Summary: An overview of the human immune system, beginning with some basic anatomy of the lymphatic system, and proceeding through a discussion of the distinction between the innate and adaptive immune systems, the role of skin and mucus membranes in providing barriers to pathogen entry, the inflammatory response, an overview of the different types of leukocytes, and an initial foray into the workings of the complement system. Recommended pre-listening is Episode 10: The Cell.<br>
