Biology Chapter 45 Flashcards
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Questions and Answers

Which type of hormone is lipid soluble?

  • Insulin
  • Cortisol
  • Estrogen
  • Steroids (correct)

    • Which molecules determine the tissue specificity of hormones?

    Receptors

    Lipid-insoluble hormones affect their target cells by binding to receptors inside the cell.

    False

    Which of the following statements about lipid-soluble hormones is true?

    <p>They act by affecting the transcription of genes.</p> Signup and view all the answers

    Which of the following is a structure that allows hormone-receptor complexes to bind to specific DNA sequences?

    <p>Zinc finger</p> Signup and view all the answers

    What is the role of cAMP in the signal transduction pathway activated by epinephrine?

    <p>It binds to and activates protein kinase A.</p> Signup and view all the answers

    For a signal transduction pathway to be activated, hormones must be present in the bloodstream at very high concentrations.

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

    Receptors for nonsteroid hormones are located in _____

    <p>association with a cell's plasma membrane</p> Signup and view all the answers

    Which of these is a nonsteroid hormone?

    <p>Epinephrine and oxytocin</p> Signup and view all the answers

    How do nonsteroid hormones differ from steroid hormones?

    <p>Nonsteroid hormones act via signal transduction pathways.</p> Signup and view all the answers

    Which of these extracellular signal molecules could diffuse through a plasma membrane and bind to an intracellular receptor?

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

    The primary reason steroid hormones usually act slowly is that _____

    <p>they turn genes on or off.</p> Signup and view all the answers

    Steroid hormone-receptor complexes act in _____

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

    The hormone epinephrine causes opposite effects in two populations of target cells because _____

    <p>each set of target cells has different receptor-transduction mechanisms.</p> Signup and view all the answers

    Among insects, the metamorphic transition from pupal form to adult form is associated with _____

    <p>high levels of ecdysteroids and reduced levels of juvenile hormone.</p> Signup and view all the answers

    In their mechanism of action, a difference between lipid-soluble and water-soluble hormones is that _____

    <p>lipid-soluble hormones bind to an intracellular receptor.</p> Signup and view all the answers

    Oxytocin secretion and milk release from the mammary glands of lactating female mammals are initiated by _____

    <p>the physical sensation of the baby sucking at the nipple.</p> Signup and view all the answers

    The counter-regulatory functions of the pancreas refer to the fact that it _____

    <p>releases one hormone that reduces glucose levels and another that increases them.</p> Signup and view all the answers

    This disorder typically arises prior to puberty and is generally treated by injections of the hormone missing from the affected individual's bloodstream.

    <p>Type I diabetes mellitus</p> Signup and view all the answers

    What is the function of endocrine glands?

    <p>They release hormones into the bloodstream.</p> Signup and view all the answers

    The homeostatic system for blood calcium concentration is maintained by the hormones calcitonin and parathyroid hormone.

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

    Which of the following statements about the pituitary gland is false? Neurosecretory cells produce hormones that are stored in the anterior pituitary.

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

    The pancreas is responsible for producing hormones that maintain the homeostatic levels of glucose in the blood.

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

    How is the production of hormones such as thyroxine and estrogen regulated?

    <p>The hypothalamus directs the anterior pituitary to produce hormones.</p> Signup and view all the answers

    What is true about endocrine glands and the hormones they produce?

    <p>Aldosterone produced by the adrenal glands controls the reabsorption of sodium ions by the kidneys.</p> Signup and view all the answers

    Gigantism, a condition characterized by exceptionally rapid growth, is sometimes caused by a tumor that induces the gland in which it develops to overproduce a certain hormone. Where would such a tumor be expected to grow?

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

    Which of these glands secretes releasing hormones?

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

    Which of these hormones are responsible for the 'fight or flight' response to danger?

    <p>Epinephrine and norepinephrine</p> Signup and view all the answers

    Adrenocorticotropic hormone (ACTH) triggers the release of _____ in response to stress.

