Respiratory System

Function Supply the blood with oxygen For the blood to deliver oxygen to all parts of the body Breathing Inhale oxygen; exhale carbon dioxide

The Pathway Air enters the nostrils Passes through the nasopharynx The oral pharynx Through the epiglottis Into the trachea Into the right & left bronchi Branches and rebranches Into Bronchioles Terminates in a cluster of Alveoli

Alveoli ~300 million alveoli in two adult lungs Provide surface area ~160 m2 ~ equal to the singles area of a tennis court; 80 times the area of your skin

Breathing Diaphragm Divides the body cavity into the abdominal cavity & thoracic cavity Pleural membranes Lines inner surface of thoracic cavity & outer surface of the lungs http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter1/animation__the_pleural_membranes.html

Pleural membrane Adheres to each other creating a natural elasticity secretes a small amount of fluid that lubricates each surface so that they slide past one another as the lungs expand and contract If air is introduced between the membranes, lungs collapse

Breathing Inspiration (inhale) External intercostals muscles contact Lifts ribs out and up Diaphragm contracts Draws downward Expiration (exhale) Processes are reversed & natural elasticity of lungs returns to normal volume At rest, we breath 15-18 times a minute; exchange ~500 ml of air

Breathing

Diseases of the Lungs Pneumonia Infection of the alveoli Caused by many kinds of bacteria and viruses Tissue fluids accumulate in the alveoli Reduces surface area

Diseases of the Lungs Asthma Constriction of the bronchi and bronchioles Difficult to breathe in and out Triggered by: Airborne irritants Chemical fumes, cigarette smoke Airborne particles allergies

Diseases of the Lungs Emphysema Alveoli break down Reduces gas exchange area Forces the heart to pump larger volumes of blood Can lead to heart failure

Diseases of the Lungs Chronic Bronchitis inflammation (or irritation) of the airways Main cause is cigarette smoking

Diseases of the Lungs Lung Cancer Most common cancer and cancer deaths Uncontrolled proliferation of cells Most common types involve the epithelial cells lining the bronchi and bronchioles