 Otorhinolaryngology - branch of medicine that deals with the ears, nose and throat  Pulmonologist – specialist in the diagnosis and treatment of lung disease

1. Respiration -exchange of gases within the body: O 2 & CO 2 2. Regulates blood pH 3. Contains receptors for smell 4. Filters inspired air 5. Sound production

 Pulmonary Ventilation (breathing) › Gas exchange between atmosphere and the lungs  External Respiration › Gas exchange between lungs & pulmonary capillaries (pulmonary capillary blood gains O 2, loses CO 2 )  Internal Respiration › Gas exchange between systemic capillaries & body tissue cells (systemic capillary blood gains CO 2, loses O 2 )

 1. The Nose › Warms, moistens & filters air › Detects odors › Modifies speech vibrations › Conchae & meatuses  Increase surface area  Trap exhaled water droplets during exhalation  Prevents dehydration

 Goblet cells secrete mucus › Moistens air › Traps debris  Cilia- tiny hairs that trap debris  Blood capillaries – warm inhaled air

 Stimulus irritates nasal mucosa  Spasmodic contraction of respiratory muscles occurs  Air focefully expelled out of nose & mouth  Sneezes can travel up to 200 mph  Sputum can be spread 2-3 meters

 2. The Pharynx › Part of both GI Tract & Respiratory Tract › Passageway for both food and air › Resonating chamber for speech sounds › Houses the tonsils › 3 Regions of Pharynx  Nasopharynx – 5 openings (internal nares, eustacian tubes and into oropharynx)  Oropharynx – respiratory & digestive function  Laryngopharynx – contains the epiglottis, which is a flap of cartilage that covers the glottis during swallowing.  Glottis – opening to the larynx/trachea

 3. The Larynx › “Voice box” › Connects laryngopharynx with the trachea › Lies anterior to C 4 – C 6 Vertebrae › Composed of cartilage › Air passing across vocal folds & vibration of folds creates sound › Pharynx, mouth, nasal cavity: act as resonating chambers to give sound human quality › Muscles of face, mouth & tongue allow for enunciation

 Pitch of voice is controlled by tension on the vocal cords › More tension = higher pitch › Less tension = lower pitch  Men have longer, thicker vocal cords that vibrate more slowly which creates a lower pitch › This is due to testosterone

 4. The Trachea › Windpipe › 12 cm in length; 2.5 cm in diameter › Anterior to the esophagus › Contains arcs (rings) of cartilage – helps to prevent collapse during breathing › Divides at carina (T-5) into right and left primary bronchi

Nose Nasal Cavity Pharynx Primary Bronchi Secondary Bronchi LungsTertiary Bronchi Bronchioles Terminal Bronchioles Respiratory Bronchioles Alveolar Ducts Alveoli

 Right lung: 3 lobes  Left lung: 2 lobes  Pleural membrane - (2 layers) covers each lung  Pleural cavity - space between layers; contains lubricating fluid  Hilus - region where primary bronchi, blood and lymph vessels, and nerves enter or exit the lung

 Tiny air sacs  300 million  Very thin tissue: 0.5 μm  Diffusion of gases occurs here (exchange of CO 2 and O 2 between lungs & blood)  Contains macrophages, which are cells that remove dust/debris  Alveoli secrete fluid for moisture › Contains surfactant – lowers the surface tension of alveolar fluid to prevent alveolar collapse

 Lungs receive blood from two sets of arteries › Pulmonary Arteries – bring deoxygenated blood (O 2 poor blood) to the lungs from the body › Bronchial Arteries – (branch from the aorta) bring oxygenated blood (O 2 rich blood) to the lungs from the heart  Pulmonary Veins – bring O 2 rich blood to the heart from the lungs

 Gases are exchanged between atmosphere & lung alveoli  O 2 in or CO 2 out  Due to differences in pressure when respiratory muscles contract & relax  Inspiration – breathing in  Expiration – breathing out  Boyle’s Law explains how this occurs

 The pressure of a gas varies inversely with the volume › If pressure goes up, volume goes down › If pressure goes down, volume goes up

 Diaphragm contracts (flattens), lungs expand  Volume of lungs increases  Pressure of lungs decreases  Air moves into lungs  Inhalation is an ACTIVE process: it requires muscle contraction & ATP

 Diaphragm relaxes – returns to “dome” shape  Pressure in lungs increases  Air moves out of lungs (volume of lungs decrease)  Exhalation is a PASSIVE process: it does not require muscle contraction & ATP

 Exchange of O 2 and CO 2 between alveoli and blood in pulmonary capillaries  Occurs by passive diffusion  Controlled by two gas laws: › Dalton’s Law › Henry’s Law

 Each gas in a mixture of gases exerts its own pressure as if all the other gases were not present  This is its partial pressure (P x ) › Ex.; Atmospheric air is made up of N 2, O 2, H 2 O, CO 2 and other gases › P N 2 + P O 2 + P H 2 O + P CO 2 + P other = P total › P total = 760 mm Hg

 The gases will diffuse from the area of higher pressure to the area of lower pressure › Ex.; if O 2 is high in alveoli & low in blood, O 2 will diffuse across the alveoli and into the blood › **it determines the movement of O 2 between:  Atmosphere & lungs  Lungs & blood  Blood & body cells

 the quantity of a gas that will dissolve in a liquid is proportional to the partial pressure of the gas and its solubility coefficient  If a gas has high partial pressure, and a high solubility coefficient = high gas content in solution

 Oxygen crosses into blood because: › P O 2 (alveolar air) = 105 mm Hg › P O 2 (deoxygenated blood in pulmonary capillaries) = 40 mm Hg › …so O 2 moves from alveoli to blood  Carbon dioxide crosses into alveoli because: › P CO 2 (deoxygenated blood in pulmonary capillaries) = 45 mm Hg › P CO 2 (alveolar air) = 40 mm Hg › …so CO 2 moves from blood to alveoli

 Rate of gas exchange depends on › 1. partial pressure difference of gases › 2. surface area for gas exchange  Bigger the area, the higher the rate of exchange › 3. diffusion distance  Smaller the distance, the higher the rate of exchange

 Exchange of gases at the cellular level (Dalton’s Law applies)  O 2 leaves blood and diffuses into cell  CO 2 leaves cells and diffuses into blood

 O 2 does not dissolve well in water  Transportation requires hemoglobin  Hemoglobin – an iron-rich protein that turns bright red when combined with O 2  Oxyhemoglobin – 1 hemoglobin + 4 O 2

 Dissolves well in water  Most found in blood as bicarbonate ions  Blood detects this & transports it to lungs to be exhaled  Controls rate of breathing: › High ion level – high respiratory rate › Low ion level – low respiratory rate  Medulla oblongata – part of brain that controls the respiratory rate

 Adult – 12 breaths/min  Tidal volume – volume of one breath ~ 500ml  Spirometer – device used to measure volume of respiration  Residual volume – air that remains in lungs after maximum exhalation (~1200 ml) › Prevents lung collapse › Can’t be measured with spirometer