Read Secrets of Your Cells: Discovering Your Body's Inner Intelligence for Free Online

your religious and spiritual inclinations and practices. And if they fit into your belief system, you have an astrological sun sign, a tarot symbol, and perhaps a lucky number. All of these are, or can be, parts of your identity, as are your beliefs and actions.
    How do you recognize yourself? Is it by what you do in the world? By how people know and react to you? Is your sense of self externally or internally motivated? These are questions to contemplate as you begin to examine the parallels between your own sense of self and the self-identity of the cell. Knowing the self is like cultivating a garden: youhave to be willing to explore the invisible and slow down to nurture your awareness. You need to be willing to work deeper than the surface. For your cells, however, the surface is the key to identity.
    “Who am I?” is a question that can be answered by both our cells and our psyches, which together engage in an ongoing conversation to keep us safe. Body and mind share a common responsibility in self-identity, safeguarding us from danger and knowing what to trust. Both detect and protect our boundaries; the body’s immune system, a scientific focus of this chapter on recognizing self and other, determines cellular boundaries and identities, while the nervous system navigates psychological ones.

    DEFINITION
    Immune, from the Latin immunis: Exempt from public service or charge. Protected. Resistant to a particular infection or toxin owing to the presence of specific antibodies or sensitized white blood cells or relating to the creation of resistance to disease.

    The basic job of our immune cells is to recognize “self” and “other” while collaborating with brain, gut, thoughts, beliefs, and hormones. The immune cells are sometimes referred to as a second sensory system, one that sniffs out danger. It is essential to add here that while our genes provide the information for crafting the physical and chemical aspects of our unique identity, our cells reveal those characteristics and our immune cells act on them.
    Before we explore the specific activities of immune cells in some depth, let’s take a closer look at cell identity (see figures 2.1 and 2.2 ).
    How Our Cells Say, “I AM”
    In the architectural design of our cells, the wonderful, fluid exterior membrane that we encountered in the last chapter reveals the cell’s identity. Just as you and I can tell a friend from a stranger by observing a person’s external facial features, our cells do the same; each cell’s “face,” on its outer surface membrane, reveals uniquely identifiable features. Our cellular container is embedded with markings that enable cells to discern one from another. Blips and bumps on the surface are identification codes or passwords that mark “me” or self. These protein “signatures” on the cell membrane, akin to distinctive bar codes, reveal the cell’s identity. These “me” markers also identify the cells as coming from you, a unique individual.

    Figure 2.1 Cell as self, “me”

    Figure 2.2 Cell as other, “not me”
    Like us, each cell has several layers of identity. In addition to “self” markings on the outer edges, cells carry “postmarks” or “zip codes” indicating where the cell originated and what it does: heart cells pump blood; white blood cells protect against intruders; red blood cells carry oxygen to all the tissues, and so on.
    Recognizing Self and Other
    When cells touch, their identification markings enable them to distinguish “self” from “other.” A reading of “other,” or not self, can signal either safety or danger: a threat that must be defended against. In thebigger picture of survival, “other” may be a threat if it is a pathogenic microorganism. Though it is well established that physical markings, shape, and touch are essential in enabling cells to recognize other cells and molecules, some scientists are now theorizing that molecular vibrations also play a part in