23-1 Chapter 23 Respiratory System

23-2 Respiration Ventilation: Movement of air into & out of lungs External respiration: Gas exchange b/n air in lungs & blood –Transport of O 2 and CO 2 in the blood Internal respiration: Gas exchange b/n the blood & tissues

23-3 Respiratory System Functions Gas exchange: O 2 enters blood & CO 2 leaves Regulation of blood pH: Altered by changing blood CO 2 levels Voice production: Movement of air past vocal folds makes sound & speech Olfaction: Smell occurs when airborne molecules drawn into nasal cavity Protection: Against microorganisms by preventing entry & removing them

23-4 Respiratory System Divisions Upper tract –Nose, pharynx & associated structures Lower tract –Larynx, trachea, bronchi, lungs

23-5 Nose and Pharynx Nose –External nose –Nasal cavity Functions –Passageway for air –Cilia cleans the air –Mucous humidifies (moistens air inhaled) –Capillaries warm air –Smell –Along with paranasal sinuses are resonating chambers for speech Pharynx –Common opening for digestive & respiratory systems –Three regions Nasopharynx Oropharynx Laryngopharynx

23-6 Larynx Functions –Maintain an open passageway for air movement –Epiglottis & vestibular folds prevent swallowed material from moving into larynx (can move to cover trachea) –Vocal folds are primary source of sound production

23-7 Structure of Larynx –AKA voice box –Thyroid cartilage: AKA Adam’s apple Protects vocal cords Moves when you swallow –Epiglottis: closes off larynx so food & liquid travel down the esophagus

23-8 Voice Production False vocal cords: assist w/ hold breath True vocal cords: –Space between them called glottis –Vibration produces sound –In combination with tongue, mouth, & nose to produce words

23-9 Concept Check 1.Name the functions of the respiratory system. -Gas exchange; regulation of blood pH; olfaction; protection 2.How is the respiratory system divided? Name the parts of each. -Upper (Nose, Pharynx, Assoc. Structures); -Lower (Larynx, Trachea, Bronchi, Lungs) 3.Name the accessory structures of the nose, and describe their function. -Cilia (cleans air); Mucus (moistens air), Capillaries (warms air) 4.The larynx is also known as the… -Voice Box

23-10 Trachea Windpipe Divides to form –Primary bronchi –Carina: Cough reflex Insert Fig 23.5 all but b

23-11 Organs of Respiration Trachea: –AKA windpipe –Smooth muscle supported by C-shaped rings of cartilage food can travel down esophagus easier –Passageway for air from larynx to bronchi –Lined w/ cilia & mucous

23-12 Tracheobronchial Tree Conducting zone –Trachea to terminal bronchioles which is ciliated for removal of debris –Passageway for air movement –Cartilage holds tube system open & smooth muscle controls tube diameter Respiratory zone –Respiratory bronchioles to alveoli –Site for gas exchange

23-13 Organs of Respiration Bronchi: –Left & right primary bronchi branch off trachea –Lined w/ cilia –Supported by cartilage

23-14 Bronchial Tree Primary bronchi Secondary bronchi Tertiary bronchi bronchioles Terminal bronchioles Respiratory bronchioles Alveolar ducts Alveolar sacs alveoli

23-15 Bronchioles and Alveoli

23-16 Alveolus and Respiratory Membrane

23-17 Lungs Two lungs: Principal organs of respiration –Right lung: Three lobes –Left lung: Two lobes

23-18 Organs of Respiration Alveoli: –Extremely thin-walled sacs covered w/ capillaries –CO 2 & O 2 move by diffusion across the respiratory membrane –About 300 million alveoli in two lungs –Size of a tennis court

23-19 Organs of Respiration Alveoli: –Surfactant lines the alveoli to aid diffusion & decrease surface tension –To prevent the alveoli from collapsing & sticking shut

23-20 Pleura Pleural fluid produced by pleural membranes –Acts as lubricant –Helps hold parietal & visceral pleural membranes together

23-21 Concept Check 1.The trachea is also known as… -Windpipe 1.How is the trachea structured & why? -C-Shaped rings of cartilage (allows passage of food to move easily) 2.Describe the bronchial tree.

23-22 Ventilation Movement of air into and out of lungs Air moves from area of higher pressure to area of lower pressure (AKA Diffusion) Pressure is inversely related to volume

23-23 Inspiration Breathing in When pressure in the lungs is less than the air pressure in the atmosphere Diaphragm— will contract and lower, increasing the size of the thoracic cage

23-24 Inspiration Increased volume will decrease the pressure & the lungs will expand

23-25 Expiration Breathing out When the pressure inside the lungs is greater than the pressure in the atmosphere Diaphragm— relaxes and rises; decreases the size of the thoracic cage

23-26 Expiration Decreased volume will increase pressure & lungs will decrease and push air out

23-27 Internal Respiration Exchange of O 2 and CO 2 between tissue capillaries and tissue cells CO 2 moves from high concentration in cells to low concentration in blood

23-28 External Respiration Conversion of deoxygenated blood to oxygenated blood –Aided by thin membranes –Large surface area –Narrow capillaries

23-29 Concept Check 1.What is the diffusion? 2.What is the difference between inspiration and expiration? 3.What happens to the diaphragm? Be specific.

