Respiratory System. Functional Anatomy of the Respiratory System

Transcription

1 Respiratory System Overview of the Respiratory System s Job Major Duty Respiration Other important aspects ph control Vocalization Processing incoming air Protection Metabolism (ACE) What structures allow for these events? Functional Anatomy of the Respiratory System Respiratory organs Nose, nasal cavity, and paranasal sinuses Pharynx, larynx, and trachea Lungs Bronchi and smaller branches and alveoli Divided into: Conducting zone Respiratory zone 1

2 The Nose Functions Provides an airway for respiration Moistens and warms air Filters inhaled air Resonating chamber for speech also acting as a resonator are? Houses olfactory receptors Characteristics Size variation due to differences in nasal cartilages Skin is thin contains many sebaceous glands The Nasal Cavity External nares nostrils Divided by nasal septum Continuous with nasopharynx Posterior nasal apertures choanae Contains the nasal conchae Basic Anatomy of the Upper Respiratory Tract 2

3 Upper Respiratory Tract The Mucosa Two types of mucosa Olfactory mucosa houses olfactory receptors Respiratory mucosa lines nasal cavity Consists of: Pseudostratified ciliated columnar epithelium Goblet cells within epithelium Underlying layer of lamina propria Cilia move contaminated mucus posteriorly Upper Respiratory Tract The Pharynx Funnel shaped passageway Connects nasal cavity and mouth Divided into three locations Nasopharynx, oropharynx, and laryngopharynx Type of mucosal lining varies along its length The Upper Respiratory Tract The Nasopharynx Superior to the point where food enters Only an air passageway Closed off during swallowing Pharyngeal tonsil (adenoids) Located on posterior wall Destroys entering pathogens Have ciliated epithelial tufts Major epithelium present is stratified squamous with microvilli present Contains the opening to the pharyngotympanic (auditory) tube 3

4 The Upper Respiratory Tract The Oropharynx Arch like entranceway fauces Extends from soft palate to the epiglottis Epithelium is stratified squamous epithelium Two types of tonsils in the oropharynx Palatine tonsils in the lateral walls of the fauces Lingual tonsils embedded in the posterior surface of the tongue The Upper Respiratory Tract The Laryngopharynx Passageway for both food and air Starts at tip of epiglottis Ends at start of esophagus Lined with stratified squamous epithelium Continuous with the oropharynx anteriorly and the esophagus posteriorly The Larynx Voice production Length/Tension adjusted by cricoarytnoid muscles & vocalis (thyroarytenoid) muscles Affect? Loudness Sphincter function of the larynx Valsalva maneuver Food vs. Air Innervation of the larynx Via the vagus nerve s recurrent laryngeal branch 4

5 Anatomy of the Larynx The Trachea Descends into the mediastinum Divides into two main bronchi C shaped cartilage rings Bronchi in the Conducting Zone Bronchial tree extensively branching respiratory passageways Primary bronchi (main bronchi) largest bronchi Right main bronchi wider and shorter than the left 5

6 Bronchi in the Conducting Zone Secondary (lobar) bronchi Three on the right Two on the left Tertiary (segmental) bronchi Branch into each lung segment (bronchopulumonary segments) Bronchioles little bronchi, less than 1 mm in diameter Terminal bronchioles less than 0.5 mm in diameter Bronchopulmonary Segments Figure 21.14a Changes in Tissue Composition along Conducting Pathways Supportive connective tissues change C shaped rings replaced by cartilage plates Epithelium changes First, pseudostratified ciliated columnar Replaced by simple columnar, then simple cuboidal epithelium Smooth muscle becomes important 6

7 The Respiratory Zone Consists of air exchanging structures Respiratory bronchioles branch from terminal bronchioles Lead to alveolar ducts Alveolar ducts branch from respiratory bronchioles Lead to alveolar sacs (alveoli) Structures of the Respiratory Zone Anatomy of Alveoli and the Respiratory Membrane Respiratory Membrane alveolar component capillary component 7

8 The Respiratory Zone Alveoli consist of Type I alveolar cells Type II alveolar cells (Septal Cells) Scattered among type I cells Cuboidal epithelial cells Secrete surfactant Dust Cells Aka free alveolar macrophages Basal lamina Microscopic Anatomy of Alveoli and the Respiratory Membrane The Pleurae A double layered sac surrounding each lung Parietal pleura Visceral pleura Pleural cavity Potential space between the visceral and parietal pleurae Pleurae help divide the thoracic cavity Central mediastinum Two lateral pleural compartments 8

9 Gross Anatomy of the Lungs Anterior View of Thoracic Structures Lung Diagram of the Pleurae and Pleural Cavities 9

10 Blood Supply and Innervation of the Lungs Pulmonary arteries deliver oxygen poor blood to the lungs Pulmonary veins carry oxygenated blood to the heart Innervation Sympathetic, parasympathetic, and visceral sensory fibers Parasympathetic constrict airways Sympathetic dilate airways The Mechanisms of Ventilation Two phases of pulmonary ventilation Inspiration inhalation Expiration exhalation Inspiration In order to get air into the lungs, a pressure gradient must exist. Action of the diaphragm diaphragm flattens Action of intercostal muscles contraction raises the ribs Deep inspiration requires Scalenes, sternocleidomastoid, and pectoralis minor Erector spinae extends the back All this increases the thoracic volume which corresponds to a decrease in intra alveolar pressure (who s gas law?) 10

11 Expiration Quiet expiration chiefly a passive process Inspiratory muscles relax Diaphragm moves superiorly Volume of thoracic cavity decreases Forced expiration an active process Produced by contraction of: The oblique and transversus abdominis muscles Changes in Thoracic Volume Changes in Thoracic Volume 11

12 Neural Controls of Ventilation Respiratory centers generate baseline respiration rate in medulla oblongata in the pons Chemoreceptors Central and Peripheral Other receptors 12