>>19139860
Brain: The brain is tetraspheric, i.e. composed of four major sections. The sections are separated by transverse and longitudinal fissures and are connected to the central lobe, which acts as brainstem and cerebellum. The volume of the brain is around 20% superior to that of a man of the same height. It has a much more pronounced level of gyrication than an average human. Moreover, the ratio of glial cells to neurons is also slightly higher than in humans. It is important to mention the presence of nodules on the central lobe. Histological analysis of these structures reveals a kind of intricate biological circuitry. It is speculated that these nodules are essential to interact with their technology. Consequently, determining the proteome of these structures is an absolute priority for the program.
Neck: The neck is proportionally longer than that of a human, and at the same time relatively thin. As mentioned, the esophagus and trachea are separate. There are no vocal cords in this region.
Thorax: The musculature of the thorax is underdeveloped. Muscles equivalent to the pectoralis major can be seen. We can also see the trapezius and deltoid muscles. The sternocleidomastoids are well defined. The ribs and sternum are clearly visible. There are no nipples.
Abdomen: The abdomen is wider than the thorax and bulges slightly forward. There is no navel.
Pelvis: The pelvic bones are apparent. There are no genitals or anus.
Hands and feets: Their hands have four digits, including an opposable thumb on the medial side. They have no nails, and the texture of their fingerprints is composed of concentric circles. Fingers are proportionally much longer than in humans. Unlike humans, finger musculature is entirely intrinsic to the hand. In other words, the muscles used to move the fingers are not in the forearms but entirely located in the hands. At first glance, the feet consist of just two digits, but a necropsy soon determined that each toe was made of two fused digits. The medial toe is marginally longer than the distal toe. The feet are relatively longer and narrower than in a human. Their musculature, however, is vestigial.
The EBOs endoskeleton is very similar to ours, at least in terms of composition. There's collagen, hydroxyapatite but also copper oxide crystals where marrow would normally be found. The role of these crystals has not been established, but it is not a crystalopathic condition. The blood cells of the myeloid lineage (or the equivalent for these creatures) therefore mature in a different location than in humans i.e. in the thymus like organ. A transverse section of the bone reveals osteon and osteocytes. There appear to be few osteoblasts and no osteoclasts. This indicates that the bones are no longer growing and cannot absorb the minerals present or adapt mechanically to changes in posture.
Biological system:
Respiratory system: Their cellular respiration is equivalent to ours, i.e. they need to oxidize organic components to produce energy. Their lungs have no reciprocating action, but rather have a unidirectional flow of air, similar to those seen in birds, which is more efficient than ours. It is speculated that this is in response to the brain's elevated metabolic needs. Vocalization is produced by vibration of the wall membrane at the junction between the two air sacs.
The Circulatory system of EBOs is rather analogous to ours. The heart is located in the mediastanum, but in a more medial position, directly beneath the sternum. The heart has two ventricles and two atria. There is an aorta, a pulmonary vein, a pulmonary artery and a vena cava. Blood flowing to the pulmonary capillaries via the pulmonary artery is pumped against the flow of air, maximizing gas exchange efficiency. The blood gas barrier is relatively narrow in these capillaries, at least compared to a human. Then oxygen-rich blood is returned to the heart and then expelled into the aorta and the rest of the body. Before returning to the heart, the blood will pass through the hepatorenal organ which, among other things, filters and controls osmotic pressure of the blood.
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