Human Digestive and Respiratory Systems: Functions and Diseases
1. Apparatus Involved in Nutrition
Through their combined action, the body’s systems incorporate nutrition and nutrients used to maintain an optimal functional state. Nutrition is a complex process involving different systems of our body: the respiratory apparatus, the digestive system, the circulatory system and the excretory system.
- Digestive system: is responsible for breaking down food and turning it into simpler substances.
- Respiratory system: deals with gas exchange and provides oxygen.
- Circulatory system: its role is to transport oxygen and usable food substances through the blood to the various cells of our body, where they will be used.
- Excretory system: is responsible for eliminating waste substances from the blood it transports.
2. Digestive Functions
These functions allow food, as it passes through the digestive tract, to be processed into nutrients that are transportable to the cells where they will be used.
- Ingestion: the entry of food into the digestive tract through the mouth.
- Digestion: cutting, crushing and breaking down food.
- Absorption: the process by which nutrients from digestion cross the digestive tract wall.
- Egestion: elimination of substances that are not digestible or not absorbable from food.
3. Digestive System Diseases
- Dental caries: an infectious disease caused by bacteria that affects the hard tissues of the tooth.
- Constipation: a disorder characterized by difficult evacuation of feces.
- Ulcers: open wounds on the inner walls of the digestive tract.
- Gastroenteritis: inflammation of the membranes lining the stomach and intestine.
- Liver cirrhosis: a chronic disease involving progressive death of liver tissue, which leads to poor liver function.
4. Gas Exchange
Gas exchange (oxygen and carbon dioxide) between the internal and the external environment takes place in the pulmonary alveoli.
5. Pulmonary Ventilation
Pulmonary ventilation is the process by which atmospheric air enters the interior of the lungs and then leaves them to the atmosphere.
Inspiration and expiration:
Pulmonary ventilation is accomplished through two movements: inspiration, which brings air into the lungs, and expiration, which expels air to the outside.
6. Respiratory Tract Diseases
- Bronchitis: inflammation of the bronchi, often due to bacterial infection.
- Asthma: temporary narrowing of the airways that causes oxygen deficiency in tissues and hampers respiration.
- Tuberculosis: a contagious disease caused by bacteria that destroys lung tissue.
- Influenza (flu): a highly contagious infection of the airways caused by a virus.