MICR 2123 Lecture 16: Chapter 23
5 Nov 2016
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Document Summary
There exists a lot of microorganisms in and on our human body: most are harmless if they stay where they belong, some are even beneficial to their host. The human body is also under constant attack from microbial invaders: fortunately, we have barriers: For those that are successful in invading, we have adaptive and non- adaptive immune defenses. Our bodies carry 10x as many microbial cells as human cells: bacteria normally found at various non-sterile body sites are called commensal organisms. The consortium of colonizing microbes has been dubbed the human microbiota or microbiome. Microbe populations can cause disease if they reach abnormal location. Mostly gram-positive bacteria: skin is subject to dryness (with the exception of certain areas like the scalp and armpits). Also, epidermal secretions are salty: gram-positive bacteria are more resistant to salt and dryness. All colonizers here need to be able to adhere to surfaces to avoid flushing to the acidic stomach, e. g. glycocalyx.
