Announcements Have your “I am a _________ cell” information ready. Knowledge survey on-line: check for link Personal info (voluntary) due Friday Group pictures in lab this week Community of Scholars Research Symposium –Saturday Sept 12 –10 wks paid research on topic of your choosing! –Summer 2010

The body: A society of interdependent cells, each type with its own needs and contributions.

The Human Body: A Society of Cells Imagine you are a cell. Ask yourself: How did I get here? What do I do for myself? (What are my special characteristics and functions?) What do I do for the person in whom I reside? (What are my contributions to the whole organism? To homeostasis?) What do I need simply to survive? What do the other cells provide for me that I cannot obtain alone? What governs my actions? How long will I live? Can I be replaced? If so, how? What would happen to the organism if I along with all the other cells of my type were to fail to function properly?

O2O2 pH CO 2 Temp, [glucose], [Na+], [K+], [Ca++], amino acids Nucleic acids

Cell Membrane: selectively permeable Capillaries: highly permeable except to proteins

Homeostasis: The relative constancy of the internal environment Steady state vs. equilibrium Beggar Thessaloniki, Greece

Homeostasis: The relative constancy of the internal environment Steady state vs. equilibrium Street vendor Thessaloniki, Greece

Homeostasis: The relative constancy of the internal environment Steady state vs. equilibrium San woman Kalahari Desert, Botswana

Homeostasis: Camp’s Bay Beach, Cape Town, South Africa

Homeostasis: Phillip cooling off in waterfall, Vietnam

~37 o C

Homeostasis Regulated via reflex arcs and naturally maintained by the process of negative feedback Measurement –Which physiological variables? –Averages and ranges

Fig Awake Sleep Diurnal cycles

Thermoregulation

The Challenge: # 1: Melt these 6 ice cubes as fast as possible. How to do it? # 2: Make these 6 ice cubes last as long as possible? How to do it? These are non-living objects: heat exchanges with the environment but they don’t generate heat from metabolism as living things do!

Conduction Convection Evaporation Radiation Metabolism generate heat, metabolism is variable! ~37 o C

Modes of Heat Exchange: Conduction Convection Radiation Evaporation ~37 o C

Modes of Heat Exchange: Conduction Convection Radiation Evaporation ~37 o C

Modes of Heat Exchange: Conduction Convection Radiation Evaporation ~37 o C