Mechanism of anoxic depolarization in the brain disruption. Other consequential damage that occurs includes lipolysis, proteolysis, cell swelling, microtubule disaggregation, and DNA fragmentation. Neurons are more susceptible to brain ischemia than the supporting glial cells, because neurons have higher energy demand, conduct an action potential, and produce glutamate, whereas glial cells lack those properties. Yet neurons differ among themselves in their sensitivity to ischemia, depending on the specific properties they exhibit, relating to their locations in the brain. "Selective vulnerability" is the term used to describe how some parts of the brain are more sensitive to anoxia than others, and thus to ischemic insult. Anoxia-prone cells in
Composition of the human body viewed on an atomic and molecular scale as shown in this article. The estimated gross molecular contents of a typical 20-micrometre human cell is as follows: Body composition can also be expressed in terms of various types of material, such as: There are many species of bacteria and other microorganisms that live on or inside the healthy human body. In fact, 90% of the cells in (or on) a human body are microbes, by number (much less by mass or volume). Some of these symbionts are necessary for our health. Those that neither help nor harm humans are called commensal