Respiratory System

1. Respiratory System Dr. Michael P. Gillespie

2. Functions • Gas exchange. • Regulation of blood ph. • Contains receptors for the sense of smell. • Filters inspired air. • Produces sounds. • Rids the body of some water and heat in expired air.

3. Gas Exchange • Cells use oxygen (O2) for metabolic reactions that release energy from nutrient molecules and produce ATP. • These reactions release carbon dioxide (CO2). • The cardiovascular system and the respiratory system cooperate to supple O2 and eliminate CO2.

4. Components • Nose. • Pharynx (throat). • Larynx (voice box). • Trachea (windpipe). • Bronchi. • Lungs.

5. Upper Respiratory System • Nose. • Pharynx. • Associated structures.

6. Lower Respiratory System • Larynx. • Trachea. • Bronchi. • Lungs.

8. Functional Divisions • Conducting portion. • Interconnecting cavities and tubes both outside and within the lungs that filter, warm, moisten air and conduct it into the lungs. • Nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles. • Respiratory portion. • Tissues within the lungs where gas exchange occurs. • Respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.

9. Otorhinolaryngology • Diagnosis and treatment of the ears, nose and throat.

10. Pulmonologist • Diagnosis and treatment of disease of the lungs.

11. Nose • External and internal portions.

12. External Nose • Supporting framework of bone and hyaline cartilage covered with muscle and skin and lined with a mucous membrane. • Frontal bone, nasal bones, and maxillae form the bony framework.

13. External Nose • The cartilaginous framework consists of the septal cartilage, lateral nasal cartilages, and alar cartilages.

14. External Nose • The two openings are the external nares or nostrils. • Functions: • Warming, moistening, and filtering incoming air. • Detecting olfactory stimuli. • Modifying speech vibrations as they pass through large, hollow, resonating chambers. • Resonance refers to prolonging, amplifying, or modifying a sound by vibration.

15. Internal Nose • A large cavity in the anterior aspect of the skull. • Lies inferior to the nasal bone and superior to the mouth. • The internal nares or choanae provide communication between the external nose and the pharynx. • Ducts from the paranasal sinuses and the nasolacrimal ducts also open into the internal nose.

16. Internal Nose • Lateral walls: ethmoid, maxillae, lacrimal, palatine, and inferior nasal conchae bones. • Floor: the hard palate which consists of the palatine bones and the palatine process of the maxillae.

17. Internal Nose • Nasal cavity – the space within the internal nose. • The anterior portion just inside the nostrils is called the vestibule. • The nasal septum divides the cavity into right and left sides. • Primarily hyaline cartilage, but also the vomer, and perpendicular plate.

19. Air Filtration • The vestibule is lined by skin containing coarse hairs, which filter out large dust particles. • Three shelves are formed by the superior, middle, and inferior conchae. • The conchae divide the nasal septum into groove like passageways called the superior, middle, and inferior meatuses. • A mucous membrane lines the cavity and its shelves.

20. Air Filtration • The arrangement of the conchae and meatuses increases surface area in the internal nose. It traps water droplets during exhalation to prevent dehydration. • The olfactory receptors line the superior nasal conchae and adjacent septum (olfactory epithelium).

21. Air Filtration • Inspired air is warmed by blood in the capillaries. • Mucous secreted by goblet cells moistens the air and traps dust particles. • Cilia move the mucous and trapped particles towards the pharynx to be swallowed or spit out.

22. Rhinoplasty • “Nose job”. • The structure of the external nose is altered. • Often performed for cosmetic reasons. • Sometimes performed to repair a fractured nose or a deviated septum.

23. Pharynx • The pharynx or throat is a funnel shaped tube about 13 cm long. • It starts at the internal nares and extends to the cricoid cartilage (the most inferior cartilage of the larynx).

24. Pharynx • Its wall is composed of skeletal muscles and it is lined with a mucous membrane.

25. Pharynx • Functions: • Passageway for air and food. • Resonating chamber for speech sounds. • Houses the tonsils (participate in immune responses). • Anatomical regions: • Nasopharynx. • Oropharynx. • Laryngopharynx.

26. Nasopharynx • The nasopharynx is the superior portion of the pharynx. • Extends from the posterior nasal cavity to the soft palate. • 5 openings in its wall: • 2 internal nares. • Eustachian tubes (a.K.A. Auditory or pharyngotympanic). • Opening into the oropharynx.

27. Nasopharynx • Pharyngeal tonsils. • The nasopharynx is lined with pseudostratified ciliated columnar epithelium, which moves mucous down towards the inferior part of the pharynx. • The eustachian tubes help to equalize air pressure between the pharynx and middle ear.

