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Endocrine System - Anatomy & Physiology

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Terms in this set (30)

  • Primary function of the endocrine system
    Releases chemical messengers called hormones into the bloodstream to regulate metabolic activities and maintain homeostasis.
  • Difference between endocrine and nervous systems
    The nervous system uses fast electrochemical impulses for rapid responses; the endocrine system uses hormones for slower, prolonged metabolic regulation.
  • Difference between endocrine and exocrine glands
    Endocrine glands are ductless and release hormones into blood; exocrine glands have ducts and secrete non-hormonal products to surfaces.
  • Two chemical classes of hormones
    Amino acid-based hormones (most hormones, act via second messengers) and steroid hormones (from cholesterol, act via direct gene activation).
  • Mechanism of action for amino acid-based hormones
    Bind to cell membrane receptors and activate intracellular second messengers like cyclic AMP to alter cell function.
  • Mechanism of action for steroid hormones
    Diffuse into cells, bind nuclear receptors, and activate gene transcription to produce specific proteins.
  • Factors affecting target cell activation by hormones
    Blood hormone levels, number of receptors on target cells, and affinity between hormone and receptor.
  • Types of cellular changes induced by hormones
    Changes in membrane permeability, protein synthesis, enzyme activity, secretory activity, and stimulation of mitosis.
  • Five broad effects of hormones on the body
    Regulate internal environment, respond to stress, integrate growth and development, support reproduction, and regulate metabolism and energy balance.
  • Three types of stimuli that trigger hormone secretion
    Hormonal (hormones stimulate other glands), humoral (changes in blood ions/nutrients), and neural (nerve fibers stimulate hormone release).
  • Role of the hypothalamus in endocrine control
    Controls pituitary gland by producing releasing and inhibiting hormones for anterior pituitary and directly releasing posterior pituitary hormones via neurons.
  • Hormones released by the posterior pituitary
    Oxytocin (uterine contractions) and antidiuretic hormone (ADH) (water reabsorption in kidneys).
  • Six hormones secreted by the anterior pituitary
    TSH, ACTH, FSH, LH (regulate other glands), plus growth hormone (GH) and prolactin (PRL) affecting non-endocrine targets.
  • Function of thyroid hormone
    Major metabolic hormone that increases basal metabolic rate, heat production, and tissue growth; includes T4 and active T3.
  • Function of calcitonin
    Lowers blood calcium by stimulating calcium uptake into bone; produced by thyroid parafollicular cells.
  • Role of parathyroid hormone (PTH)
    Increases blood calcium by stimulating bone resorption, kidney reabsorption, and intestinal absorption of calcium.
  • Hormones produced by the adrenal cortex layers
    Zona glomerulosa: mineralocorticoids (e.g., aldosterone); zona fasciculata: glucocorticoids (e.g., cortisol); zona reticularis: gonadocorticoids (androgens).
  • Function of aldosterone
    Regulates sodium and potassium balance by promoting sodium reabsorption and potassium excretion in kidneys, increasing blood volume.
  • Role of glucocorticoids
    Help maintain blood sugar, resist stress, and regulate metabolism; cortisol is a key glucocorticoid.
  • Hormones secreted by the adrenal medulla
    Catecholamines epinephrine and norepinephrine, which mediate short-term stress responses like increased heart rate and blood sugar.
  • Function of insulin
    Lowers blood glucose by promoting cellular glucose uptake, glycogen formation, and glucose breakdown for ATP.
  • Function of glucagon
    Raises blood glucose by stimulating glycogen breakdown and gluconeogenesis in the liver.
  • Hormones produced by the gonads
    Ovaries produce estrogen and progesterone; testes produce testosterone; all are steroid hormones regulating reproduction and secondary sex characteristics.
  • Role of the thymus gland
    Produces thymosin, which is important for T lymphocyte development and immune response.
  • Cause and effect of gigantism
    Hypersecretion of growth hormone in children causes excessive height with normal body proportions.
  • Cause and effect of acromegaly
    Hypersecretion of growth hormone after epiphyseal plate closure causes enlargement of hands, feet, and face.
  • Cause and effect of diabetes insipidus
    ADH deficiency leading to excessive urine output and intense thirst.
  • Cause and symptoms of Graves' disease
    Autoimmune hyperthyroidism causing elevated metabolic rate, sweating, rapid heartbeat, and weight loss.
  • Cause and symptoms of Addison's disease
    Deficiency of glucocorticoids and mineralocorticoids causing weight loss, low blood sugar, dehydration, and low blood pressure.
  • Cause and symptoms of diabetes mellitus
    Hyposecretion or hypoactivity of insulin causing high blood glucose, excessive urination, thirst, and hunger.