Ventilation - moves air to and from alveoli

1. Functions of Respiratory System Ventilation - moves air to and from alveoli Gas exchange between air and circulating blood Defend respiratory system from pathogens Help homestasis of: blood volume, pH, and pressure Permit vocal communication

2. Respiration • Ventilation- environment and lungs • External Respiration – alveoli and blood • Internal respiration – Blood and cells • Cellular Respiration – Biochemical inside cell

3. Respiratory organs • Respiratory organs • Nose, nasal cavity, and paranasal sinuses • Pharynx, larynx, and trachea • Bronchi and smaller branches • Lungs and alveoli • Divided into: • upper • lower

4. External nares

5. Upper respiratory system • Nose • Nasal cavity • Pharynx • Functions • Warm, Filter and Humidify • incoming air • Lower Respiratory System • Larynx • Trachea • Bronchi • Bronchioles • Alveoli

6. The Nose • Provides an airway for respiration • Moistens and warms air • Filters inhaled air • Houses olfactory receptors

8. PARANASAL SINUSES

9. Respiratory Epithelium. • Lines conducting portions • Pseudostratified ciliated columnar epithelium with goblet cells PSCC • Produces mucus to trap foreign particles

10. Respiratory Epithelium.

11. cilia rhythmically ‘sweeps’ debris up to be swallowed or expelled at pharynx • Mucus escalator • Alveolar macrophage • Hairs in nose • Cilia - lining respiratory tract

12. External nares • Open into nasal cavity • Vestibule guarded by hairs • Nasal cavity • Superior, middle and inferior meatuses • Narrow grooves and conchal surfaces • Hard palate • Nasal and oral cavities • Soft palate • Superior nasopharynx and pharynx • Internal nares • Between nasal cavity and nasopharynx

13. The Pharynx Shared by digestive and respiratory systems • Nasopharynx • Superior portion: from internal nares to uvula. • Oropharynx • Continuous with oral cavity • Laryngopharynx • Between hyoid and entrance to esophagus

14. 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 • Contains the opening to the auditory tube

15. Oropharynx • Extends from soft palate to the epiglottis • Epithelium is stratified squamous epithelium • Two tonsils in the oropharynx • Palatine tonsils – in the lateral walls • Lingual tonsils – covers the posterior surface of the tongue

16. Laryngopharynx • Passageway for both food and air • Lined with stratified squamous epithelium • Continuous with the esophagus and larynx

17. The Lower Respiratory System • Surrounds glottis - air passes through glottis to reach lungs • Epiglottis - prevents solids from entering respiratory system Larynx

18. During swallowing, elevation of the larynx folds epiglottis over the glottis, steering materials into the esophagus.

19. Trachea • Submucosa includes “C” rings of cartilage • Tracheal cartilages • Stiffen tracheal walls and protect airway • Posterior wall distorts allowing food passage through esophagus

22. Left and Right 1o Bronchi • Right and left primary bronchi • Trachea branches within mediastinum • Bronchial tree • Enters lungs at hilus • Root of lung • Bronchus, primary vessels, nerves • Bronchial tree – extensively branching respiratory passageways • Primary bronchi (main bronchi) – largest bronchi • Right main bronchi – wider and shorter than the left

23. Lungs • Right lung has three lobes • Superior lobar, middle lobar and inferior lobar bronchi • Left lung has two lobes • Superior lobar and inferior lobar bronchi • Cardiac notch

26. Secondary (lobar) bronchi • Three on the right • Two on the left • Tertiary (segmental) bronchi • Branch into each lung segment • Bronchioles – little bronchi, less than 1 mm in diameter • Terminal bronchioles – less than 0.5 mm in diameter

28. Bronchi and Bronchioles

29. For clarity, the degree of branching has been reduced: an airway branches approximately 23 times before reaching the level of a lobule.

30. Fig 24.11

31. Alveolus – cells and composition • Simple squamous epithelium (type I) • Septal cells (type II) • Produce surfactant • Alveolar macrophages (dust cells) • Patrol epithelium • Engulf foreign particles

32. Basic structure of a lobule, cut to reveal the arrangement between the alveolar ducts and alveoli.

33. Respiratory Membrane • Respiratory Membrane (blood-air Barrier) • “point of gas exchange” • Aveolar Epithelium simple squamous epithelia • Fused basement membrane • Capillary endothelium simple squamous epithelia

34. Respiratory Epithelium • Air epithelia tissue • Nasal cavity stratified squamous • Nasopharynx PSCC • Oropharynx stratified squamous • Laryngopharynx stratified squamous • Larynx PSCC • Trachea PSCC • Rt./Lt. primary bronchi PSCC • Secondary (lobar) bronchi PSCC • Tertiary (segmental) bronchi PSCC • Terminal bronchioles simple cuboidal • Respiratory bronchioles simple cuboidal • Alveolar duct simple squamous • Alveolar sac simple squamous • Alveolus simple squamous

35. Ep=pscc Sumb=tunica submucosa Cart=tracheal ring Adv=tunica adventitia

36. Respiratory Muscles Ventilation - movement of air into and out of lungs.

37. Eupnea - normal quite breathing at rest. Inspiration:  volume of thoracic cavity. Muscle activity required: Diaphragm External Intercostals Sternocleidomastoid

38. When Forcefully exhaling (hypereupnea): Muscles used: Internal Intercostals Rectus abdominis Transverse abdominis, Internal and External obliques.

39. Bronchial asthma – a type of allergic inflammation • A hypersensitivity to irritants in the air or to stress • Asthma attacks characterized by: • Contraction of bronchiole smooth muscle • Secretion of mucus in airways • Chronic obstructive pulmonary disease (COPD) • Airflow into and out of the lungs is difficult • Obstructive emphysema • Chronic bronchitis • History of smoking

40. Cystic fibrosis (CF) – inherited disease • Exocrine gland function is disrupted • Respiratory system affected by: • Oversecretion of viscous mucus • Epistaxis – nosebleed • Epiglottitis – inflammation and swelling of the epiglottis • Dyspnea – difficulty in breathing • Apnea – cessation of breathing