Cell Signalling - Monday, May 6

Cell Signalling

Gland - Any structure that secretes a hormone.
Hormone - Any chemical secreted by one part of the body that has its effect/s somewhere else. Two basic Types:
      1. Steroid (Fat-based - non-polar - can diffuse through cell membranes)
      2. Peptide ("Protein" - polar - bond to a receptor protein on cell surface). Pheremones - chemicals excreted by one individual that cause a physiological change in another individual.
  
I. Gonads - Primary sexual structures
           A. Ovaries - produce estrogens & progesterone - responsible for female structure, menstral cycle & pregnancy.
           B. Testes - Testosterone. Responsible for male anatomy, sperm production. How is it regulated? By the hypothalmus (Part of the brain - made up of Neurons) Pituitary (true gland) Negative Feedback System (HPNFS)
      1. Hypothalamus - raises levels of GnRH (Gonadotropin Releasing Hormone)
      2. Pituitary - is signalled by higher levels of GnRH to release LH (a gonadotropin)
      3. Testes - are signalled by higher levels of LH to produce higher levels of Testosterone.