SA Medical - General Medicine And Imaging of Disease

A hormone is classically defines as a chemical that is secreted into the blood and acts on a distant target in very low concentrations. Hormones can be classified according to source or location - heart, liver, pineal gland, hypothalamus, pituitary, thyroid, parathyroid, thymus, pancreas, adrenal cortex, adrenal medulla, kidney, skin, testis, ovaries, adipose tissue, and placenta. Hormones can be divided into 3 main chemical classes: Peptide and protein hormones composed of linked amino acids Steroid hormones are derived from cholesterol The amine hormones are derivatives of tryptophan or tyrosine Most hormones are Peptides or Proteins If a hormone is not a steroid or a amine it is probably a peptide. A steroid-producing cell would have extensive smooth Endoplasmic Reticulum; a protein-producing cell would have lots of Rough Endoplasmic Reticulum. Usually made in tissues all over the body unlike steroids that are made only in a few organs Peptide Hormone Synthesis, Storage a

Hormones: regulate the internal environment in three ways - by controlling the rates of enzymatic reactions, by controlling the transport of ions or molecules across cell membranes by controlling gene expression and the synthesis of proteins. The internal environment controlled by hormones include: growth and development  metabolism regulation of the internal environment (temperature, water balance, ions), and  reproduction Graves Disease: Tired and weak, loosing weight, and hot flushing. Hyperthyroidism. Increased appetite. Goiter: Enlarged thyroid gland, lack of iodine DM: Polyuria, Polydipsia, and Polyphagia. Castration:  reduced sex drive and rendered males infertile, less aggressive. Testis may be implanted and will continue to function as it is under hormonal control. Organotherapy: Hypothyroidism treated with injected thyroid Hormones: Glands Pineal gland - Amine - Melatonin has unclear targets,  Circadian rhythms Thyroid - Amine / Peptide -  Triiodot