23-30 Changing Alveolar Volume Lung recoil –Causes alveoli to collapse resulting from Elastic recoil and surface tension –Surfactant: Reduces tendency of lungs to collapse Pleural pressure –Negative pressure can cause alveoli to expand –Pneumothorax is an opening between pleural cavity & air that causes a loss of pleural pressure

23-31 Compliance Measure of the ease with which lungs & thorax expand –The greater the compliance, the easier it is for a change in pressure to cause expansion –A lower-than-normal compliance means the lungs and thorax are harder to expand Conditions that decrease compliance –Pulmonary fibrosis –Pulmonary edema –Respiratory distress syndrome

23-32 Pulmonary Volumes Tidal volume –Volume of air inspired or expired during a normal inspiration or expiration Inspiratory reserve volume –Amount of air inspired forcefully after inspiration of normal tidal volume Expiratory reserve volume –Amount of air forcefully expired after expiration of normal tidal volume Residual volume –Volume of air remaining in respiratory passages and lungs after the most forceful expiration

23-33 Pulmonary Capacities Inspiratory capacity –Tidal volume plus inspiratory reserve volume Functional residual capacity –Expiratory reserve volume plus the residual volume Vital capacity –Sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume Total lung capacity –Sum of inspiratory and expiratory reserve volumes plus the tidal volume and residual volume

23-34 Spirometer and Lung Volumes/Capacities

23-35 Minute and Alveolar Ventilation Minute ventilation: Total amount of air moved into & out of respiratory system per minute Respiratory rate or frequency: Number of breaths taken per minute Anatomic dead space: Part of respiratory system where gas exchange does not take place Alveolar ventilation: How much air per minute enters the parts of the respiratory system in which gas exchange takes place

23-36 Physical Principles of Gas Exchange Partial pressure –The pressure exerted by each type of gas in a mixture Diffusion of gases through liquids –Concentration of a gas in a liquid is determined by its partial pressure and its solubility coefficient

23-37 Physical Principles of Gas Exchange Diffusion of gases through the respiratory membrane –Depends on membrane’s thickness, the diffusion coefficient of gas, surface areas of membrane, partial pressure of gases in alveoli and blood Relationship between ventilation and pulmonary capillary flow –Increased ventilation or increased pulmonary capillary blood flow increases gas exchange –Physiologic shunt is deoxygenated blood returning from lungs

23-38 Oxygen & Carbon Dioxide Diffusion Gradients Oxygen –Moves from alveoli into blood. Blood is almost completely saturated with oxygen when it leaves the capillary –C0 2 in blood decreases because of mixing with deoxygenated blood –Oxygen moves from tissue capillaries into the tissues Carbon dioxide –Moves from tissues into tissue capillaries –Moves from pulmonary capillaries into the alveoli

23-39 Hemoglobin and Oxygen Transport Oxygen is transported by hemoglobin (98.5%) and is dissolved in plasma (1.5%)

23-40 Transport of Carbon Dioxide Carbon dioxide is transported as bicarbonate ions (70%) in combination with blood proteins (23%) and in solution with plasma (7%)

23-41 Herring-Breuer Reflex Limits the degree of inspiration and prevents overinflation of the lungs –Infants Reflex plays a role in regulating basic rhythm of breathing and preventing overinflation of lungs –Adults Reflex important only when tidal volume large as in exercise

23-42 Ventilation in Exercise Ventilation increases abruptly –At onset of exercise –Movement of limbs has strong influence –Learned component –Decreases slightly Ventilation increases gradually –After immediate increase, gradual increase occurs (4-6 minutes) –Anaerobic threshold is highest level of exercise without causing significant change in blood pH If exceeded, lactic acid produced by skeletal muscles

23-43 Disorders Asthma— spasms of smooth muscle in the bronchioles Lung cancer –Constant irritation produces excess mucous and puts unnecessary stress on the bronchi –Alveoli destroyed by WBC’s acting on the irritation –Structural cells disappear and cancer cells take over

23-44 Disorders Emphysema— alveolar walls lose their elasticity –Some alveoli merge and reduce volume –Have to work voluntarily to exhale Bronchitis— inflammation of the bronchi –Creates site for infection and increases mucous

23-45 Disorders Pneumonia— infection or inflammation of the alveoli Tuberculosis (TB)— bacterial infection that destroys lung tissue and is replaced by non-elastic connective tissue

23-46 Disorders Respiratory Distress Syndrome (RDS) –Lack of surfactant makes breathing difficult –Alveoli are sticking together –Occurs in infants Pulmonary Embolism –blood clot obstructs circulation to lung tissue & tissue dies

23-47 Disorders Respiratory Failure –Not enough O 2 to maintain metabolism –Cannot eliminate enough CO 2 –Caused by: Drugs Stroke CO poisoning shock

23-48 Disorders Colds and Flu— viral infections Sudden Infant Death Syndrome (SIDS) –Crib death –Occurs between 1 week and 12 months –Cause is unknown –Baby stops breathing

23-49 Disorders Laryngitis— vocal cords Pharyngitis— sore throat Rhinitis— lining of the nose

23-50 Effects of Aging Vital capacity and maximum minute ventilation decrease Residual volume and dead space increase Ability to remove mucus from respiratory passageways decreases Gas exchange across respiratory membrane is reduced