SA Medical - General Medicine And Imaging of Disease

Three basic patterns of endocrine pathologies: Hormone excess, Hormone deficiency, and abnormal responsiveness of target tissues to a hormone. CRH-ACTH-Cortisol-Target Tissue-Response Hypersecretion Exaggerates a Hormones Effects Adenomas may cause hypersecretion. Tumours, including non-endocrine tumours may secrete hormones. Exogenous source of hormones, eg Exogenous Cortisol. Prolonged use may cause cellular atrophy. Hyposecretion Diminishes or Eliminates a Hormones Effects Most commonly due to atrophy of the endocrine gland. Adrenal Gland atrophy secondary to tuberculosis, diminishing cortisol production Receptor or Second Messenger Problems Cause Abnormal Tissue Responsiveness Downregulation Hyperinsulinemia - sustained levels of insulin cause the insulin receptors of target tissues to remove insulin receptors from the cell membrane. Patients suffering from hyperinsulinemia show signs of diabetes despite their high insulin levels. Receptor and Signal Transduction

Pathology of the skin is basically the same as those that occur in other organs. The changes that can be seen with the naked eye correlates well with that seen microscopically. The evolution of skin lesions can be readily followed by repeated biopsy. The major functions of skin include sensory perception, protection against mechanical trauma, UV light and infection, insulation and temperature control, conservation of fluid, biosynthesis and  excretion and aesthetic function. The morphology of the skin that appears simple at first sight is as complex and diverse as the 10 major functions of the skin - depending on the site, sex, age, race and environment. Skin Biopsy: Select a site - not too early or too late but a fairly early representative lesion.  Full thickness skin including the subcutaneous fat. The tissue is not to be grasped with forceps but a Gillies Hook (see below) to raise and maintain tension on the skin during removal.   Orientating the excised skin is important -