Typed Lecture Notes

• Endocrine system


  Consists of glands that secrete hormones
• Hormones


  Chemical messengers that maintain homeostasis by sending signals to other organs to release a different hormone or to have a different action
• Negative feedback loop


  When hypothalamus or pituitary receive the message that there is not enough of the hormone or substance its looking for, it creates & releases a lot of the precursor hormones that stimulate the second organ to make the hormones & release them into the blood stream & back up to the hypothalamus & pituitary

  
• One hormone may control another hormone
• Hypothalamus & pituitary

  • They are very dependent on perfusion to the brain
  • If we don't have good blood flow going there, they can't do what they are supposed to do
• Hypothalamus


  The master gland, so when it doesn't receive the information that it needs, it will release those precursor hormones to the pituitary & to the other glands

  
• Parathyroid glands


  Pea like organs that live inside the thyroid
• Neck injury or not getting good blood flow to thyroid; good possibility that the parathyroid isn't working either
• Thymus gland


  Usually more predominant in children, adults have kind of outgrown the need for it
• Adrenal glands


  Sit on top of kidneys
• Kidneys are responsible for fluid volume management, filter out toxins, & adrenal sitting on top depends on the blood flow it gets the same as kidneys
• Drugs that come from adrenal medulla


  • Adrenaline
  • Epinephrine
  • Norepinephrine
• Adrenal cortex


  Produces corticosteroids

  
• Negative feedback


  Common for last hormone in a pathway to provide feedback
• Regulation of serum calcium levels

  1. As serum calcium levels fall, PTH is released from the hypothalamus

  2. PTH causes an increase in serum calcium, pulls calcium out of the bones so there is more calcium circulating in the blood stream

  3. Provides feedback to the parathyroid glands to shut of PTH secretions
• Hormone pharmacotherapy


  Hormones used for replacement therapy, antineoplastics, and natural therapeutic effects
• Hormone blockers "anti hormones"


  Used to inhibit actions of certain hormones
• Tamoxifen acts as the "safety plug" in an electrical outlet so no little fingers can get in & cause harm
• Corticosteroids


  • Glucocorticoids
  • Mineralocorticoids
• Corticosteroids in their own way, do a lot of the same things by causing flight or fight symptoms
• Cushing syndrome


  Hypersecretion of corticosteroids
• Addisons disease


  Hyposecretion of corticosteroids
• Parathyroid glands


  Secrete PTH, responsible for vitamin D & calcium metabolism
• Calcium is important for good rhythmic muscle contractions
• Parathyroid is essential for cardiac function
• Hyperparathyroidism


  Hypersecretion of PTH
• No drug therapy for hyperparathyroidism, the parathyroid glands are removed as well as sometimes most of the thyroid is removed as well

  
• Hypoparathyroidism


  Hyposecretion of PTH
• Treatment of hypoparathyroidism


  Give human parathyroid hormone (Natpara), vitamin D, & calcium supplements
• Pituitary gland


  Secretes ADH, GH, & oxytocin
• ADH


  Prevents patient from losing water
• SIADH


  Syndrome of inappropriate antidiuretic hormone, hypersecretion of ADH leading to holding onto too much water
• Diabetes insipidus


  Hyposecretion of ADH leading to losing a lot of water
• Desmopressin (DDAVP)


  Used to treat diabetes insipidus
• Growth hormone


  If brain isn't getting perfusion it needs, it will effect growth hormone secretion
• Small stature


  Hyposecretion of growth hormone in children
• Somatotropin


  Man made growth hormone given to children who are not growing to expectation
• Acromegaly


  Hypersecretion of growth hormone in adults
• Hypothalamus


  Secretes releasing hormones that travel to the pituitary gland to specify which hormone should be released

  
• Posterior pituitary


  Releases hormones in response to nerve signals from hypothalamus