Cockroach Even after having its head cut off, a cockroach can still live for weeks. To understand why cockroaches -and many other insects- can survive decapitation, it helps to understand why humans cannot, explains physiologist and biochemist Joseph Kunkel at the University of Massachusetts Amherst, who studies cockroach development. First off, decapitation in humans results in blood loss and a drop in blood pressure, hampering oxygen and nutrition transport to vital tissues. In addition, humans breathe through their mouth or nose, and the brain controls that critical function so that breathing stops. Moreover, the human body cannot eat without the head, ensuring a swift death from starvation should it survive the other ill effects of head loss. But cockroaches do not have blood pressure the way people do. "They don't have a huge network of blood vessels like humans or tiny capillaries that you need a lot of pressure to flow blood through," Kunkel says. "They have an open circulatory system, which there's much less pressure in. After you cut their heads off, their necks would often seal off just by clotting," he adds. Cockroaches are also poikilotherms, or cold-blooded, meaning they need much less food than humans do. "An insect can survive for weeks on a meal they had one day," Kunkel says. "As long as some predator doesn't eat them, they'll just stay quiet and sit around unless they get infected by mold, bacteria, or a virus. Then they're dead." Source: Ultimate Facts 🖼️@https://www.pestworldforkids.org/pest-guide/cockroaches/

SPIDER BLOOD Spiders have transparent blood. The spiders have circulating blood in their bodies. The colorless blood, called hemolymph, transports nutrients, hormones, oxygen, and cells. The blood also serves another purpose. It is used locally to raise blood pressure during molting (shedding old skin) and stretch the legs. In mammals, hemoglobin molecules present in the red blood cells transport oxygen. The spider uses a more complicated protein called hemocyanin. Unlike hemoglobin, hemocyanin is not stored in a cell but flows freely in the blood of a spider. Hemocyanin is a protein comprised of 24 subunits with a molecular mass of 1.704.000 compared to the molecular mass of oxygen, which is only 32. Human hemoglobin comprises four subunits with a molecular mass of 64.500. Hemoglobin is a molecular disc made of nitrogen, carbon, hydrogen, and an iron atom at the center. The oxidized iron gives the molecule its characteristic red color. Haemocyanin also contains nitrogen, carbon, and hydrogen but has a copper atom at the center instead of an iron atom. The oxidized copper gives the molecule a blue color. Hemocyanin binds oxygen but only releases it after it receives the right chemical signal. For each of the 24 sub-units, there is a special chemical signal. A cell can give more or fewer signals depending on the need for oxygen. Besides these signals, the release of oxygen is also controlled by temperature. Every sub-unit has a specific temperature optimum. Source: The Ultimate Facts App Photo Source: National Geographic