act as resonance chambers for speech mucosa warms and moistens the incoming air lightens facial bones
Connects nasal cavity and mouth to larynx and esophagus 1) nasopharynx- air passage pharyngotympanic (auditory) tube- allows middle air pressure to become equalized to atmospheric pressure Adenoids (pharyngeal) tonsils- mass of lymphoid tissue traps and destroys pathogens produces lymphocytes helps fight infection 2) oropharynx- serves as a common conduit for air and food palatine and lingual tonsils 3) laryngopharynx- accommodates both ingested food and air located at junction where tracheae and esophagus splits continuous with esophagus
Epiglottis- flexible elastic cartilage attached to the wall of the pharynx near the base of the tongue it closes the glottis in the respiratory tract (trachea) when food is swallowed Larynx- voice box; thyroid cart. that attaches to hyoid bone superior and cricoid inferior Provides open airway Junction for food and air Voice production
Olfactory tract Olfactory bulb Nasal conchae Route of inhaled air Olfactory epithelium
16 C-shaped rings of hyaline cartilage (thyroid +cricoid + tracheal cartilage's, includes epiglottis (elastic cart) make up larynx Laryngitis- inflammation of the vocal cords resulting in inability to speak; due to voice overuse, very dry air, bacterial infection, and inhalation of irritating chemicals Trachea- held open by rings of hyaline cartilage, so it won't collapse during pressure changes when breathing.
2 muscles involved with breathing: external intercostal muscles diaphragm Breathing controlled by: phrenic nerve from medulla pons
Lung Ventilation Inspiration 760 mm Hg 756 mm Hg Negative pressure draws air in
Lung Ventilation Expiration 768 mm Hg Positive pressure forces air out
Lung Volumes Tidal Volume- 500 ml Vital Capacity- 4800 ml Residual Volume- 1000-1200ml Total Lung Capacity- 4400-6400ml IRV- 2800 ml ERV- 1000-1200ml Dead Space- 150 ml What factors affect lung volume?
Restrictive- more diff. to get air in to lungs Loss of lung tissue Decrease in lungs ability to expand Decrease in ability to transfer O2 and CO2 in blood Diseases: Fibrosis, sarcoidosis, muscular disease, chest wall injury, pneumonia, lung cancer, pregnancy, obesity VC, TLC, RV, FRC
Obstructive- more diff. to get air out of lungs Airway narrows Increase in time it takes to empty lungs Diseases: Emphysema, chronic bronchitis, asthma VC, TLC, RV, FRC
Chronic bronchitis- (obstructive) inhaled irritants lead to chronic excessive mucous production and inflammation and fibrosis of that mucosa; the amt of air that can be inhaled; use bronco- dilators and inhalers Emphysema- (obstructive and restrictive) enlargement of alveoli; alveolar tissue is destroyed resulting in fewer and larger alveoli; inefficient air exchange; smoker's disease; amt of air that can be exhaled Asthma- (obstructive disorder) cold, exercise, pollen and other allergens; from 1979-1989 the number of asthmatic deaths doubles
Tuberculosis (TB)- (restrictive) infectious disease cause by bacterium Mycobacterium tuberculosis. Spread through air borne bacteria from infected person's cough. Total lung capacity declines Symptoms: fever night sweats, wt. loss, racking cough, and spitting up blood Polio- TLC declines (restrictive) Eliminated in U.S. and Western Hemisphere Still exists in Africa Lung cancer- promoted by free radicals and other carcinogens; very aggressive and metastasizes rapidly
The total pressure of a gas exerted by a mixture of gas is the sum of the gases exerted independently. Air% partial pressure (mm Hg) N 2 78.6597 O 2 21.0159 CO 2 0.040.3 H 2 O0.463.7 Total100760 Partial pressure is directly related to its % in the total gas mixture. E.g., at 1 atm PO 2 = 159 mm Hg
When a mixture of gas is in contact w/a liquid, each gas will dissolve in the liquid in proportion to its partial pressure. Gasses can go in and out of solution e.g., open soda, get CO 2 bubbles (CO 2 is under pressure)
It is caused when N 2 enters the blood circulation and the tissues. When extra N 2 leaves the tissues, large bubbles form. N 2 bubbles can travel throughout the system and into the lungs and blood routes. Treatment: hyperbaric chamber
Erythrocytes Function- transport respiratory gases Lack mitochondria. Why?
Hemoglobin Structure 1 RBC contains 250 million hemoglobin molecules Hemoglobin - quaternary structure 2 chains and 2 chains
Uptake of Oxygen by Hemoglobin in the Lungs High Concentration of O 2 in Blood Plasma High pH of the Blood Plasma O2 binds to hemoglobin to form oxyhemoglobin
Carbon Dioxide Chemistry in the Blood CO 2 + H 2 O H 2 CO 3 HCO 3 - + H + carbonicacid bicarbonateion enzyme = carbonic anhydrase
Transport of Carbon Dioxide from the Tissues to the Lungs 60-70% as bicarbonate dissolved in the plasma (slow reaction) 7-10% dissolved in the plasma as CO 2 20-30% bound to hemoglobin as HbCO 2 CO 2 + hemoglobin HbCO 2
Haldane Effect- the amt of CO 2 transported in the blood is markedly affected by the degree of oxygenation of the blood The lower the P0 2 and hemoglobin saturation w/O 2, the more CO 2 that can be carried by the blood
CO poisoning (hypoxemia hypoxia) CO binds 200x more readily w/hemoglobin acts as a competitive inhibitor symptoms: cherry red lips, confused, headache does not produce characteristic signs of hypoxia (cyanosis and respiratory distress) treatment: hyperbaric chamber
INQUIRY 1.Identify the lipoprotein molecule that reduces surface tension within the alveoli so they do not collapse during exhalation. 2.Even after the most forceful exhalation, a certain volume of air remains in the lungs. What is the volume of air called? 3.Describe the physical structure of alveoli. 4.What structures warm and moisten incoming air? 5.What body cavity are the lungs located? 6.What tissue lines the lungs? 7.What stimulates the breathing response? 8.Calculate total lung capacity given: RV= 1000, TV = 500, ERV = 1100, IRV = 2500, VC= 4100