The overall function of the digestive system as digestion and absorption of food stuffs, and the general activities of each digestive system organ is; Ingest, digest, absorb, defecate. Ingestion involves placing food into the mouth, propulsion involves propelling food from one organ to the next using peristalsis. Mechanical digestion involves the physical fragmenting food into smaller particles. Chemical digestion refers to breaking down food molecules to building blocks by enzymes. Absorption is the transport of digested end products to blood or lymph; and finally Defecation which involves the elimination of indigestable material from GI tract by anus.
Explanation: Alveoli of lungs are surrounded by extensive blood capillaries. The partial pressure of oxygen in the alveoli is higher than the blood entering the pulmonary capillaries, hence oxygen moves into the blood. Carbon dioxide in the lungs simultaneously diffuse out of the blood into the alveolar space.
Serious systemic fungal infections and parasitic infections usually only develop in individuals who are immunocompromised. These individuals have a weak immune system. The body cannot respond quickly to infections since their immunity is not very well developed.
