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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

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Overview of Body Systems