Physio Exam 5

• Negative feedback for thyroid hormone

  Hypothalamus releases: TRH (thyroid releasing hormone)

  Anterior pituitary releases: TSH (thyroid stimulating hormone)

  Target organ: thyroid gland

  Outcome: t3 + t4
• Function of t3 and t4

  • Stimulates production of sodium potassium ATPase, RNA polymerase, and beta adrenergic receptors
  • Stimulates metabolism of lipids and carbohydrates
• What is the RNA polymerase responsible for?

  transcription to make mRNA for proteins
• Why are adrenergic receptors important?

  sympathetic nervous system
• What is the metabolism of lipids and carbohydrates?


  Breaking them down to make energy
• Negative feedback for cortisol hormone

  Hypothalamus releases: CRH (cortical releasing hormone)

  Anterior pituitary gland releases: ACTH (adrenal cortical tropic hormone)

  Target organ: Adrenal gland

  Outcome: Cortisol
• Function of cortisol

  • Store fat
  • inhibits innate immune system, decrease in inflammation (more likely to get sick)
  • Breakdown glycogen in skeletal muscles
  • Making of glycogen in the liver
• Negative feedback for testosterone, estrogen and progesterone

  Hypothalamus releases: GNRH (Gonado releasing hormone)

  Anterior pituitary gland releases: LT (lutenizing hormone) and FSH (Follicle stimulating horomone)

  Target organ: Gonads (Ovaries/testes)

  Outcome:

  Testes LH - testosterone

  Testes FSH - spermogenesis

  Ovaries LH - progesterone, estrogen

  Ovaries FSH - oogenesis
• Feedback for milk production

  Hypothalamus releases: PRH (prolactin releasing hormone)

  Anterior pituitary gland releases: PRL (Prolactin)

  Target organ: Mammillary glands

  Outcome: Milk production
• What does somatostatin inhibit?

  Anterior pituitary gland
• Negative feedback for IGF-1

  Hypothalamus releases: GHRH (growth hormone releasing hormone)

  Anterior pituitary gland releases: GH (growth hormone)

  HAS inhibitor: somatostatin

  Target organ: Liver, muscles, bones Outcome: IGF-1 (insultin growth factor, binds on insulin receptors)
• Function of IGF-1

  • Preventing apoptosis (programmed cell death)
  • cells will live longer
  • Increase cell division (mitosis)
  • more cells
• Function of the endocrine system

  Release of hormones into bloodstream
• Endocrine system

  • Long term
  • Long distance
  • Slow communication, long-lived
• What does the endocrine system use as a signal?

  Hormones = chemical that is created by cells and secreted in the blood to communicate to distant cells
• How do we “sense” hormones?

  Receptors
• Differences between peptide hormones and steroid hormones

  Peptide hormones: Chain of amino acids (hydrophilic, non-polar), can dissolve great in blood

  Steroid hormones: Lipid (hydrophobic, non-polar)
• Pituitary gland

  • Secretes hormones based on signals from hypothalamus called releasing hormones
  • anterior pituitary is an endocrine gland and secretes 6 hormones
  • posterior is made of nervous tissue and secretes 2 hormones made by hypothalmus
• Hypothalamus function

  Maintain homeostasis
• Too much t3 + t4

  • Lots of metabolism
  • Weightloss
  • Fatigue
  • Nervous/anxious (sympathetic nervous system, heart rate goes up)
  • activates more adrenergic receptors
• Too much IGF-1


  Excessive growth, can result in cancer
• Too little somatostatin

  • Take longer to stop producing GH and GHRH
  • therefore, produce more IGF-1 and more development in muscle/bone
  • Can’t get rid of old cells
• Too much somatostatin

  • Lacking in muscle/bone developement
  • Not producing enough IGF-1