Exam 5/3

• Thymus gland


  • Located deep to the sternum
  • Its major hormonal products are thymopoietins and thymosins, which are essential for the development of T lymphocytes (T cells) of the immune system
• Oxytocin


  • Stimulates smooth muscle contraction in breasts and uterus
  • Is a strong stimulant of uterine contraction
  • Leads to increased intensity of uterine contractions, ending in birth
  • Triggers milk ejection ("letdown" reflex) in women producing milk
• 2nd messenger systems in hormone control, ions involved

  • Regulatory G proteins and Amino acid-based hormones
  • Adenylate cyclase (AC) generates cAMP (second messenger) from ATP
  • Ion involved calcium ions (Ca3)
• Eicosanoids


  • Biologically active lipids with local hormone–like activity
  • Types of hormones in Eicosanoids are leukotrienes and prostaglandins
• Hormone interactions

  • Permissiveness - one hormone cannot exert its effects without another hormone being present
  • Synergism - more than one hormone produces the same effects on a target cell
  • Antagonism - one or more hormones opposes the action of another hormone