(2)Anatomy and Physiology pt.2

• The Hierarchy of Complexity is about the complexity of the structure of a system. i.e. organisms, organ systems, organs, tissues, cells, organelles, and molecules.
• Molecules are composed of atoms. Organelles are composed of molecules. Cells are composed of organelles. Tissues are composed of cells. Organs are composed of tissues. Organ systems are composed of organs. Organisms are composed of organ systems.
• Reductionism: When large, complex systems can be understood by studying their simpler components. This is essential to scientific thinking.
• Holism: Meaning that the “emergent properties” of the whole organism cannot be predicted from the properties of the separate parts. Simply put it means that the whole is greater than the sum of its parts.
• Anatomical Variation: a structural variation/ difference that does not impair its function. Meaning that no two humans are exactly alike anatomically. e.g. Some individuals show situs inversus—left-rightreversal of organ placement, some individuals have an atypical number of certain organs (for example, kidneys), some individuals have an atypical number of vertebrae, & some individuals lack certain muscles.
• Anatomy books are known to show the most common organization of structures but it doesn't mean that people with different anatomies (anatomical variations) don't exist.
• Characteristics of Life include; organization, movement, cellular composition, responsiveness, metabolism, Homeostasis, Development, Reproduction, and Evolution of a population.
• • Organization: Living things exhibit a higher level of organization than nonliving things.• Cellular composition: Living matter is always compartmentalized into one or more cells.• Metabolism: The sum of all internal chemical changes: anabolism (synthesis) and catabolism (digestion).• Responsiveness: The ability to sense and react to stimuli (irritability or excitability).• Movement—of organism and/or of substances within the organism.
• Homeostasis: means maintaining relatively stable internal conditions.
• Development: means differentiation and growth.
• Reproduction: means producing copies of themselves; and passing genes to offspring.
• Evolution of a population: means the changes in genes.
• Physiological Variation includes; Sex, age, diet, weight, and physical activity.
• Failure to consider variation can lead to overmedication of the elderly or medicating women based on research done on men.
• Homeostasis: This is the ability to detect change, activate mechanisms that oppose it, and thereby maintain relatively stable internal conditions.
• Claude Bernard (1813–78): He noted fairly constant internal conditions despite changing external conditions (for example, temperature).
• Walter Cannon (1871–1945): He coined the term homeostasis.
• Negative feedback allows for dynamic equilibrium within a limited range around a set point. Simply put, the body senses a change and “negates” or reverses it.
• Loss of homeostatic control causes illness or death.