The notion of the “biological individual” is crucial to studies of genetics, immunology, evolution,development, anatomy, and physiology. Each of these biological subdisciplines has a specific conception of individuality, which has historically provided conceptual contexts for integrating newly acquired data. During the past decade, nucleic acid analysis, especially genomic sequencing and high-throughput RNA techniques, has challenged each of these disciplinary definitions by finding significant interactions of animals and plants with symbiotic microorganisms that disrupt the boundaries that heretofore had characterized the biological individual. Animals cannot be considered individuals by anatomical or physiological criteria because a diversity of symbionts are both present and functional in completing metabolic pathways and serving other physiological functions. Similarly, these new studies have shown that animal development is incomplete without symbionts. Symbionts also constitute a second mode of genetic inheritance, providing selectable genetic variation for natural selection. The immune system also develops, in part, in dialogue with symbionts and thereby functions as a mechanism for integrating microbes into the animal-cell community. Recognizing the “holobiont”—the multicellular eukaryote plus its colonies of persistent symbionts—as a critically important unit of anatomy, development, physiology, immunology, and evolution opens up new investigative avenues and conceptually challenges the ways in which the biological subdisciplines have heretofore characterized living entities.
The Polyvagal Theory helps us understand how cues of risk and safety, which are continuously monitored by our nervous system, influence our physiological and behavioral states. The theory emphasizes that humans are on a quest to calm neural defense systems by detecting features of safety. This quest is initiated at birth when the infant needs for being soothed are dependent on the caregiver. The quest continues throughout the lifespan with needs for trusting friendships and loving partnerships to effectively co-regulate each other. The Polyvagal Theory proposes that through the process of evolution, social connectedness evolved as the primary biological imperative for mammals in their quest for survival. Functionally, social connectedness enabled proximity and co-regulation of physiological state between conspecifics starting with the mother-infant relationship and extending through the lifespan with other significant partners. The theory explains why feeling safe requires a unique set of cues to the nervous system that are not equivalent to physical safety or the removal of threat. The theory emphasizes the importance of safety cues emanating through reciprocal social interactions that dampen defense and how these cues can be distorted or optimized by environmental and bodily cues.
Stress is ubiquitous and on the rise. How we learn to manage it can have profound effects on our health and well being. This series explains how our bodies experience stress and demonstrates effective strategies to help you thrive in a fast-paced world. On this edition, Richard Harvey discusses strategies to reduce stress beyond medication. Series: “UCSF Mini Medical School for the Public” [3/2008] [Health and Medicine] [Show ID: 13720]
Selections from Science and Sanity represents Alfred Korzybski’s authorized abridgement of his magnum opus, Science and Sanity: An Introduction to Non-Aristotelian Systems and General Semantics. This second edition, published in response to the recent Korzybski revival, adds new introductory material and a revised index, providing an accessible introduction to Korzybski’s arguments concerning the need for a non-Aristotelian approach to knowledge, thought, perception, and language, to coincide with our non-Newtonian physics and non-Euclidean geometries, to Korzybski’s practical philosophy, applied psychology, pragmatics of human communication, and educational program. Selections from Science and Sanity serves as an excellent introduction to general semantics as a system intended to aid the individual’s adjustment to reality, enhance intellectual and creative activities, and alleviate the many social ills that have plagued humanity throughout our history.
Cannon is best known for his work on the “Fight or Flight” response. In 1915, he coined the term “fight or flight” to describe an animal’s response to threats in “Bodily Changes in Pain, Hunger, Fear and Rage: An Account of Recent Researches into the Function of Emotional Excitement.” He is also credited with being one of the first to understand the significance of “Homeostasis” in the self-regulation of each human being. He developed the concept of “Homeostasis” from the earlier idea of Claude Bernard of milieu interieur, and popularized it in his book “The Wisdom of the Body” in 1932. Cannon presented four tentative propositions to describe the general features of homeostasis:
Constancy in an open system, such as our bodies represent, requires mechanisms that act to maintain this constancy. Cannon based this proposition on insights into the ways by which steady states such as glucose concentrations, body temperature and acid-base balance were regulated.
Steady-state conditions require that any tendency toward change automatically meets with factors that resist change. An increase in blood sugar results in thirst as the body attempts to dilute the concentration of sugar in the extracellular fluid.
The regulating system that determines the homeostatic state consists of a number of cooperating mechanisms acting simultaneously or successively. Blood sugar is regulated by insulin and other hormones that control its release from the liver or its uptake by the tissues.
Homeostasis does not occur by chance, but is the result of organized self-government.