Gas Exchange Lizzie Cymanski

Functions Acquisition of oxygen Distribution of gases Removal of carbon dioxide

Importance Oxygen is needed for cellular respiration The body needs to get rid of carbon dioxide, the product of cellular respiration

Cellular Respiration vs. Respiration Cellular Respiration -- the use of oxygen and production of carbon dioxide at a cellular level also called internal respiration Respiration -- the uptake of oxygen from the environment and the disposal of carbon dioxide at the body system level also called external respiration

Respiratory system needs: large respiratory surface (lungs, gills) a method for ventilating respiratory surface a pump and circulatory system to distribute gases

Bacteria In bacteria and other very small organisms, cells are in always in contact with the environment Gas exchange happens easily

Respiratory Surfaces The first respiratory surface was skin doesn’t work for larger animals Most amphibians still use skin for 100% of their gas exchange Fish, reptiles, humans get some respiratory gases from skin

Evolution As animals grew larger, their body’s surface area wasn’t large enough for gas exchange through skin Aquatic animals developed gills, terrestrial animals developed lungs

Lungs Humans have two lungs -- the left divided into two lobes, the right, three Two zones -- the conducting zone and the respiratory zone Protected by the rib cage

Conducting Zone Trachea -- connects the pharynx to the lungs, allows the passage of air Trachea divides into two bronchi which divides into bronchioles which divides into terminal bronchioles No gas exchange with blood Warms, cleans and humidifies air Reinforced with cartilage to keep airways open

Respiratory Zone alveolar ducts -- the tiny ends of the airways alveoli -- form at the end of alveolar ducts, sac-like structures, site of gas exchange www.youtube.comhttp://www.y outube.com/watch?v=Aw9OJL TlClQ&feature=fvst

Pleural Cavity Lungs covered in visceral pleural membrane Lungs lined in parietal pleural membrane The pleural cavity is the space between the two membranes The cavity is filled with water to hold the two membranes together

Interesting Facts The lungs: contain 1500 miles of airways 300 to 500 million alveoli total surface area of 70 sq. miles -- about the size of one side of a tennis court If all the capillaries were unwound, they would be 620 miles long

Circulatory System The circulatory delivers the oxygen to cells all over the body and then carries away carbon dioxide Most oxygen is bound to molecules of hemoglobin inside red blood cells

Hemoglobin A protein made of four polypeptide bonds and four organic compounds called heme groups At the center of each heme group is an atom of iron The iron molecule can bond to a molecule of oxygen Each hemoglobin can carry four oxygens

(De)Oxyhemoglobin Oxyhemoglobin – hemoglobin that is full of oxygen, a bright red color Deoxyhemoglobin – hemoglobin that has released its oxygen, a dark red that appears blue under tissue

History of Hemoglobin Hemoglobin is an ancient protein Not only used in vertebrates but also in annelids, mollusks, echinoderms, flatworms, and even some protists Other invertebrates use hemocyanin which has a base of copper instead of iron

Emphysema One of the main forms of Chronic Obstructive Pulmonary Disease (COPD) The destruction of the lungs over a long period of time Most common cause is smoking, also caused by exposure to pollution Cannot be cured but can be treated

Emphysema Symptoms Cough with mucus Shortness of breath Fatigue Wheezing Frequent respiratory infections

Tuberculosis Caused by the bacteria Mycobacterium tuberculosis Very contagious Can be cured but takes very long time If not treated properly, spreads to other organs

TB Symptoms Cough Coughing up blood Excessive Sweating Fatigue Fever Weight loss

Cystic Fibrosis Inherited disease Causes thick, sticky mucus to build up in lungs and digestive tract May also affect sweat glands and male reproductive system Most commonly affects Caucasians Only live to mid-30’s

Cystic Fibrosis Symptoms Salty-tasting skin Frequent lung infections Wheezing and shortness of breath Delayed growth Problems with bowel movement

http://cwx.prenhall.com/bookbind/pubbooks/martini10/c hapter24/custom2/deluxe-content.html http://www.ncbi.nlm.nih.gov/pubmedhealth/ http://www.google.com/images http://health.howstuffworks.com/human- body/systems/respiratory/lung.htm http://icb.oxfordjournals.org/content/28/2/739.abstract