Background and objective: Healthy stomatognathic system is a guarantee for nutrient intake of astronauts during long-term spaceflight, but few researches have been carried out to investigate the influence of weightlessness on oral health. This study was aimed to explore the effects of simulated weightlessness on the histology and immune status of gingival tissues of rhesus macaques using a 6w g...

In aerospace medicine, attention focuses on the effects of the loss of gravitational pull on the body. The more fundamental question involved is the basic physiology of anti-gravity mechanisms upon the body. From this viewpoint, the entire spectrum of the consequences of weightlessness may be seen. Then evidence affirming the broad concept of sensory deprivation in general, and anti-gravity dep...

Research into the effects of weightlessness on rat vestibular maculae has consistently shown that ribbon synapses in hair cells of the utricular maculae exhibit statistically significant changes in number, kind, and distribution when rats are exposed to space flight (Ross, 1993, 1994, 2000). Synaptic plasticity was most evident when all type II hair cells of these maculae were considered and wa...

Exposure to weightlessness affects the control and appreciation of body position and orientation. In free fall the perception of one's own orientation and that of the surroundings is dependent on the presence or absence of contact cues, whether part of the body is visible in relation to the architecturally defined verticals of the space craft, cognitive factors, and exposure history. Sensations...

This paper reviews the interventions to stabilize calcium balance and bone metabolism and prevent bone loss in astronauts during space flight. Weightlessness during space flight results in calcium, vitamin D, and vitamin K deficiency, increases urinary calcium excretion, decreases intestinal calcium absorption, and increases serum calcium level, with decreased levels of serum parathyroid hormon...

The endocannabinoid system (ECS) plays an important role in the regulation of physiological functions,from stress and memory regulation to vegetative control and immunity. The ECS is considered a central and peripheral stress response system to emotional or physical challenges and acts through endocannabinoids (ECs), which bind to .their receptors inducing subsequent effecting mechanisms. In ou...

Acoustic levitation and diamagnetic are experimental methods that enable the contact-free study of both liquid droplets solid particles. Here, we combine techniques into a single system takes advantage strengths each, allowing for manipulation levitated spherical water (30 nl–14 μl) under conditions akin to weightlessness, in laboratory, using superconducting magnet fitted with two low-power ul...

To determine when choroidal structures were restored after readaptation to Earth gravity or orthostatic position, fine structure and protein distribution were studied in rat choroid plexus dissected either 6 h [Space Life Sciences-2 (SLS-2) experiments] or 2 days [National Institutes of Health-Rodent 1 (NIH-R1) experiments] after a spaceflight, or 6 h after head-down tilt (HDT) experiments. Api...

Prolonged weightlessness results in a weakening of the heart, a loss of skeletal muscle strength and volume, and decreased bone density. At this time, the only effective treatment for these problems is in-flight exercise. The basic unit of exercise is a single twitch contraction of one Òmotor unitÓ. If spinal cord excitability (SCE) is reduced during space flight, this would hinder motor unit r...