For full documentation and explanation, visit the Youtube demo video.

The material consists of a single shader with 12 inputs and 3 outputs, described in detail below. It also has a mapping node for custom mapping vectors and two distinct material outputs: one for Cycles and one for Eevee. The differences with the output material are minimal for each render engine, but make it look a bit better. When using either engine it is important to select the right material output in the shader editor (click on the red material output node that says the name of the render engine).

INPUTS:     (all inputs can be a single value or a custom map/texture.)

1. Vector: Input vector coordinates (as standard in any texture node).
2. Color Correction: The color you want to pull the material towards. Can be a single RGB color or a custom input image/texture node.
3. Scale: Scale of the material (as standard in any texture).
4. Distortion: Distortion of large bump structure. Increasing this makes the veins less straight.
5. Bump Scale: Scale of large bumps (explained in next item), relative to other structures such as small bumps and veins.
6. Large Bumps: Magnitude (height) of large bumps. Large bumps are the voronoi-like bumps between the veins.
7. Small Bumps: Magnitude (height) of small bumps. Small bumps are the slight noise bumps of much smaller scale than the large bumps.
8. Veins: Height of veins.
9. Veins Extension: How far the veins extend into the tissue.
10. Roughness Adjustment: Relative offset for the roughness based of the default value. -1 is fully glossy and +1 is fully matte.
11. Clearcoat: Clearcoat over the material, used to make the wet look.
12. Striations: Small long wave texture that follows the path of the veins (more visible close to veins).

OUTPUTS:

1. BSDF (Cycles): BSDF shader to plug into the Surface input of the Material Output node. Better results for use in Cycles render engine.
2. BSDF (Eevee): BSDF shader to plug into the Surface input of the Material Output node. Better results for use in Eevee render engine.
3. Displacement: Discpacement vector map to plug into the Displacement input of the Material Output node.

To get true displacement in Eevee, it is necessary to bake the displacement texture onto an image and use the image as the texture on a Displace modifier. Explained in detail in this demo video: https://youtu.be/-Vu3_4HZm3g