The Core Services consist of the networks running throughout the body that are necessary for supplying nutrients, energy and communication, and waste-removal.
In other words, the blood supply, peripheral nervous system, and lymphatic system, plus electrical power for the parts that need it.
The general idea is to continue the theme of biological components being enclosed in non-biological protective materials by having flexible pipes that contain up to four different channels, two for liquids: Blood and Lymph, and two for wiring: electrical power and electronic or optical communication signals.
It might make sense to separate these two kinds of channel, as the electrical/optical channels have different requirements to the fluid ones, and will be attached to non-biological as well as biological components, so may need different routing.
The blood vessels - arteries and veins - are of two types, global and local. Global vessels travel between different parts of the body, linking together the different organ modules, muscle modules and the CNS. Local vessels are entirely within modules.
The local circulation is part of the biology of the modules. Creating vascular beds in tissues is discussed in Organ Building. The global circulation, being outside the modules, needs to be encased in a non-biological layer, following the overall design principle. There are a few different possible approaches to this. The simplest, but least likely to be a good choice, is just to use plastic piping. The main problem with that is the reaction of the blood to the polymer. Several defence mechanisma will inevitably be triggered in the blood, including clotting and activation of various parts of the immune system such as complement, platelets and various lymphocytes.
To avoid this, a better approach would be to coat the inside of the piping with a layer of some substance that avoids provoking these reactions. Collagen, various biopolymers and gels might work.
A third approach involves keeping the normal blood vessel structure and coating it in a synthetic polymer. This means growing entire blood vessels with their various layers of epithilium, muscle and connective tissue.
An intermediate solution would be to create a layer (or several layers) of epithelial cells that adhere to the inner surface of the piping:
The techniques discussed in Biocompatibility would be used for this.
The blood vessels (for venous and arterial blood) would be packaged together with other core services components (lymph vessels, an possibly Peripheral Nervous system and power lines) in service channels which could have tough outer coverings.
Electrical power will be needed for some parts of the body, particularly the neural interfaces, computing, and sensory systems.
Power storage, backup storage will be the main challenges. Distribution can be via simple wires.
Rechargeable batteries, fuel cells, supercapacitors and piezoelectric generators all seem feasible. Multiple redundancy will be essential, as power failure would mean total loss of sensation, motor control and communication.
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