Cortical neurons (nerve cells) growing in culture. Neurons have a large cell body with several long processes extending from it, usually one thick axon (red) and several thinner dendrites. The axon carries nerve impulses away from the neuron. Its branching ends make contacts with other neurons and with muscles or glands. The highly branching dendrites receive information from other neurons. This complex network forms the nervous system, which relays information rapidly through the body.
Mold (Aspergillus versicolor). Conidia (asexual spores) are produced on the conidiophores (fruiting structures / sporangia). Aspergillus versicolor is very common in damp places including: gypsum boards, carpets, mattresses, upholstered-furniture and damp walls. It is commonly found in soil, hay, cotton, and dairy products. It can produce a mycotoxin, sterigmatocystin, and cyclopiaxonic acid. Sterigmatocystin is reported to be carcinogenic to the liver and kidney, and it can cause such symptoms as diarrhea and upset stomach. This genus can also cause skin infections in burn victims and the fungal lung infection aspergillosis (secondary infection to AIDS).
Dust mites (Dermatophagoides spp.) on cotton fabric
Photocomposite of dust mites (Dermatophagoides spp.) on cotton fabric (bed sheet). Millions of dust mites inhabit the home, feeding on dead scales of human skin that are common in house dust. The average double bed contains about two million dust mites of various species. The mite's body is in three parts: the gnathosoma (head region) adapted for feeding on dead skin, the propodosma (carrying the 1st & 2nd pair of walking legs) and the hysterosoma (locating the 3rd & 4th pairs of legs). Dust mites produce 10-20 waste particles per day. The dead bodies and fecal pellets can trigger allergic responses. The whole life cycle from egg to adult takes approximately one month to complete, mature female mites can lay from 1-2 eggs per day. Adult mites can live up to two months but this is dependent on the levels of humidity and temperature of their surrounding environment.