The Gastro Intestinal Tract The Liver

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2.7 The Gastro Intestinal Tract

The gastrointestinal tract is the system used by the body to take in, break down and absorb nutrients as well as to excrete waste products. Ingestion as a toxic route of entry in industry is unlikely, but it can occur if people are allowed to eat or smoke at their work station thus risking contamination from their hands or from contaminated surfaces. Both vomiting and diarrhoea are natural defence mechanisms against ingested toxins, and gastric acid will neutralise alkaline intruders to an extent and also kill bacteria. Absorption of toxins is relatively less efficient than via inhalation, also limiting body entry. Nevertheless, any irritant or corrosive agent which could affect the mucous membranes of the respiratory tract can also cause swelling of the lips, mouth and epiglottis leading to choking and ulceration of the oesophagus and stomach. Source: Wikimedia Commons Figure 2.7 – The Gastro Intestinal Tract 32

2.8 The Liver

The liver is a major metabolic organ which is used to process nutrients which have been absorbed into the blood from the gastrointestinal tract or via other routes such as inhalation. The fact that it is used to break down materials means that is particularly susceptible to any toxins within the body. Liver cells can regenerate after toxic damage, the most common cause of which is alcohol. However, continued absorption can overtake the regeneration process and cause permanent liver damage. Pre-existing liver disease makes this more likely. Industrially, fat-soluble alcohols and halogenated hydrocarbons are particularly known for their liver cell damage. The most obvious sign of liver damage is jaundice. Liver damage, usually cirrhosis, is an important precursor of hepatomas liver tumours and thus industrially induced long-term liver damage predisposes employees to liver tumours. The liver is a protective organ itself in that its normal detoxification processes change potential toxins to safe forms and sometimes vice versa. Source: Wikimedia commons Figure 2.8 The Liver 33

2.9 Urinary System