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.
Lung
This can disrupt the normal physiology of the lung and predispose to respiratory diseases. 
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.
wiki:19605761
Lung [SEP] Vitamin A deficiency
The developing lung is particularly vulnerable to changes in the levels of vitamin A. Vitamin A deficiency has been linked to changes in the epithelial lining of the lung and in the lung parenchyma. This can disrupt the normal physiology of the lung and predispose to respiratory diseases. Severe nutritional deficiency in vitamin A results in a reduction in the formation of the alveolar walls (septa) and to notable changes in the respiratory epithelium; alterations are noted in the extracellular matrix and in the protein content of the basement membrane. The extracellular matrix maintains lung elasticity; the basement membrane is associated with alveolar epithelium and is important in the blood-air barrier.