Endocrine Physiology Flashcards
What is the difference between a tropic hormone & a non-tropic hormone?
-Tropic hormones regulate the production and secretion of another hormone
-Non-tropic hormone exerts its effects on non-endocrine target tissues
What are the general principles of endocrinology?
-Endocrine system relies on duration not speed
-Tropic hormone
-Non-tropic hormone
-Single endocrine gland may produce multiple hormones
-Single hormone may be secreted by more than one endocrine gland
-Single hormone may have more than one type of target cell and thus induce more than one type of effect
-Single target cell may be influenced by more than one hormone
-The same chemical messenger may be either a hormone or a neurotransmitter
-Some organs are exclusively endocrine in function, while other organs of the endocrine system perform non-endocrine functions in addition to secreting hormones
-Endocrine system provide a temporal coordination of function
How are peptide hormones transported?
-Transported dissolved in the plasma
How are peptide hormones stored?
-Stored in secretory vessels
How are peptide hormones released?
-Released through exocytosis into bloodstream mediated by specific stimuli
What is a pro-hormone?
Amine hormones are derived from what amino acid?
-Tyrosine
How are thyroid hormones transported?
-Transported bound to plasma proteins
How are catecholamines transported?
-Transported dissolved in the plasma
How are steroid hormones transported?
-Transported bound to plasma proteins
Are steroid hormones stored?
-Steroid hormones are not stored after their formation
-Only the cholesterol is stored
How is the rate of secretion of steroid hormones controlled?
-Rate of secretion is controlled entirely by rate of hormone synthesis
What is the difference in the targets for hydrophilic hormones vs lipophilic hormones?
-Hydrophilic hormones bind to specific receptors of the cell membrane
-Lipophilic hormones are able to cross the membrane and mind to receptors located within the cell membrane -
What are the 3 mechanisms by which hormones elicit their effects in their target cells?
-Hydrophilic hormones alter cells permeability by the conformational change of channel proteins
-Hydrophilic hormones activate second messenger systems within the target cell which alter intracellular proteins produce desired effect
-Lipophilic hormones function by activating specific genes in the target cell; induce the formation of new intracellular proteins
What are the 3 common actions of hormones?
-The actions of hormones are greatly amplified at the target cell
-Hormones regulate the rates of existing reactions instead of initiating new reactions
-Hormone action is relatively slow
What hormone is secreted by the pineal gland? What are the functions of this hormone?
-Secretes melatonin (hormone of darkness)
-Functions: regulates biological clock, induces natural sleep, inhibits reproductive activity, shuts down ovulation, slow aging via the removal of free radicals, enhance immunity
What hormones are secreted by the anterior pituitary gland? What are their functions?
-Growth hormone: regulating overall body growth
-Thyroid stimulating hormone (TSH): Stimulates thyroid hormone secretion; growth of thyroid gland
-Adrenocorticotropic hormone (ACTH): Stimulates cortisol secretion by adrenal cortes; growth of adrenal cortex
-Follicle stimulating hormone (FSH): Stimulates gamete production
-Luteinizing hormone (LH): Stimulate ovulation; secretion of estrogen and progesterone in females; testosterone in males;
-Prolactin: Enhances breast development and milk production
What hormones are secreted by the hypothalamus? What are their functions?
-Thyrotropin releasing hormone: TSH and prolactin
-Corticotropin releasing hormone: ATCH
-Gonadotropin releasing hormone: FSH and LH
-Growth hormone releasing hormone: GH
-Prolactin releasing factor: Prolactin
-Prolactin inhibiting hormone: Prolactin
What hormones are secreted by the posterior pituitary? Where were these hormones produced (be specific)?
-Oxytocin: Increases uterine contractility; stimulates milk ejection
-Vasopressin: Increases H2) permeability in kidneys collecting tubules; induces arteriolar vasoconstriction
What are the functions of the thyroid gland?
-Increases basal metabolic rate
-Calorigenic (heat) effect
-Promote synthesis and degradation of carbohydrates, proteins, and fat
-Sympathomimetic effect by increasing cell responsiveness to catecholamines via increasing receptor density
-Facilitates cardiovascular output
-Facilitates the effects of growth hormone
-Necessary for proper growth and functioning of the nervous system
What is calcitonin & what cells secrete it?
-C cells are located between follicles and secrete calcitonin for proper calcium metabolism
What are T3 & T4?
-Regulate own release at the level of the anterior pituitary (inhibit TSH release)
What are the 3 layers of the adrenal glands cortex? What hormones are produced by them?
-Zona glomerulosa: aldosterone production
-Zona fasciculata: cortisol production, sex hormone production
-Zona reticularis: cortisol production, sex hormone production
What hormone classes are secreted by the adrenal glands?
-Mineralocorticoids: mineral balance
-Glucocorticoids: energy metabolism
-Sex hormones
