Gas ExchangeLizzie 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.youtube.com/watch?v=Aw9OJLTlClQ&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/chapter24/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