Bio-Tech: Digestive and Filtration Modifications

The body's digestive system is designed to transform food into protein, vitamins, minerals, carbohydrates, and fat which can be absorbed into the bloodstream to power the body. After being chewed and moistened by saliva, food goes down the esophagus into the stomach, where it is digested by stomach acids. It then passes into the small intestine (the longest part of the digestive system), where it is transformed into nutrients and absorbed into the bloodstream along its vast surface area.

Nutrient-rich blood enters the liver for processing. It filters out harmful substances or wastes, turning some of the waste into bile (which is used to break down fatty foods). The large intestine handles the remaining waste. It absorbs water and any remaining minerals, concentrating the remaining soup into solid waste and storing it in the rectum. The large intestine teems with symbiotic microbes which assist the process.

Modifications to the liver are usually aimed at selectively improving its metabolic and detoxification abilities, giving better resistance to blood toxins (including alcohol), usually in conjunction with modifications to the spleen and kidneys. This is represented by being Resistant to Poison or perks such as Alcohol Tolerance. It may also be possible to rebuild the liver so its tissues store oxygen, in the manner of some marine mammals (see Respiratory Alternatives).

General improvements to the digestive and urinary system can give the advantage Reduced Consumption; digestive improvements provide Reduced Consumption (Food).

A common modification, especially for pantropic parahumans who are adapted to an alien world or postholocaust environment, is Immunity to a specific poison, where the poison is a particular environmental condition in air, water, or food. This is usually TL9, although some conditions might require higher-TL modifications.

Colonists, scouts or soldiers who have to live off the land might have an intestinal tract redesigned to function like that of a ruminant animal (e.g., a cow), with symbiotic bacteria that can digest cellulose, allowing them to eat almost any plant matter. This ability is Reduced Consumption (Cast-Iron Stomach). Going the other way, it might be desirable to remove as many parasitic and symbiotic bacteria as possible from the human body, giving Sanitized Metabolism. Spacers may take this route to reduce the risk of bacterial infection or mutation in fragile and radiation-exposed space ecosystems. If so, the newly-sanitized intestines will need to be modified to produce enzymes that handle the functions of intestinal bacteria, such as vitamin synthesis.

The appendix is a vestigial growth on the end of the intestine. In humans, it doesn't do much except become infected; human gengineers may remove it in the interests of boosting overall health and resistance to disease. In and of itself, No Appendix is only a feature, but it is often taken in conjunction with an overall increase in HT.

The body's water processing system is the urinary system; its main organs are the kidneys, which contains a million tiny filters (nephrons) that remove waste products including excess salt and water from the blood into the bladder, for release. The kidneys could be remodeled after a desert animal's to conserve water via super-concentration of the urine (which would also reduce the need for bathroom breaks). This results in the need for only 2/3 to 1/3 as much water. This ability provides Reduced Consumption (Water Only).

Digestive and Filtration Modifications

Trait	Cost	TL
Alcohol Tolerance	1	9
Immunity to a Specific Poison	1	9
No Appendix	0	9*
No Hangover	1	10
Reduced Consumption 1-2	2/level	10*
Reduced Consumption 3	6	11*
Reduced Consumption 4	8	12*
− Food Only -50%	-1
− Water Only -50%	-1
Resistant
− to Ingested Poison (+3)	3	9
− to Ingested Poison (+8)	5	10*
− to Poison (+3)	5	10
− to Poison (+8)	7	11*
Sanitized Metabolism	1	9*

* Species modification.