28. Oropharynx • The intermediate portion of the pharynx. • Extends from the soft palate to the hyoid bone. • One opening – the fauces (throat), the opening from the mouth. • Common passageway for air, food, and drink. • Lined with nonkeratinized stratified squamous epithelium to withstand abrasion from food particles. • Palatine and lingual tonsils are found here.

29. Laryngopharynx • Inferior portion of the pharynx. • Otherwise known as the hypopharynx. • Opens to the esophagus posteriorly and the larynx anteriorly. • Both a respiratory and a digestive pathway. • Lined with nonkeratinzed stratified squamous epithelium.

31. Larynx • Voice box. • A short passageway that connects the laryngopharynx with the trachea. • Lies in the midline of the neck anterior to the 4th through 6th cervical vertebrae.

32. Larynx • Composed of 9 pieces of cartilage. • Thyroid cartilage (Adam’s apple).

33. Larynx • Epiglottis – a large leaf shaped piece of elastic cartilage. • During swallowing, the epiglottis closes off the glottis (vocal cords) and prevents food from entering the larynx and airways inferior to it. It shunts food to the esophagus.

34. Larynx • Cricoid cartilage. • A ring of cartilage that forms the inferior wall of the larynx. • This cartilage serves as the landmark for making an emergency airway (tracheostomy).

36. Voice Production • The mucous membrane of the larynx forms two pairs of folds. • Ventricular folds (false vocal cords) – superior. • Vocal folds (true vocal cords) – inferior. • If air is directed against the vocal folds they vibrate and produce sounds (phonation).

37. Voice Production • The greater the pressure of the air, the louder the sound. • Pitch is controlled by tension on the vocal folds. If they are pulled taught, the pitch raises. Decreasing muscular tension results in lower sounds. • Vocal folds are usually thicker and longer in males than in females resulting in a lower pitch.

38. Laryngitis & Cancer Of The Larynx • Laryngitis is an inflammation of the larynx. • It is often caused by a respiratory infection or irritants such as cigarettes or smoke.

39. Laryngitis & Cancer Of The Larynx • Chronic inflammation in long term smokers can cause a permanent hoarseness. • Cancer of the larynx is found almost exclusively in smokers. • Treatment consists of radiation therapy and / or surgery.

41. Trachea • The trachea (windpipe) is a tubular passageway for air that is about 12 cm long and 2.5 cm in diameter.

42. Trachea • It is anterior to the esophagus and extends from the larynx to the superior border of the 5th thoracic vertebra where it branches to form bronchi.

43. Trachea • Layers: • Mucosa. • Pseudostratified ciliated columnar epithelium and goblet cells. • Submucosa. • Hyaline cartilage. • 16 – 20 incomplete, horizontal rings that resemble the letter C. • The open part of each ring faces the esophagus and allows slight expansion of the esophagus into the trachea during swallowing. • The solid C shaped ring prevents collapse of the trachea. • Adventitia. • Areolar connective tissue that joins the trachea to the surrounding tissues.

44. Tracheostomy & Intubation • Several conditions can block airflow: • A crushing injury to the chest. • Inflammation of the mucous membrane causing swelling. • Vomit or another foreign object may be aspirated into it. • If the obstruction is superior to the larynx, a tracheostomy may be performed.

45. Tracheostomy & Intubation • A tracheostomy is an operation to make an opening into the trachea. • Intubation involves inserting a tube into the mouth or nose and passing it inferiorly through the larynx or trachea. The tube pushes any flexible obstruction out of the way. Mucous can be suctioned through the tube and the lumen provides a passageway for air.

46. Bronchi • The trachea divides into a right primary bronchus and a left primary bronchus at the superior border of T5. • Carina – the ridge where the trachea branches into the right and left bronchi. The mucous membrane is the most sensitive here and triggers the cough reflex. • Upon entering the lungs, the primary bronchi divide into secondary (lobar) bronchi – one for each lobe of the lung. 3 on the right and 2 on the left.

47. Bronchi • They then branch to tertiary (segmental) bronchi and eventually bronchioles. • Terminal bronchioles are the smallest branch. • This branching is referred to as the bronchial tree.

49. Bronchial Control • The amount of cartilage decreases as we move down the bronchial tree and the amount of smooth muscle increases. • With no supporting cartilage, muscle spasms can close of the airways as in an asthma attack.

50. Bronchial Control • Sympathetic nerve stimulation causes relaxation of the smooth muscles of the bronchioles through release of epinephrine and norepinephrine. • The parasympathetic division of the ANS and mediators of allergic reactions such as histamine cause contraction of bronchiolar smooth muscle.