Blood

Overview

Blood is the general term given to the fluid circulating within a living organism, delivering essential nutrients, oxygen, and other vital chemicals throughout the body. It is characterized as a liquid substance, and its presence is critical to the survival of most species. Blood also facilitates the removal of waste products, supports the immune system, and, in many cases, aids in thermoregulation. Losing a significant amount of blood often results in death, emphasizing its importance to life processes.

While most species have specialized structures such as blood vessels to transport this fluid, others, particularly non-vertebrates, may have body cavities filled with blood or analogous fluids.

Functions

Blood performs several essential functions across both terrestrial and alien species:

Transport: Blood carries oxygen from respiratory organs to tissues, nutrients from digestion to cells, and hormones to target organs.
Regulation: It plays a role in maintaining pH balance, temperature regulation, and homeostasis.
Protection: Blood supports the immune system by transporting white cells, antibodies, and other immune factors to combat pathogens.

Alien Adaptations

Blood characteristics vary across the Galaxa universe, reflecting the environments and physiology of the species:

Extreme Temperature Tolerance:
- Grelian blood contains antifreeze-like proteins, allowing them to thrive in sub-zero aquatic environments.
- Valorèin blood carries psionic signals, allowing faint emotional or sensory connections within a family unit, especially between mother and child.
Adaptive Pigmentation:
- Sluggo blood shifts shades depending on oxygen levels, a feature used to gauge health within their species.
Unique Metallic Appearance:
- Valorèin blood is a striking metallic red, resembling liquid metal. This visual characteristic is a result of specialized proteins and metallic ions that enhance oxygen transport and regeneration.

Trivia

Blood color can range from red (iron-based hemoglobin) to blue-green (copper-based hemocyanin) to even translucent photonic plasma in crystalline species like Aenorians.
Valorèin blood is a deep metallic red, shimmering like liquid metal. This trait has inspired numerous artistic depictions of their species throughout history.
The Valorèin species have a blood protein that allows them to remain active for weeks without sleep, a trait attributed to their historical survival in war.
The Zytherian species, an insectoid race, use hemolymph enriched with trace metals that enhance their exoskeletal strength.