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Anatomy & Physiology: Endocrine System Hormones and Mechanisms

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Termini in questo insieme (19)

  • Four criteria that make a chemical signal a hormone

    1. Secreted by endocrine cells into the blood.
    2. Transported to distant target cells.
    3. Acts at low concentrations.
    4. Binds to specific receptors to trigger a response.

  • Cellular mechanism of action of a hormone

    Hormones bind to specific receptors on or in target cells, triggering intracellular signaling pathways that alter cell function or gene expression.

  • Three chemical classes of hormones with examples

    Peptide: Insulin
    Steroid: Cortisol
    Amine: Epinephrine

  • Synthesis, storage, and release: peptide vs steroid hormones

    Peptide hormones are synthesized as preprohormones, stored in vesicles, and released by exocytosis.
    Steroid hormones are synthesized on demand from cholesterol and diffuse out of cells without storage.

  • Location of hormone receptors: peptide vs steroid hormones

    Peptide hormone receptors are on the cell surface membrane.
    Steroid hormone receptors are intracellular, in the cytoplasm or nucleus.

  • Cellular mechanisms of action: peptide vs steroid hormones

    Peptide hormones activate second messenger systems.
    Steroid hormones directly modulate gene transcription.

  • Three main groups of amine hormones

    Catecholamines: Epinephrine, norepinephrine
    Thyroid hormones: T3, T4
    Others: Dopamine

  • Role of the nervous system in endocrine reflexes

    The nervous system detects stimuli and triggers endocrine responses by stimulating hormone release, integrating rapid control with hormonal regulation.

  • Structure and function of the anterior pituitary

    The anterior pituitary is glandular tissue that synthesizes and secretes six hormones regulated by hypothalamic releasing and inhibiting hormones.

  • Structure and function of the posterior pituitary

    The posterior pituitary is neural tissue that stores and releases hormones made in the hypothalamus, such as oxytocin and vasopressin.

  • Six anterior pituitary hormones and their primary targets

    GH: Growth effects on tissues
    TSH: Thyroid gland
    ACTH: Adrenal cortex
    FSH: Gonads
    LH: Gonads
    Prolactin: Mammary glands

  • Hormones controlling anterior pituitary hormone release

    Hypothalamic releasing and inhibiting hormones regulate anterior pituitary secretion, e.g., TRH stimulates TSH release, somatostatin inhibits GH release.

  • Long-loop negative feedback in anterior pituitary hormones

    Hormones from peripheral glands inhibit both the anterior pituitary and hypothalamus to regulate hormone levels, e.g., cortisol inhibits ACTH and CRH.

  • Negative feedback loops for insulin and parathyroid hormone

    Insulin secretion is regulated by blood glucose levels (negative feedback). Parathyroid hormone secretion is regulated by blood calcium levels via negative feedback.

  • Permissiveness in hormone interactions

    One hormone enhances the target organ's response to a second hormone, e.g., thyroid hormone increases the effect of epinephrine on fat breakdown.

  • Synergism in hormone interactions

    Two hormones produce a greater combined effect than the sum of their separate effects, e.g., glucagon and epinephrine both increase blood glucose.

  • Functional antagonism in hormone interactions

    One hormone opposes the action of another, e.g., insulin lowers blood glucose while glucagon raises it.

  • Three most common types of endocrine pathologies

    Hypersecretion: Excess hormone production
    Hyposecretion: Deficient hormone production
    Abnormal responsiveness: Target tissue resistance

  • Using negative feedback to locate endocrine problems

    By analyzing hormone levels and feedback patterns, one can identify if a problem lies in the hypothalamus, pituitary, or peripheral gland in multi-gland pathways.