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

    _____ are the main male hormones.

    <p>Androgens (testosterone)</p> Signup and view all the answers

    What hormone promotes water retention by the kidneys?

    <p>Antidiuretic hormone (ADH)</p> Signup and view all the answers

    Which hormone opposes the action of parathyroid hormone?

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

    Which hormone stimulates hormone production by the ovaries and testes?

    <p>Luteinizing hormone (LH)</p> Signup and view all the answers

    Which hormone stimulates milk production?

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

    Steroid and peptide hormones typically have in common?

    <p>Their requirement for travel through the bloodstream.</p> Signup and view all the answers

    Shortly after ingesting a big plate of carbohydrate-rich pasta, what results would you expect in blood hormone levels?

    <p>High insulin, low glucagon</p> Signup and view all the answers

    Study Notes

    Hormones and Their Characteristics

    • Steroids are lipid-soluble hormones that can easily cross cell membranes.
    • Tissue specificity of hormones is determined by receptors found in target tissues.
    • Lipid-insoluble hormones bind to receptors on the cell surface and utilize signal transduction pathways, while lipid-soluble hormones influence gene transcription directly.
    • Zinc fingers are DNA-binding domains on some hormone receptors, allowing hormone-receptor complexes to bind to specific DNA sequences.

    Mechanisms of Action

    • Cyclic AMP (cAMP) activates protein kinase A, which phosphorylates enzymes in the signal transduction pathway, playing a crucial role in hormonal responses.
    • Hormones can activate pathways effectively at low concentrations, amplifying their effects through second messengers.
    • Nonsteroid hormones act via signal transduction mechanisms, whereas steroid hormones directly affect transcription in the nucleus.
    • Estrogen can diffuse through a plasma membrane to bind with an intracellular receptor, unlike most nonsteroid hormones.

    Physiological Effects of Hormones

    • Steroid hormones take longer to exert effects due to changes in gene expression requiring time to manifest.
    • Oxytocin release during breastfeeding is triggered by the baby's sucking, demonstrating a neuroendocrine pathway.
    • The pancreas releases insulin and glucagon to maintain glucose levels, exhibiting counter-regulatory functions.

    Endocrine System and Homeostasis

    • Endocrine glands release hormones into circulation, influencing processes like glucose regulation and calcium homeostasis (calcitonin and parathyroid hormone).
    • The pituitary gland, particularly its anterior portion, produces various hormones; neurosecretory cells work in the posterior pituitary.
    • Hormone production, such as that of thyroxine and estrogen, is regulated by the hypothalamus through the anterior pituitary gland.
    • The adrenal cortex releases glucocorticoids in response to ACTH during stress.

    Hormonal Disorders and Regulation

    • Type I diabetes mellitus results from inadequate insulin secretion due to pancreatic dysfunction, often treated with insulin injections.
    • Gigantism is linked to tumors in the pituitary gland causing excessive growth hormone production.
    • Releasing hormones are secreted by the hypothalamus, playing a vital role in regulating the endocrine system.

    Key Hormones and Their Functions

    • Antidiuretic hormone (ADH) promotes kidney water retention.
    • Calcitonin opposes parathyroid hormone, lowering blood calcium levels.
    • Luteinizing hormone (LH) stimulates hormone production in the ovaries and testes.
    • Prolactin encourages milk production in lactating mammals.

    Hormonal Responses and Effects

    • Following carbohydrate-rich meals, insulin levels increase while glucagon levels decrease, facilitating glucose uptake.
    • Epinephrine and norepinephrine are critical for activating the "fight or flight" response, eliciting various physiological changes.
    • Hormonal responses vary in target cells based on specific receptor-transduction mechanisms, exemplified by the differing effects of epinephrine on vasodilation and vasoconstriction.

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    Test your knowledge of hormones and their mechanisms with these flashcards from Biology Chapter 45. Explore lipid-soluble and lipid-insoluble hormones, as well as the role of receptors in hormone action. Perfect for quick revisions or study sessions!

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