Endocrinology Flashcards
What is an endocrine gland?
Does not have a duct system.
What is an exocrine gland?
Has a duct system.
What is GnRH?
Gonadotropin-releasing hormone.
What is the source of GnRH?
Hypothalamus.
What is the major action of GnRH?
Increases secretions of FSH and LH.
What is CRH?
Corticotropin-releasing hormone.
What is the source of CRH?
Hypothalamus.
What is the major action of CRH?
Increases secretion of ACTH.
What is TRH?
Thyrotropin-releasing hormone.
What is the source of TRH?
Hypothalamus.
What is the major function of TRH?
Increases the secretion of TSH.
What is PIH?
Prolactin inhibiting hormone (dopamine)
What is the source of PIH?
Hypothalamus.
What is the major function of PIH?
Decreases secretion of PRL.
What is GHRH?
Growth hormone-releasing hormone.
What is the source of GHRH?
Hypothalamus.
What is the major function of GHRH?
Increases the secretion of GH.
What is SS?
Somatostatin.
What is the source of SS?
Hypothalamus.
What is the major function of SS?
Decreases the secretion of GH.
What hormones are secreted from the hypothalamus?
GnRH CRH TRH PIL GHRH SS
What is FSH?
Follicle-stimulating hormone
What is the source of FSH?
Anterior pituitary
What is the main action of FSH?
Stimulates follicle growth.
What is LH?
Luteinizing hormone.
What is the source of LH?
Anterior pituitary.
What is the main function of LH?
Causes ovulation, increases testosterone secretion.
What is ACTH?
Adrenocorticotropic hormone.
What is the source of ACTH?
Anterior pituitary.
What is the main function of ACTH?
Increases secretion of adrenal glucocorticosteroids.
What is TSH?
Thyroid stimulating hormone
What is the source of TSH?
Anterior pituitary
What is the main function of TSH?
Increase secretion of thyroid hormones T3/T4
What is PRL?
Prolactin
What is the source of PRL?
Anterior pituitary
What is the main function of PRL?
Increases production of milk
What is GH?
Growth hormone
What is the source of GH?
Anterior pituitary
What is the main function of GH?
Increases protein synthesis and increases growth.
What hormones are secreted by the anterior pituitary?
FSH LH ACTH TSH PRL GH
What is OXY?
Oxytocin
What is the source of OXY?
Posterior pituitary
What is the main function of OXY?
Expulsion of milk, contraction of uterus.
What is ADH?
Antidiuretic hormone (vasopressin)
What is the source of ADH?
Posterior pituitary
What is the main function of ADH?
Increases water reabsorption and decreases urine volume.
What hormones are secreted by the posterior pituitary?
Oxytocin and ADH.
What are the three forms of hormones?
- Protein (peptides, polypeptides, glycoproteins)
- Lipids (steroids, eicosanoids)
- Monoamines (catecholamines, thyroid hormones)
How are steroid hormones synthesized?
- Cholesterol
- Pregnenolone
- Progesterone (testosterone to estrogen)
- Aldosterone (or cortisol)
What is the mechanism of endocrine cells?
Release hormones from hormone producing cells into a vessel, which carries hormones to the target cell.
What is the mechanism of neuroendocrine cells?
Neurons release hormones or transmitters into blood stream, carried to target cell.
What is the mechanism of paracrine cells?
Hormone producing cells secrete hormones that diffuse hormones through ECF to nearby cells (local)
What is the mechanism of autocrine cells?
Hormone producing cell and target cell are the same.
What hormones bind to cell surface receptors?
Catecholamines and protein hormones.
What hormones bind to intracellular receptors?
Steroid hormones and thyroid hormones.
What are the two forms of cell surface receptors?
G-protein linked receptors, catalytic (tyrosine kinase) receptors.
What hormones act on G-protein coupled receptors?
Adrenaline, glucagon, FSH, LHM TSH, PTH
What hormones act on catalytic receptors?
Insulin and GH.
What is the solubility of protein (and catecholamine) hromones?
Water-soluble
What is the solubility of steroid hormones?
Lipid soluble.
What are protein steroid synthesized from?
Amino acids.
What are steroid hormones synthesized from?
Cholesterol
How are protein hormones stored?
In vesicles or by exocytosis.
How are steroid hormones stored?
Not stored, secreted by diffusion.
How are protein hormones transported?
Do not need special transport through blood.
How are steroid hormones transported?
Bound to plasma proteins in the blood
What is the time course of action for protein hormones?
Fast
What is the time course of action for steroid hormones?
Slow.
Describe the morphology of the pituitary:
Extends off the hypothalamus and upward from the mouth, contains two glands (anterior and pituitary) as well as a pituitary stalk and median eminence that divides the glands.
Where did the anterior pituitary stem from?
Mouth region.
Where did the posterior pituitary stem from?
Brain.
How does hormone communication occur in the anterior pituitary?
Neurodendocrine cells in the hypothalaus extend to the median eminence where they synapse on the primary plexus. Secreted hormones travel down through portal blood vessels into the anterior pituitary where they form the secondary plexus. Hormones close to the secondary plexus can be acted on by hormones that diffuse out of blood stream.