![[Microbiota.png|400]] > See also: > - [[Microbiology]] # The Human Microbiome **The human microbiome** is best described as *all the microbes that reside in and on a human body*. This even includes microbes that can be considered “non-essential” or are not actively-metabolizing. *Babies remain “sterile”* within the mother during pregnancy and the development of their microbiota does not begin *until they are birthed*. - Typically a stable community of microbes forms *by the age of three*. A **functional core microbiome** includes microbial genes that provide the host with a suite of activities required for health and homeostasis ## Types of Microbes **Commensal microorganisms** habitually live on or inside of the human body and do not cause disease or harm, sometimes even benefiting the host. A [[Pathogens|pathogen]] is any organism (typically microorganism) with the potential to cause disease. --- The community of microbial species that inhabits the human body is called the **microbiota**, such as: - Gut Microbiota - Oral Microbiota ### Self vs Non-Self (Pathogens) An organism is called a [[Pathogens|pathogen]] if it has the potential to cause disease/harm the host organism. On the other hand, the term "**self**" is often used within immunology to describe civilian cells or ## Role of Microbes on Host Homeostasis Colonization resistance is the idea that the microbiota in the gut is protected from disease by the presence of a healthy community Probiotic refers to live microorganisms, which when administered in adequate amounts, confer a health benefit to the host. ### Diseases Associated With Changes in Microbiota **Dysbiosis** is a change in the microbiota that alters homeostasis within the host, possibly to the point of causing disease. - Ex: Metabolic endotoxemia