13: The Human Microbiota
- Page ID
- 42551
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Chapter 13 BIOL 235 Learning Outcomes
- Identify the locations and some major genera/groups of normal microbial flora, specifically: enterobacteriaceae (such as E. coli), Bacteroides, Staphylococcus (genus), Staphylococcus aureus, Micrococcus, Candida, Streptococcus, Neisseria, Haemophilus.
- Describe all the sites that normally harbor microbial flora as "internal" or "external".
- Describe how normal flora is initially acquired.
- Explain the major roles of normal microbial flora and provide examples of ways in which normal flora impact nutrition, behavior, immune health, and organ development.
- List three ways normal flora protects from infection.
- Briefly describe the roles of short chain fatty acids (SCFAs) and serotonin in the "dialog" between the microbiota and human body.
- Describe two mechanisms by which the activity of gut microbiota can impact human metabolic physiology (available calories, blood sugar, blood lipids).
- Explain at least one way that diet can affect the activity of the gut microbiome.
- Distinguish between probiotic and prebiotic.
- Compare and contrast: primary and opportunistic pathogens, endogenous and exogenous infections.
- Explain how the normal flora can act as a source of pathogens and be able to provide examples.
- Explain why use of broad-spectrum antibiotics can lead to superinfections.
- 13.1: Normal Flora of the Human Body
- This page discusses the human microbiota and its importance in health, highlighting the roughly 1:1 ratio of bacterial to human cells. While bacteria represent fewer cells than human genetics, their genetic diversity and physiological roles are significant. The normal flora aids in system development, immunity, and nutrient absorption, with diversity differing by body area. The microbiome is established at birth and influenced by diet and environment, affecting long-term health.
- 13.2: The Role of Microbiota in Human Physiology
- This page highlights the crucial role of the human microbiota, particularly gut bacteria, in health and physiology, akin to a "virtual organ." It emphasizes the production of short-chain fatty acids (SCFAs) that aid in metabolism and protect against diseases like diabetes and cardiovascular issues.
- 13.3: Pathogens in the Normal Flora
- This page discusses normal flora, highlighting its role as beneficial microbes and potential harboring of opportunistic pathogens like E. coli and viridans Streptococci, which can cause infections under compromised host defenses. It notes that infections may arise from conditions such as impaired immunity or disrupted flora, with specific mention of Candida and C. difficile.
- 13.4: Probiotics and Prebiotics
- This page discusses probiotics, beneficial microbes that support health, especially for the young and elderly, by preventing issues like antibiotic-associated diarrhea and improving immune-related conditions. It also covers prebiotics, substances that nourish gut bacteria, primarily found in high-fiber foods. Additionally, it emphasizes the significant role of diet in influencing gut microbiota composition and overall health.
Thumbnail: "Beneficial Gut Bacteria" by National Institutes of Health (NIH) is licensed under CC BY-NC 2.0