The lymphatic system performs important immune functions, and runs parallel to the blood circulatory system to provide a secondary circulation that transports excess interstitial fluid, proteins and metabolic waste products from the systemic tissues back into the blood. For centuries, it was thought that the central nervous system lacks a lymphatic drainage system and the […]
Altruism is a basic principle in many cultures and religions: do good deeds to other persons without expecting a reward or even if it is detrimental for you. However, it is not exclusive to human beings: ant workers abandon their own reproduction to serve the queen, vampires spit up part of the obtained blood to […]
The human brain continues its development postnatally. It is a long process that extends throughout, at least, the first two decades of life. Along these years, environmental factors influence brain functions and, not surprisingly because of its high plasticity, brain structure. Among the variables that may affect the cognitive development is the socioeconomic status. Three […]
True empathy is considered by most researchers to be an exclusive ability of primates, particularly humans and apes, the result of complex reasoning and abstract thought. However, empathy may be a phylogenetically continuous ability with particular types such as «emotional contagion» present in all classes of mammals. In fact, it has been shown that empathy […]
The term epigenetics refers to heritable changes in gene expression (active vs. inactive genes) that does not involve changes to the underlying DNA sequence. It results in change in phenotype without a change in genotype. An easily comprehensible example are identical twins: since they develop from a single fertilized egg, they have the same genome […]
Blindness is a world wide problem. As of 2012 there were 285 million visually impaired people in the world, of which 246 million had low vision and 39 million were blind. Most people with poor vision are in the developing world and are over the age of 50 years. One basic aspect for quality of […]
Sensations which seem to come from limbs that had been amputated are called «phantoms». Most limb amputees report awareness of a phantom limb, i.e., the perceived presence of the missing arm or leg. Phantom sensations may also occur after the removal of body parts other than the limbs, e.g. after amputation of the breast, extraction […]