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Diffusion and the Molecules of Life
Levels of Hierarchy and Organization in Living Systems and Multi-cellular organisms
Molecules of Life
C-chain Component Main Functions
Anatomy and Physiology in the Hierarchy of LifeMolecules
Cells
Tissues
Organs/Structures
Organ Systems
Organisms
Environment
Levels of Organization within Human Body
Levels of Organization• Chemical Level (Organic Chemistry and Biochemistry
• Cellular Level (Intro. Or Cell Biology): organelles, genes, mitosis, meiosis
• Tissue Level (Histology): groups of cells with common function—classes of tissues, epithelia (covering), connective tissues (support, protection)
• Organ Level (Anatomy): how tissues combine to form structures in body—lungs, bones, blood vessels, etc.
• Organ System level (Physiology) How organs and structures work together to accomplish specific functions: e.g., circulatory system, nervous system, skeletal system, etc.
• Organism: Entire body working together (Ecology or physiology in environment)
The importance of Diffusion• Diffusion versus Osmosis (diffusion across a membrane)• Diffusion fast and effective across microscopic distance• Virtually all living processes involve diffusion and/or osmosis• Cell membranes control diffusion and allow for life chemical reactions
to take place• Diffusion lets tissues do job and permits organ systems to function• Examples:
– Oxygen in circulatory system– Food in digestive system– Calcium in muscular function– Nerve impulses
Cell membranes and Diffusion
Body Systems and Diffusion
Understand path through body of:• Food/Nutrients (glucose)• Oxygen• Carbon Dioxide• Nitrogen
Homeostasis“…the ability to maintain relatively constant internal conditions even though the outside world changes continuously…”
• Within cells• Within body
Feedback Mechanisms• Negative Feedback Examples
– home heating system– Glucose regulation in blood
• Positive Feedback Examples– Fire-Starting– Blood clotting
Web Links
• Cellular basis of physiology
• Diffusion/Osmosis animation
Next Time:
Overview of Body Systems