The exporting function of a biological unit is the function that enables the unit to bring to bear the fruits of its labor to the larger biological unit. A farmer who has a large fruit and vegetable farm is not valuable to the society if he has no mechanism of delivering his product to the market. He does not serve himself, his family nor community if the product is not deliverable. Such is the case with each biological unit – thay each have to have a mechanism to deliver their products. We will briefly introduce the exporting function of the systems in the body.
Among the many afferent functions of the brain and spinal cord we have chosen an image to represent the nerve supply of the heart. The efferent system delivers a stimulus from the sympathetic and parasympathetic systems to the sinoatrial node which subsequently progressively exports the afferent signals to the atrioventricular node and then to each of the ventricles.
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The cardiovascular system is a both receiver and exporter in its role as a major transport system in the body. Among the multitude of transport functions, it can be simply viewed as having an arterial system that takes blood away from the heart and toward the organs and a venous system that takes blood away from the organs ands tissues and toward the heart. It took our civilization many years to understand that the cardiovascular system was a circulation, reportedly discovered by William Harvey in the first half of the 17th century who noted that the exporting function and importing function were within and part of the same system.
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The respiratory system is a both receiver and exporter in its role as a major transport system in the body. Among the multitude of transport functions it removes carbon dioxide from the lungs and transports it to the outside environment. It thus also has a dual role as an exporter and importer.
The gastrointestinal system is also a major transport system and each structure along its tract both receives and exports nutritional products and waste products. The glands of digestion including the salivary glands, liver, via the biliary system, and the pancreas, all have ductal systems that enable their products to be exported to the sites of action.
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The urinary system is a both receiver and exporter in its role as a major transport system of water and electrolytes as well as nitrogenous waste in the body. Among the multitude of transport functions it removes urea from the body and transports it to the outside environment. It also has role of importing recycling and excreting water and electrolytes from the body.
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The genital system transports its products via tubes as well. The spermatazoa are exported from the testes via the vas deferens and are delivered via the urethra into the receiving vagina and cervix, while the ovum from the ovary is launched by the rupture of the follicle, and is exported to the endometrial cavity via the fallopian tubes.
The reticuloendothelial system as a part of the defense system. The lymphatics for example transport foreign material from the sites of origin to the lymph nodes where foreign sunstance is impounded. A prime example is shown n the lymphatics of the lung below where inhaled anthracotic material is shown in the lymphatics of the lung on its way to the lymph nodes. In the second image foreign material in the form of inhaled carbon and metastattic cancer have both been impounded by lymph nodes in the lung, having got there either via the lymphatics or via circulating macrophages which dumped the intruders in the lymph nodes.
The musculoskeletal system is mostly part of the transport system. It is hard to conceive the export function of the muscles for example until one thinks of muscle as an organ that contracts and relaxes. The delivery of its action is caused by the contraction since without this part of the motion the function cannot be delivered. The muscle is part of a mechanism that converts chemical energy to mechanical energy and it is the processing of the chemical energy and its setting up of the contractile elements that are part of its processing action while the contraction and subsequent relaxation is part of its delivery of services.
The following tragic case of a bullet wound to the spinal cord resulting in quadraplegia. The consedemonstrates the effect on the body including the muscular and skeletal system when they cannot function because of a control system that is non functioning. The inabilty of the muscles to be able to relax, results in flexion contractues, and total inability to use the hands arms and legs. This injury therefore results in the inability of the patient to stand, move or support the body, and the patient is ommitted to bed or wheel chair resulting in bed sores and consequently bone infection if obssessive skin care is not administered. The inability to evacuate or void result in constant constipation and the need for a suprapubic catheter to empty the bladder.
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