2Respiratory TractConducting passageways carrying air to and from the alveoliUpper respiratoryNasal CavityLarynxPharynxLower passagewaysTracheaLungsBronchiBronchiolesAlveoliDiaphragmPathwaynasal cavities (or oral cavity) → pharynx → trachea → primary bronchi (right & left) → secondary bronchi → tertiary bronchi → bronchioles → alveoli
3Nasal Cavity/Nose Functions Selected anatomical features Provides an airway for respirationMoistens and warms entering airFilters and cleans inspired airResonating chamber for speechDetects odors in the airstreamSelected anatomical featuresVibrissae (guard hairs) – stiff hairs that filter large particles from the airNasal cilia – hair-like projections that propel trapped particles towards the throat for digestion by digestive enzymesRich supply of capillaries warm the inspired airNasal conchae – folds in the mucous membrane that increase air turbulence and ensures that most air contacts the mucous membranesOlfactory mucosa – mucous membranes that contain smell receptorsRespiratory mucosa – pseudostratified ciliated columnar epithelium containing goblet cells that secrete mucusMucusStickiness traps inhaled particlesLysozyme kills bacteriaLymphocytes and IgA antibodies protect against bacteria
7Pharynx Three regions of the pharynx Nasopharynx – air passage (pseudostratified columnar epithelium)Oropharynx – passageway for air, food, and drink (stratified squamous epithelium)Laryngopharynx – passageway for air, food, and drink (stratified squamous epithelium)
8Larynx Functions 1. Keeps food and drink out of the airway 2. Sound production3. Acts as a sphincter during abdominal straining (ex. during defecation and heavy lifting)
9Larynx Selected anatomical features Nine c-rings of hyaline cartilage form the framework of the larynxMuscular walls aid in voice production and the swallowing reflexGlottis – the superior opening of the larynxEpiglottis – prevents food and drink from entering airway when swallowingFalse vocal cords – aid in closing the glottis when swallowingTrue vocal cords – produce sound when air passes between themThe shorter and thinner these membranes are, the faster air moves over them – produces high pitched soundsThe longer and thicker these membranes are, the slower air moves over them – produces low pitched sounds
11Trachea Functions Air passageway 2. Cleans, warms, and moistens incoming air3. Selected anatomical featuresRings of hyaline cartilage – reinforce the trachea and keep it from collapsing when you inhaleCiliated pseudostratified epithelium – traps inhaled debris and propels mucus up to the pharynx where it is swallowed
16Function - Solely an air passageway Selected anatomical features1. Left and right primary bronchi branch off from trachea2. Once the left and right primary bronchi enter the lungs they are subdivided into smaller tubes:Secondary bronchi (one for each lobe) → tertiary bronchi → bronchioles → terminal bronchioles → respiratory bronchioles → alveolar ducts → alveolar sacs3. Alveolar sacs are clusters of alveoli4. Alveoli are the site of gas exchange5. Other tissue types present in the alveolia. Smooth muscle rings aid in resistance to air flowb. Elastic connective tissue fibers aid in expelling air from the lungs
25Patterns of BreathingApnea – temporary cessation of breathing (one or more skipped breaths)Dyspnea – labored, gasping breathing; shortness of breathEupnea – Normal, relaxed, quiet breathingHyperpnea – increased rate and depth of breathing in response to exercise, pain, or other conditionsHyperventilation – increased pulmonary ventilation in excess of metabolic demandHypoventilation – reduced pulmonary ventilationOrthopnea – Dyspnea that occurs when a person is lying downRespiratory arrest – permanent cessation of breathingTachypnea – accelerated respiration
26Clinical Disorders and Diseases of the Respiratory System Hypoxia – deficiency of oxygen in a tissue or the inability to use oxygenOxygen toxicity – excess oxygen, causing the build up of peroxides and free radicalsChronic obstructive pulmonary diseases (COPD) – long-term obstruction of airflow and a substantial reduction in pulmonary ventilationChronic bronchitis – cilia are immobilized and reduced in number; goblet cells increase their production of mucus → mucus clogs the airways and breeds infectionEmphysema – alveolar walls break down and the surface area of the lungs is reducedAsthma – allergens trigger the release of histamine and other inflammatory chemicals that cause intense bronchoconstriction. In asthma, periodic constriction of the bronchi and bronchioles makes it more difficult to breathe in and, especially, out. Attacks of asthma can be triggered by airborne irritants such as chemical fumes and cigarette smoke airborne particles to which the patient is allergic.Lung cancer –most common cancer and most common cause of cancer deaths in U.S. males. There are several forms of lung cancer, but the most common (and most rapidly increasing) types are those involving the epithelial cells lining the bronchi and bronchioles. Ordinarily, the lining of these airways consists of two layers of cells. Chronic exposure to irritants causes the number of layers to increase. The ciliated and mucus-secreting cells disappear and are replaced by a disorganized mass of cells with abnormal nuclei. If the process continues, the growing mass penetrates the underlying basement membrane. Malignant cells can break away and be carried in lymph and blood to other parts of the body where they may lodge and continue to proliferate. It is this metastasis of the primary tumor that eventually kills the patient.
27Clinical Disorders and Diseases of the Respiratory System Acute rhinitis – the common coldLaryngitis – inflammation of the vocal foldsPneumonia – lower respiratory infection of the alveoli that causes fluid build up in the lungs. It can be caused by many kinds of both bacteria (Streptococcus pneumoniae) and viruses. Tissue fluids accumulate in the alveoli reducing the surface area exposed to air. If enough alveoli are affected, the patient may need supplemental oxygen.Sleep apnea – Cessation of breathing for 10 seconds or longer during sleepTuberculosis – pulmonary infection with Mycobacterium tuberculosis; reduces lung compliancePleuritis - Inflammation of the pleura, producing more than the normal amount of fluid, causing a pleural effusion. The pain fibers of the lung are located in the pleura. When this tissue becomes inflamed, it results in a sharp pain in the chest that is worse with breathing in. Other symptoms of pleurisy can include cough, chest tenderness, and shortness of breath.Cystic fibrosis - caused by inheriting two defective CFTR genes, a transmembrane protein needed for the transport of Cl− ions out of the epithelial cells of the lung thus enabling water to follow by osmosis. Diminished CFTR function reduces the water content of the fluid in the lungs making it more viscous and difficult for the ciliated cells to move it up out of the lungs. The accumulation of mucus plugs the airways interfering with breathing and causing a persistent cough. Cystic fibrosis is the most common inherited disease in the U.S. white population.