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