Any of numerous hormone-like, low-molecular-weight proteins, chemically identified as purines, secreted by various cell types that regulate the intensity and duration of immune response and mediate cell-cell communication, as well as acting as signals in cell survival, growth, differentiation and apoptosis. Examples include interferon, interleukin, lymphokine, chemokines and various growth factors. See Apoptosis (or cell …
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Cytoplasm
The jelly-like material (protoplasm) surrounding the nucleus of a cell containing fibrous elements consisting of the Golgi apparatus, microtubules, actin microfilament, and intermediate filaments. It serves three main functions: energy, storage, and manufacturing, as well as containing RNA through which proteins are synthesized. These self-propagating entities can be inherited in a non-Mendelian mode (cytoplasmic inheritance). …
Cytoarchitectonic independence
Refers to the anatomical and cellular orthogonality of different brain regions. See Cortical area, Modularity
Cytochrome c oxidase (CCO)
Terminal enzymeof the mitochondrial respiratory chain and catalyzes over 95% of oxygenmetabolism. CCO has an absorption peak in the middle of the near infraredregion, and it can therefore be measured using NIRS and used as a non-invasivemarker of changes in mitochondrial oxygen consumption and utilization (ratherthan hemoglobin that is only going to tell us about …
Cybernetics
Although a term first used in French (‘cybernetique’) by André M. Amperé (1775-1836), it is generally credited to Norman Weiner (1894-1964) who derived it in 1947 from the Greek word for ‘steersman’ to denote the study of communication, feedback, and control mechanisms in living systems and machines. Subsequently developed together with Arturo Rosenblueth (1900-1950), Julian Bigelow (1913-2003) …
Cumulative incidence (CI)
The proportion of people who become diseased during a specified period of time and calculated as: CI = number of new cases of a disease during a given period of time / total population at risk An even more precise estimate of incidence that utilizies all available information is the incidence rate (IR), force of …
Cushing’s disease
See Addison’s disease, Adrenal glands
Culture
Partially overlapping systems of artefacts (e.g., social institutions, technology), meanings, practices and symbols (e.g., derived from myths) that are distributed throughout a given linguistic community, and which guide the shared life of individuals in different groups. Language and sign systems play a central role in representing the meanings that are distributed throughout a culture. See …
Cultural evolution and biological evolution
The theoretical stance adopted in sociobiology and its successor evolutionary psychology that biological and cultural evolution co-evolve, a sort of Darwinian theory of culture, and termed a ‘feedback reciprocal relation’ by Theodosius Dobzhansky (1900-1975). Accordingly, there is a direct co-evolutionary relationship between genes and culture such that changes in one can lead to changes in …
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Cultural selection
The claim that culturally-determined selection pressures can act on human gene frequencies to create biological changes. Two examples offered are lactose tolerance and the ability to metabolise alcohol, both seemingly having arisen rapidly and recently to create divergent evolution in humans. Such downward causation has been challenged by those who prefer to interpret these examples …