 Includes the tubes that remove the particles from incoming air  Transport air to and from the lungs  Respiration: gas exchange between body cells and atmosphere  air sacs

 Upper respiratory tract: nose, nasal cavity, paranasal sinuses, and pharynx  Lower respiratory tract: larynx, trachea, bronchial tree, and lungs

 Nose: bone and cartilage for support  Nostrils: openings for air  Nasal Cavity  Nasal conchae: divides cavity into passageways Helps increase the surface area of mucous membranes  Mucous Membrane filters, warms, and moistens incoming air  Ciliary action carries particle trapped in mucus to the pharynx, where they are swallowed

 Paranasal Sinuses  Spaces in the bones of the skull that open into the nasal cavity  Lined with mucous membranes  Pharynx: behind the oral cavity and between the nasal cavity and larynx  Passageway for air and food

 Larynx: conducts air and helps prevent foreign objects from entering the trachea  Composed of muscles and cartilages  Lined with mucous membranes  Contains vocal cords Vibrate from side to side to produce sound with air passes  Glottis and epiglottis help prevent foods and liquids from entering the trachea

 Trachea: extends into the thoracic cavity in front of the esophagus  Divides into the right and left bronchi  Bronchial Tree  Consists of branched air passages  Lead form the trachea to air sacs  Alveoli: at the distal end of the narrowest tubes Alveolar ducts

 Lungs  Separated by the mediastinum  Enclosed by diaphragm and thoracic cage  Visceral Pleura: attaches to the surface of the lungs  Parietal Pleura lines the thoracic cavity  Each lobe is composed of alveoli, blood vessels, and supporting tissue

 In 20 minutes your blood pressure will drop back down to normal.  In 8 hours the carbon monoxide (a toxic gas) levels in your blood stream will drop by half, and oxygen levels will return to normal.  In 48 hours your chance of having a heart attack will have decreased. All nicotine will have left your body. Your sense of taste and smell will return to a normal level.  In 72 hours your bronchial tubes will relax, and your energy levels will increase.  In 2 weeks your circulation will increase, and it will continue to improve for the next 10 weeks.  In three to nine months coughs, wheezing and breathing problems will dissipate as your lung capacity improves by 10%.  In 1 year your risk of having a heart attack will have dropped by half.  In 5 years your risk of having a stroke returns to that of a non-smoker.  In 10 years your risk of lung cancer will have returned to that of a non- smoker.  In 15 years your risk of heart attack will have returned to that of a non- smoker.  credit - HealthboltHealthbolt

 Changes in size of the thoracic cavity accompany inspiration and expiration

 Atmospheric pressure forces air into the lungs  Occurs when the pressure inside the alveoli decreases  Diaphragm moves downward  Thoracic cage moves upward and out  Surface tension aids in lung expansion

 Elastic recoil of tissues and surface tension within alveoli provide the forces of expiration  Thoracic and abdominal wall muscles aid expiration

 Respiratory cycle: one inspiration followed by one expiration  Tidal Volume: amount of air that moves in/out during a single respiratory cycle  Inspiration Reserve Volume: additional air that can be inhaled  Expiratory Reserve Volume: additional air that can be exhaled

 Residual Volume: air remaining in the lungs after a maximal expiration  Vital Capacity: maximum amount of air a person can exhale after taking the deepest breath possible

 Inspiratory Capacity: maximum volume of air a person can inhale following exhalation of the tidal volume  Functional residual capacity: volume of air that remains in the lungs after a person exhale the tidal volume  Total Lung Capacity: vital capacity + residual volume

 Normal breathing is rhythmic and involuntary  Respiratory center: brain stem, pons, and medulla oblongata  Medullary rhythmicity area: two neuron groups  Dorsal respiratory group: basic breathing rhythm  Ventral respiratory group: increases inspiratory and expiratory movements during forceful breathing  Pneumotaxic area: regulates breathing rate

 Chemicals, stretching of the lung tissue, and emotional states  Chemosensitive area:  Blood concentrations of CO 2 and H + influence chemoreceptors  Stimulation of these receptors increases breathing rate  Peripheral chemoreceptors: located in the walls of certain large arteries  Sense low oxygen concentration  Increases breathing rate

 Overstretching lung tissue triggers an inflation reflex  Shortens the duration of inspiratory movements  Inflation reflex prevents over-inflation of the lungs during forceful breathing  Hyperventilation: decreases blood CO 2  Very dangerous when done before swimming

 Gas exchange occurs in the alveoli  Alveoli: tiny air sacs clustered at the distal ends of alveolar ducts  Respiratory membrane: consists of alveolar and capillary walls  Blood and alveolar air exchange gases across membrane

 Diffusion across the respiratory membrane  Partial pressure of a gas is proportional to the concentration of that gas in a mixture or the concentration dissolved in a liquid Gases diffuse from regions of higher partial pressure to lower partial pressure Oxygen diffuses from alveolar air into blood CO 2 diffuses from blood into alveolar air

 Blood transports gases between the lungs and cells  Oxygen Transport: blood transports O 2 with hemoglobin  Oxyhemoglobin is unstable and releases its O 2 in regions where P O 2 is low  More O 2 is released when: Blood concentration of CO 2 increases Blood becomes more acidic Blood temperature increases

 May be carried in solution or bound to hemoglobin, or as a bicarbonate ion  Most is transport in the form of bicarbonate ions  Carbonic anhydrase: enzyme that speeds the reaction between CO 2 and H 2 O to form carbonic acid Dissociates to release H + and bicarbonate ions

 Anatomy of Breathing Flash Animation Anatomy of Breathing Flash Animation  12.uthscsa.edu/studentresources/Anatomyof Breathing3.swf