Gastrointestinal tract endocrine function

The circulatory system carries out many important functions that contribute to homeostasis. It obtains oxygen from the lungs nutrients from the gastrointestinal tract and hormones from the endocrine glands and it delivers these substances to the tissues that need them. Furthermore, it removes metabolic waste products, such as carbon dioxide, lactic acid, and urea, from the tissues. Finally, it contributes to the actions of the immune system by transporting antibodies and leukocytes to areas of infection. Overall, the circulatory system plays a vital role in maintenance of optimal conditions for cell and tissue function. 

The results of commonly employed laboratory tests are usually normal. Even liver function tests are only occasionally altered except during episodes of jaundice. It is striking that little or no evidence of metabolic or endocrine malfunction is detectable even in cases with massive infiltration of pancreas, liver, gastrointestinal tract, heart, kidneys and adrenals with lipid-laden cells, supporting the contention of Let-TERER (1939,1947) that storage by cells is not correlated with impairment of function. 

The epithelium (the biological and medical collective term for covering and glandular tissues) is composed of layers of cells that line the outside and inside surfaces of organs. The outermost layer of the skin is composed of stratified squamous epithelial cells, while other epithelial cells line the insides of the respiratory, gastrointestinal, reproductive and urinary tracts, and also comprise the exocrine and endocrine glands. The functions of epithelial cells include secretion, absorption, protection, transcellular transport, sensation detection and selective permeability. The endotheUum-the irmer lining of blood and lymph vessels-is a specialized form of epithelium. 

Pulmonary COPD, skeletal disorders which may restrict respiratory function Endocrine Addison s disease, thyroid dysfunction Gastrointestinal hepatic impairment, biliary tract impairment... 

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