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SIUE Endocrine
Endocrine
Question | Answer |
---|---|
Exocrine Gland | Has a duct, secretes outside the skin or into a lumen |
Describe an Endodcrine Gland | Ductless; secretes products directly into the blood |
Describe local hormones | Hormones that act locally without first entering the blood; Paracrine, Autocrine, Juxtacrine |
Paracrine | Acts on an adjacent cell |
Autocrine | Has an effect on secreting cells |
Juxtacrine | has an effect on adjacent cells through direct contact |
What are the Tyrosine Derivative Hormones | TH and Catecolamines |
What are the cholesterol derivative hormones? | Steroids |
Examples of Steroid hormones | Estrogen, Progesterone,estradiol, cortisol, Testosterone, Aldosterone, |
What type of receptors do steroids bind to? | Intracellular (slow) |
What are the protein/peptide hormones? | GH, Prolactin, ACTH, FSH, LH, TSH, ADH, Oxytocin, Insulin, Glucagon |
Whay type of receptors do Protein/Peptide bind to? | Cell Membrane (FAST) |
What are the Eicosanoid Hormones? | Prostaglandins |
How do Prostaglandins form? | Lipids are cleaved by phospholipase A2 into arachodonic acid, which is a precursor to prostaglandins |
Glucocorticoids Effect on Prostaglandin formation | They inhibit the action of phospholipase A2, so the AA cannot be formed |
What transforms AA to prostaglandins? | Cyclooxygenase |
COX I and II inhibators | Block AA from becoming prostaglandin. (ex. ASA and NSAID) |
Describe Membrane receptors | Water Soluble protiens on the cell membrane (cAMP); They are fast |
Describe Intracellular Receptors | Lipid soluble hormones connect with these; slow process due to transcription that takes place. |
What type of hormones use intracellular receptors | Steroids and Thyroids |
What controls the level of hormones in the blood? | The rate of secretion vs. the rate of clearance; and Negative feedback mechanisms |
What are 3 ways that hormones are cleared? | They bind to their target tissue and get degraded; They get excreted in the urine; They get broken down by enzymes in the liver and excreted in bile |
If a hormone is bound to a protein is it active? | No, only the free form of the hormone is active |
Where is the pituitary gland located? | At the base of the brain in the sella surcica |
What is the other name for the anterior pituitary gland? | Andenohypophysis |
What hormones are secreted by the anterior pituitary gland? | GH, Prolactin, TSH, ACTH, FSH, LH |
What receptors do anterior pituitary glands act on? | Cell Membrane Receptors |
What is another name for the posterior pituitary gland? | neuronalhypophysis |
What hormones are secreted by the posterior pituitary glands? | ADH and Oxytocin |
Where are ADH and Oxytocin Made | Hypothalmus |
What connects the Hypothalmus to the Anterior Pituitary Gland | The hypothalmus-hypophyseal portal system |
What connect the Hypothalmus to the posterior pituitary gland? | Nerves that originate in the hypothalmus terminate in the posterior pituitary gland |
Hypothalmic Releasing Hormones | GHRH, TRH, CRH, Gonadotropic RH |
GHRH | Stimulates Anterior Pituitary to release GH |
TRH | Stimulates Anterior Pituitary to release TSH |
CRH | Stimulates Anterior Pituitary to Release ACTH |
Gonadotropic hormone | Stimulates Anterior Pituitary to release LH and FSH |
Hypothalmic Inhibitory Hormones | GHIH (somatostatin), prolactin inhibitory hormone |
Somatostatin | Decrease GH secretion, Decrease insulin and glucagon secretion, decreased gastric secretion, decrease absorption of nutrients |
When is GH (somatotropin) at its highest levels? | 1-4 hours after sleep, During Anxiety, during exercise, during starvation (protien sparing) |
What Causes ADH to be secreted? | Osmorecepters detect hyperosmolarity; blood volume decrease by 10%; |
What causes ADH secretion to be decreased? | ETOH; Stress; Increase in Blood bolume; Decrease in Osmolarity |
Where in most ADH made? | Supraoptic nuclei in the hypothalmus |
What are the effects of oxytocin? | Milk let-down; contraction of the pregnant uterus |
Where is Oxytocin made? | The paraventricular nuclei in the hypothalmus |
What controlls the release of oxytocin? | Neuroendocrine reflexes such as tactile nipple stimulation (suckling), stretch in early labor |
What hormone does the pineal gland secrete? | Melatonin |
What effects melatonin levels? | Increased light = Decreased melatonin; Decreased Light = Increased Melatonin |
Function of Melatonin | Reproduction; Sleep inducer, helps with jet lag; immune booster, tumor supressor; use in clinical depression |
Steps in Thyroid Hormone Formation | Idodide is pumped out of the blood stream and into the thyroid (Iodid Trapping); The iodide is incorporated into the thyroglobulin (organification) Adjacent thyroglogulins couple to form thyroxine (Coupling) |
T3 | Triiodothyronine |
T4 | Thyroxine |
How is Thyroid Hormone made into a usable form | The TH leaves the thyroid folical through pinocytosis mostly as T4. The T4 is cleaved (deiodinated) to T3 for use by the tissues |
Function of Thyroid Hormone | Increased Metabolic rate, Increased O2 consumtion, Increased mitochondria,Increased Na-K ATPase pump, Increased Carb metabolism, Increased lipid metabolism, Increased Contractility. Causes normal Growth/Development in young |
