Studies on immune responses in afferent and efferent lymph of lymph nodes draining the tissues have contributed to the concept that primary immune responses are generated in the lymph nodes with a delay before antigen-specific effector cells arrive at the affected tissue.
Lightning strikes the ground approximately 25 million times each year in the U.S. According to the NWS, the chance of an individual in the U.S. being killed or injured during a given year is one in 240,000. Assuming an average life-span of 80 years, a person's odds over their lifetime becomes one in 3000.
(Reuters) In the first half of the 20th century, hundreds of Americans died each year from lightning strikes. The data is messy, but in the years from about 1920 to the middle of the 1940s, about 400 people were killed by lightning annually. Last year, 23 did, the fewest on record.