15.1 The Respiratory System The respiratory system works with the cardiovascular system to accomplish: The exchange of gases (O2 and CO2) between air and the blood The exchange of gases (O2 and CO2) between blood and tissue fluid Transport of gases to and from the lungs and the tissues

The Respiratory System

15.1 The Respiratory System The Nose Contains two nasal cavities Functions Warms air during inhalation Cleanses air-coarse hairs and mucus Humidifies air-wet surfaces of membrane Contain odor receptors Tear glands drain into nasal cavity

15.1 The Respiratory System The Trachea Connects larynx with primary bronchi Supported by C-shaped cartilage rings Cilia sweep mucus toward the pharynx Smoking can destroy cilia

15.1 The Respiratory System The Bronchial Tree Right and left primary bronchi Branch to secondary bronchi As airways become smaller, walls become thinner Each bronchiole leads into alveoli

15.1 The Respiratory System The Lungs Divided into lobes Right lung has 3 Left lung has 2 Lungs are covered by serous membrane called pleura

15.1 The Respiratory System The Alveoli Surrounded by blood capillaries Gas exchange occurs through the moist membranes Oxygen diffuses into blood Carbon dioxide diffuses into alveoli Alveoli must stay open to receive air Surfactant helps prevent them from closing

15.2 Mechanisms of Breathing Respiratory Volumes Tidal volume Amount of air moving in and out with each breath Vital capacity Maximum volume moved in and moved out in a breath Residual volume Amount of air always remaining in lungs

Inspiration

Expiration

15.2 Mechanisms of Breathing Respiratory Center Directly sensitive to CO2 and H+ When levels rise, respiratory center increases rate and depth of breathing Indirectly responsive to O2 Chemoreceptors in the carotid and aortic bodies Sensitive to oxygen levels in blood When levels decrease, impulses are sent to respiratory center Respiratory center then increases rate and depth of breathing

15.3 Gas Exchanges in the Body

15.3 Gas Exchanges in the Body External Respiration (takes place in lungs) Exchange of gas between air in alveoli and blood Gases exert pressure Partial pressure refers to the amount of pressure each gas in a mixture exerts Symbolized by Pco2 and Po2 Blood in pulmonary capillaries has a higher Pco2 than atmospheric air CO2 diffuses from blood into alveoli

15.3 Gas Exchanges in the Body External Respiration Continued Most CO2 is carried as bicarbonate ions (HCO3-) Carbonic anhydrase catalyzes the breakdown of carbonic acid (H2CO3)

15.3 Gas Exchanges in the Body External Respiration Continued Pressure gradient for oxygen is the reverse of carbon dioxide Po2 is low in pulmonary capillaries and high in alveoli Oxygen diffuses into blood Hemoglobin picks up oxygen and becomes oxyhemoglobin

15.3 Gas Exchanges in the Body Internal Respiration (takes place in tissues) Exchange of gas between systemic capillaries and tissues Partial pressure of oxygen is greater in capillaries than tissues Oxyhemoglobin gives up oxygen which diffuses out of the blood into tissues

15.3 Gas Exchanges in the Body Internal Respiration CO2 diffuses into the blood A small amount combines with hemoglobin Most CO2 combines with H2O Carbonic anhydrase speeds up the reaction

15.4 Disorders of the Respiratory System Disorder of the Upper Respiratory Tract Pharyngitis Inflammation of the throat May be caused by Streptococcus pyogenes (Strep throat) Severe sore throat, high fever, white patches in throat region Tonsillitis Tonsils (lymphoid tissue) become inflamed and enlarged Laryngitis Inflammation of the larynx Causes hoarseness Persistent laryngitis is one warning sign of cancer

15.4 Disorders of the Respiratory System Disorder of the Lower Respiratory Tract Choking Obstruction of the trachea Heimlich maneuver may expel blockage A tracheostomy is the insertion of a breathing tube into the trachea

15.4 Disorders of the Respiratory System Disorder of the Lower Respiratory Tract Acute bronchitis Infection of the primary and secondary bronchi Usually it is preceded by a viral infection that leads to a secondary bacterial infection Chronic bronchitis Airways are inflamed and filled with mucus Bronchi have undergone degenerative change including the loss of cilia Smoking is the most common cause

15.4 Disorders of the Respiratory System Disorder of the Lower Respiratory Tract Asthma A disease of the bronchi and bronchioles Wheezing, breathlessness, coughing Inflammation of the bronchioles Airways are usually sensitive to specific irritants Incurable but can be treated with medicines

15.4 Disorders of the Respiratory System Disorder of the Lower Respiratory Tract Pneumonia Viral or bacterial infection Bronchi or alveoli fill with fluid High fever, chest pain and headache

15.4 Disorders of the Respiratory System Disorder of the Lower Respiratory Tract Emphysema Damage to the walls of the alveoli A chronic and incurable disease Smoking is the major cause of this disease

Common Bronchiole and Pulmonary Diseases

Normal Lung versus Cancerous Lung