How is thyroid hormone regulated? | The hypothalmus detects changes in the body and if TH is needed it releases TRH which causes the Anterior Pituitary to release TSH; The TSH causes the thyroid to increase production and release of T3 and T4 |
What causes an increase in TRH release | Detection of extreme cold by the hypothalmus |
What causes a decrease in TRH Release | Detection of stress and pre-existing hyper-everything state by the hypothalmus (sorry if this is confusing Abby and Nicole) |
What hormone regulates plasma calcium levels? | parathyroid hormone |
How does Parathyroid Hormone increase plasma Ca++ Levels? | Causes a decrease in the amt of Ca++ that is secreted by the kidney by reabsorbing the Ca++ from the renal tubules; Activates Osteoclasts to reabsorb Ca++ from the bone |
What is the most active form of Vitamin D in the body | 1,25 dihydroxycholecalciferol |
What are the 2 most important elements in control of Ca++ Levels | Vitamin D and PTH |
Describe Calbindin | It is a Ca++ binding protien located in the intestinal epithelial cells that aids in reabsorping of Ca++. The rate of reabsorption is directly proportional to Calbindin |
What effects does calcitonin have? | decreases serum calcium; inhibits osteoclasts |
What gland secretes Calcitonin? | Thyroid Gland |
What type of hormone is Calcitonin? | Peptide |
What are the 3 layers of the adrenal Cortex | Zona Glomerulosa (outer layer), Zona Fasciculata (middle Layer); Zona Reticularis (inner layer) |
What hormones are rleased by the glomerulos of the adrenal cortex? | Mineralcorticoids (Aldosterone) |
What hormones are released by the fasciculata layer of the adrenal cortex? | Glucocorticoids (Cortisol, Cortisone) |
What causes the glomerulos of the adrenal cortex to secrete aldosterone? | Angiotensin II |
What causes the fasciculata to secrete the glucocorticoids? | CRH -> ACTH |
What Hormones are released by the reticularis? | Adrenal Androgens (DHEA, testosterone etc) |
When is cortisol at its highest levels? | Early in the morning |
What is the function of cortisol? | Anti-inflammatory; resistance to stress; gluconeogenesis; glycogenesis; increased blood sugar; Causes amino acid mobilization of muscle (so more amino acids are available for gluconeogenesis) |
What controls the release of Cortisol | The hypothalmus senses stress, hypoglycemia, or it is morning and it releases CRH which causes the Ant. Pit. to release ACTH. ACTH converts cholesterol into cortisol in the middle layer of the adrenal cortex |
What are the effects of aldosterone? | Na+ reabsorption and K+ secretion; causes intravascular fluid volume to increase |
What causes aldosterone to be released? | Angiotensin II acts on the outer layer of the adrenal cortex causing aldosterone release (RAA negative feed back system) |
What medications will decrease aldosterone secretion? | ACE Inhibitors |
What hormones are released by the adrenal medula | Epi and Norepi |
What causes epi/norepi to be secreted? | Stress, exercise, hypoglycemia, surgery, bleeding, sympathetic stimulation |
What are the effects of epi/norepi? | mobilization of carbs; increased HR and BP |
What is the normal Glucose Level? | 80-140 mg/dL |
What 3 areas rely exclusively on glucose for energy? | CNS, Retina, germinal centers in testes and ovaries |
Where is insulin secreted from? | The beta cells on the islets of Langerhans in the pancreas |
What effects does insulin have? | Decreases blood glucose; inhibits gluconeogenesis; stimulates glycogenesis in live ard muscles; stimulates lipogenesis; causes growth |
At what time period is insulin responsible for most of the blood glucose regulation | Absorptive state (2-3 hours after eating) |
At what time period is glucogon responsible for most of the blood glucose regulation? | Post-Absorptive State (long time after eating) |
Where is glucagon produced? | The alpha cells on the islets of Langerhans in the pancreas |
What effects does glucagon have? | Causes gluconeogenesis, causes glycolysis, causes lypolysis |
What are the target tissues for glucagon? | Liver, Muscle, Adipose tissue |
How does spermatogenesis occur | GnRH is released by Hypothalmus and causes the Ant. Pit. to release LH and FSH. LH acts on the Leydig cells causing testosterone to be released. Testosterone and FSH acts on the sertoli cell to create sperm |
What Is inhibin and where does it come from? | Inhibin is secrteted by the sertoli cell and it acts on the hypothalmus to stop sectreting GnRH (neg feed-back) |
What effects does testosterone have? | Behavioral effects, androgenic effects, increased protien formation and muscle development; increased BMR; water retention |
A huge surge of which hormone leads to ovulation? | LH |
What does estrogen cause | Increase uterine growth, uterine smooth muscle, uterine endometrium, progesterone receptor content |
Where does progesterone come from? | Corpus Luteum |
What are the effects of the corpus luteum? | Supresses FSH and LH |
How is Estrogen formed | Hypothalmus secretes GnRH and causes AP to secrete LH and FSH. LH acts on the Theca cell to produce androgens that act on the Granulosa cell along with LH and FSH to form estrogens |