what are the various illnesses one can get if this respiratory organ is infected in humans?
Pneumonia, bronchitis, tuberculosis, bronchiolitis, to name a few.
Lung
Inflammatory conditions of the lung tissue are pneumonia, of the respiratory tract are bronchitis and bronchiolitis, and of the pleurae surrounding the lungs pleurisy. Inflammation is usually caused by infections due to bacteria or viruses. When the lung tissue is inflamed due to other causes it is called pneumonitis. One major cause of bacterial pneumonia is tuberculosis. 
what are the function of lungs in human body Their function in the respiratory system is to extract oxygen from the atmosphere and transfer it into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere, in a process of gas exchange. how is this right organ different from the left organ in humans? The right lung is bigger and heavier than the left. what type of tissue is this respiratory organ made up of? Its connective tissue is made up of elastic and collagen fibres that are interspersed between the capillaries and the alveolar walls. from where does this respiratory organ get its blood supply? Bronchial and pulmonary circulation. what is that second circulation all about? It is the portion of the circulatory system which carries deoxygenated blood away from the right ventricle, to the lungs, and returns oxygenated blood to the left atrium and ventricle of the heart. how does that type of circulation take place in that respiratory organ which we are talking about? The circulatory system of the lungs is the portion of the cardiovascular system in which oxygen-depleted blood is pumped away from the heart, via the pulmonary artery, to the lungs and returned, oxygenated, to the heart via the pulmonary vein. when does that respiratory organ first develop in humans? UNANSWERABLE can you give me examples of some spineless animals in which this respiratory organ is present? Spiders, scorpions, coconut crab,  land snails and slugs. what happens to this organ if there is a deficiency in vitamin a? It can disrupt the normal physiology of the lung and predispose to respiratory diseases.
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Lung [SEP] Inflammation and infection
Inflammatory conditions of the lung tissue are pneumonia, of the respiratory tract are bronchitis and bronchiolitis, and of the pleurae surrounding the lungs pleurisy. Inflammation is usually caused by infections due to bacteria or viruses. When the lung tissue is inflamed due to other causes it is called pneumonitis. One major cause of bacterial pneumonia is tuberculosis. Chronic infections often occur in those with immunodeficiency and can include a fungal infection by "Aspergillus fumigatus" that can lead to an aspergilloma forming in the lung.