Genome Complexity; amazing immune system (Introduction)

by David Turell , Thursday, January 28, 2016, 14:16 (3223 days ago) @ David Turell

We get some initial immunity from mother's milk at the start of life and then we build up our own antibodies which can last a lifetime, because there are dangerous bugs everywhere all the time:-http://www.evolutionnews.org/2016/01/the_immune_syst_1102547.html-"Rather than having eyes to see with and ears to hear, the cells of the body interact with chemicals and other cells, both foreign and domestic, through the plasma membrane. The surface of the plasma membrane contains thousands of different molecules that relate to its structure and function. Moreover, to detect a specific set of chemicals on the surface of another cell the plasma membrane must have a specific receptor. These receptors consist of protein molecules that contain a specific grouping of chemicals, resulting in a specific, three-dimensional shape that allows them to chemically bind, like Velcro, to the molecule being detected. -"Pathogenic (disease causing) microbes have specific chemicals on their surface that relate to their structure and function, called pathogen-associated molecular patterns (PAMPs). The first responder cells of the innate immune system have specific molecular structures on the plasma membrane that are able to detect these PAMPs, called pattern-recognition receptors (PRRs). It is estimated that the immune cells of the innate system can identify about one thousand different PAMPs. Since these PAMPs only occur on microbes and not on human cells, these specific receptors (PRRs) allow the cells of the innate immune system to identify invading microorganisms as foreign and the ones to be destroyed. -"As noted previously, when target cells, like the ones lining the tubules in the kidney or the muscles surrounding the arterioles, lock on to a specific hormone or neurohormone, this triggers some action. Similarly, when the first responder immune cells of the innate system use their specific receptors (PRRs) to lock on to the specific chemicals on the surface of the invading microbes (PAMPs), they activate. This activation triggers them to identify the enemy, sound the alarm to bring more defenders to the battle, provide strategic information about the invading force, and repel, incapacitate, or kill the intruders. Here's the starting line-up and how they do it.-***-"When mast cells' specific receptors attach to the specific chemicals of an invading microbe, this activates them to release their granules into the surrounding tissue. The granules contain many chemically active molecules, one of which is histamine. -***-"Macrophages (large eaters) are immune cells that are located in all of the tissues and organs of the body. Like mast cells, they activate when their specific receptors attach to specific chemicals on foreign microbes. This triggers them to engulf and literally swallow up the invader. Then, by using specific enzymes, they chemically digest and kill them in a process called phagocytosis (phagein is Greek for "to eat"). -***-" The main job of activated dendritic cells, once their specific receptors have attached to specific chemicals on the surface of the microbe, is to kill it by phagocytosis and process some of its chemicals to provide important information to the cells of the adaptive immune system. Activated dendritic cells also release cytokines that help to improve and regulate the immune response to foreign microbial invasion."-Comment: And this complexity came from chance! Hah!