamus and anterior pituitary with direct capillary network for rapid hormone delivery.

    Negative Feedback Control

    • Regulates hormone secretion.
    • High hormone levels inhibit further release of both hypothalamic releasing hormones and anterior pituitary stimulating hormones.
    • Low hormone levels stimulate their release.

    Anterior Pituitary Hormones

    • Secretes seven hormones:
      • TSH: Stimulates thyroid hormones (T3 and T4).
      • ACTH: Stimulates adrenal cortex hormones (cortisol, aldosterone).
      • FSH and LH: Gonadotropins, stimulate ovaries and testes.
      • GH: Stimulates skeletal muscle and bone growth.
      • Prolactin: Stimulates milk production.

    Hypothalamic Control of Anterior Pituitary

    • Releasing hormones stimulate anterior pituitary hormone release (e.g., TRH, CRH).
    • Inhibiting hormones inhibit anterior pituitary hormone release (e.g., somatostatin, PIH).

    Posterior Pituitary Hormones

    • Oxytocin: Stimulates uterine contractions, milk ejection, bonding.
    • Antidiuretic Hormone (ADH): Promotes water reabsorption in kidneys, raises blood pressure, stimulates thirst.

    Thyroid Gland

    • Located in the neck. Contains follicles with thyroid hormone storage.
    • Thyroid Hormones (T3 and T4): Regulate metabolism, growth, development, and the nervous system.
    • T4 (thyroxine): Four iodine atoms.
    • T3 (triiodothyronine): Three iodine atoms.
    • Calcitonin: Lowers blood calcium by reducing osteoclast activity and increasing calcium excretion.

    Parathyroid Glands

    • Four glands on the posterior thyroid.
    • Parathyroid Hormone (PTH): Increases blood calcium by stimulating osteoclasts, preventing urinary calcium loss, and promoting intestinal calcium absorption, opposing calcitonin.

    Adrenal Glands

    • Located above the kidneys.
      • Adrenal Cortex: Outer layer, three zones:
        • Zona glomerulosa: Secretes mineralocorticoids (e.g., aldosterone).
        • Zona fasciculata: Secretes glucocorticoids (e.g., cortisol).
        • Zona reticularis: Secretes androgens.
      • Adrenal Medulla: Inner layer, secretes epinephrine (adrenaline) and norepinephrine (noradrenaline).

    Adrenal Cortex Hormones

    • Mineralocorticoids: Regulate mineral balance (e.g., aldosterone).
    • Glucocorticoids: Regulate glucose metabolism (e.g., cortisol).
    • Androgens: Contribute to prepubescent growth and female hormone balance.

    Adrenal Medulla Hormones

    • Epinephrine (Adrenaline): Key "fight or flight" hormone.
    • Norepinephrine (Noradrenaline): Associated with stress response and aggression.

    Studying That Suits You

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

    Quiz Team

    Description

    Explore the essential functions and mechanisms of the endocrine system in this quiz. Understand how hormones control homeostasis, influence cellular activities, and the different types of hormones and their properties. Gain insights into the comparison between hormonal and nervous system controls.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser