In general, there are three stages leading from iron deficiency to anemia: 1  First, there is an insufficient supply of iron, which causes iron stores in the bone marrow to be depleted. This stage generally has no symptoms. 2  Second, iron deficiencies develop and begin to affect hemoglobin production.
Surfactant immune function is primarily attributed to two proteins: SP-A and SP-D. These proteins can bind to sugars on the surface of pathogens and thereby opsonize them for uptake by phagocytes. It also regulates inflammatory responses and interacts with the adaptive immune response.
Without normal pulmonary surfactant present, the attractive forces of the water will cause the alveoli to collapse. Pulmonary surfactant is a complex substance in the lungs which reduces the surface tension of water and therefore, prevents the collapse of the alveoli.Surfactant also plays a role in defending the lungs from bacteria and viruses.ithout normal pulmonary surfactant present, the attractive forces of the water will cause the alveoli to collapse. Pulmonary surfactant is a complex substance in the lungs which reduces the surface tension of water and therefore, prevents the collapse of the alveoli.