RESPIRATORY SYSTEMS

DIFFUSION Diffusion is the movement of molecules from areas of high concentration to areas of lower concentration WHAT SPEEDS UP DIFFUSION? Heat Increased surface area Higher concentration gradients

WHY DO ORGANISMS NEED OXYGEN? Glucose is the body’s fuel ATP is the cells fuel Oxygen helps break glucose down into ATP. This occurs in the ________ MITOCHONDRIA

Plants take in CO 2 and H 2 O and Make Sugar and Oxygen We take in Sugar and Oxygen and make CO 2 and H 2 O (and ATP from the glucose)

FISH

Countercurrent flow WATER IS NOT VERY HIGH IN OXYGEN Water flows in one direction. It has a higher content of oxygen than the fish. The blood stream, which flows in the opposite direction, has a lower concentration of oxygen Increased concentration gradient = increased diffusion Fish absorb more than 80% of the dissolved O2 from water into their blood.

SIMPLE DIFFUSION…FLAT WORM, EARTHWORM, AND GRASSHOPPER GASSES DIFFUSES STRAIGHT THROUGH THE SKIN AND INTO THE CELLS

Gases must be dissolved before they can diffuse. GASSES DIFFUSE STRAIGHT THROUGH THE SKIN AND INTO BLOOD STREAM WHICH IS PUMPED THROUGHOUT THE BODY

GASSES ENTER AND LEAVE THROUGH SPIRACLES

Land animals are constantly battling water loss (there’s more H 2 O in us than the outside of us)…so we have small openings to the outside world.

Site with animation showing exchange of gases in lung

NASAL PASSAGES… WARM THE AIR (INCREASES DIFFUSION) MOISTENS THE AIR (GASSES MUST BE DISSOLVED BEFORE THEY CAN DIFFUSE INTO US) FILTER (WE DON’T WANT TO CLOG OUR ALVEOLI)

We are not very efficient at gas exchange because the oxygen rich blood and the oxygen poor blood come in close contact in the lungs…so not a high concentration gradient WE HAVE A 2WAY PATHWAY

ONE WAY SYSTEM AND VERY EFFICIENT. BIRDS NEED A LOT OF ATP FOR FLYING

WATER FILLS THE GUARD CELLS TO CREATE AN OPENING TO THE STOMATA. DROUGHT = LOW WATER SO STOMATES NOT OPEN (GUARD CELLS CLOSED)