Endocrinology Flashcards
Hormone → blood circulation → specific receptor
Endocrine
Hormone → interstitial space → adjacent cell
Paracrine
Hormone → self-regulation
Autocrine
Hormone → direct cell-to-cell contact
Juxtacrine
Hormone → gut
Exocrine
Hormone → neurons → extracellular space
Neurocrine
Hormone → neurons → nerve endings
Neuroendocrine
Glycoproteins
FSH, hCG, TSH, LH
Polypeptides
ACTH, ADH, GH, angiotensin, calcitonin, CCK, gastrin, glucagons, insulin, MSH, oxytocin, PTH, PRL, somatostatin
Steroids Precursor:
cholesterol
Steroids
Aldosterone, cortisol, estrogen, progesterone, testosterone, vitamin D
Derived from amino acids
Amines
Catecholamines, T3, T4
Amines
Connected to the posterior pituitary by the infundibulum stalk
Hypothalamus
Hypophyseal hormones:
TRH, GnRH, GH-IH, GH-RH, PIF
Melatonin: decreases pigmentation of the skin
Pineal gland
Master Gland ; Located in the sella turcica or Turkish saddle
Pituitary gland
True endocrine gland
Anterior Pituitary (Adenohypophysis)
Hormones: PRL, GH, FSH, LH, TSH, MSH, ACTH
Anterior Pituitary (Adenohypophysis)
GH (Somatotropin) Most abundant of all pituitary hormones Structurally similar to PRL and HPL Markedly elevated during deep sleep Dwarfism Decreased GH Acromegaly Increased GH GH deficiency tests 1. Insulin tolerance test = Gold standard (Confirmatory test) 2. Arginine stimulation test = 2nd confirmatory test Tests for Acromegaly 1. Somatomedin C or insulin-like growth factor I (Screening) -Increased: Acromegaly -Decreased: GH deficiency 2. OGTT (Confirmatory) -75g glucose FSH Spermatogenesis LH Helps Leydig cells to produce testosterone (male) Ovulation (female) Synthesis of androgens, estrogens, and progesterone TSH (Thyrotropin) Stimulates thyroid gland to produce T3 and T4 Increased: 1’ hypothyroidism, 2’ hyperthyroidism Decreased: 1’ hyperthyroidism, 2’ hypothyroidism, 3’ hypothyroidism ACTH (Corticotropin) Highest: 6-8 AM Lowest: 6-11 PM Not allowed to have contact with glass because it adheres to glass surface Collect blood in plastic tubes Prolactin Initiation and maintenance of lactation Inhibited by Dopamine Highest: 4AM and 8AM, and 8PM and 10PM Increased: Menstrual irregularity, infertility, amenorrhea, galactorrhea Panhypopituitarism From pituitary tumor (adenoma) or Ischemia Pituitary ischemia (Shechan’s) Hemorrhage or shock in a pregnant female at the time of deliver Posterior pituitary (Neurohypophysis) Release but not produce oxytocin and vasopressin Oxytocin Uterine contraction and milk ejection ADH/AVP (Arginine vasopressin) H2O reabsorption (DCT and CD) Stimulus: Increased plasma osmolality (>295 mOsm/kg), decreased blood vol. Promotes factor VII and vWF release Overnight water deprivation test (Conc. test) Diagnostic test for ADH Neurogenic DI True Diabetes Insipidus Failure of the pituitary gland to secrete ADH Nephrogenic DI Failure of the kidneys to respond to normal or elevated ADH SIADH Syndrome of inappropriate ADH Sustained production of ADH Decreased urine volume Low plasma osmolality Low serum electrolytes Thyroid Gland Butterfly-shaped 2 lobes = connected by the isthmus Follicle Fundamental structural unit of the thyroid gland Follicular cells Secrete T3 and T4 Parafollicular or C cells Secrete calcitonin
