The Respiratory System

1. 22 P A R T A The Respiratory System

2. Questions • 1. Why do we breath oxygen? What is the ultimate role of O2 in the body? • 2. Why is the majority of our respiratory system inside our body?

3. Oxygen’s Journey • 98% of the O2 serves to make ATP by going inside the mitochondrion and becoming the terminal acceptor of electrons in the Electron Transport Chain • 2% unfortunately becomes free radicals causing unwanted oxidation

4. Figure 3.2

5. Figure 3.17

7. Figure 24.5

8. Figure 24.7

9. Figure 24.9

10. Cytochrome Oxidase Figure 24.8

11. Why is the majority of our respiratory system inside our bodies? • When living creatures left the waters and came to the terrestrial (land) environment – the respiratory system had to be internalized or “the respiratory epithelium would dry out.” • But still needed lots of surface area for enough diffusion of oxygen to supply the trillions of body cells in accordance with Fick’s Diffusion Equation • In order to not make body larger but still have lots of diffusion surface area – must branch the respiratory system inside the body – 70 meters squared –tennis court size

12. Respiratory System • Consists of the respiratory and conducting zones • Respiratory zone: • Site of gas exchange • Consists of bronchioles, alveolar ducts, and alveoli

13. Respiratory System • Conducting zone: • Conduits for air to reach the sites of gas exchange • Includes all other respiratory structures (e.g., nose, nasal cavity, pharynx, trachea) • Respiratory muscles – diaphragm and other muscles that promote ventilation PLAY InterActive Physiology ®: Anatomy Review: Respiratory Structures, page 3

14. Respiratory System Figure 22.1

15. Upper vs. Lower Respiratory System • The upper respiratory tract consists of the nasal cavity (nose), pharynx, and the larynx. The "lower respiratory tract" consists of the lower part of the respiratory system. This consists of the trachea (wind pipe), bronchial tubes, bronchioles, and lungs. The upper and lower respiratory tracts make up our whole respiratory system and work in a synchronizing pattern to make it possible to breathe.

17. Major Functions of the Respiratory System • To supply the body with oxygen and dispose of carbon dioxide • Respiration – four distinct processes must happen • Pulmonary ventilation – moving air into and out of the lungs • External respiration – gas exchange between the lungs and the blood

18. Major Functions of the Respiratory System • Transport – transport of oxygen and carbon dioxide between the lungs and tissues • Internal respiration – gas exchange between systemic blood vessels and tissues

19. The Nose • Composed of an external part • Composed of an internal part – nostrils and other features

20. Function of the Nose • The only externally visible part of the respiratory system that functions by: • Providing an airway for respiration • Moistening and warming the entering air • Filtering inspired air and cleaning it of foreign matter • Serving as a resonating chamber for speech • Housing the olfactory receptors

21. Structure of the Nose • Nose is divided into two regions: • External nose, including the root, bridge, dorsum nasi, and apex • Internal nasal cavity • Philtrum – a shallow vertical groove inferior to the apex • The external nares (nostrils) are bounded laterally by the alae

22. Structure of the Nose Figure 22.2a

23. Structure of the Nose Figure 22.2b

24. Figure 7.2a

25. Figure 7.10a

26. Internal Nose -- Nasal Cavity • Lies in and posterior to the external nose • Is divided by a midline nasal septum • Opens posteriorly into the nasal pharynx via internal nares • The ethmoid and sphenoid bones form the roof • The floor is formed by the hard and soft palates

27. Inside the Nose • 1. When first come into nose (Nasal Vestibule)– you have the skin of the nose – covered by a non-keratinized stratified squamous epithelium with plenty sweat and oil glands plus Vibrissae (Nose hairs) • 2. Come in further and find two types of mucous membranes Olfactory mucous membrane – smell area Respiratory mucous membrane – the other membrane

28. Respiratory mucous membrane • – covered by a ciliated pseudostratified columnar epithelium with plenty of goblet cells interspersed. The lamina propria had many blood vessels and serous and mucous glands plus lots of lymphatics and white blood cells.

31. Nasal Mucosae

32. Nasal Cavity • Vestibule – nasal cavity superior to the nares • Vibrissae – hairs that filter coarse particles from inspired air • Olfactory mucosa • Lines the superior nasal cavity • Contains smell receptors

33. Nasal Cavity • Respiratory mucosa • Lines the balance of the nasal cavity • Glands secrete mucus containing lysozyme and defensins to help destroy bacteria • Plasma cells that secrete IgE and IgA • Mast Cells and other WBC’s • Sneeze reflex areas • Swell Bodies • Kiesselbach’s Area - • Capillary and Venous Plexuses

34. Kiesselbach’s Area & Swell Bodies • Kiesselbach’s Area - a region in the anteroinferior part of the nasal septum, where four arteries anastomose to form a vascular plexus called Kiesselbach's plexus. usual site for epistaxis as it is exposed to drying effect of inspiratory current. Ninety percent of nose bleeds arise there. • Swell Bodies - The nasal swell body is a widened region of the septum located superior to the inferior turbinates and anterior to the middle turbinates, and of potential importance to the airflow-regulating nasal valve. Although little is known of this structure in terms of vasoreactivity and tendency to limit airflow by vascular engorgement, some consider the swell body to be physiologically analagous to the inferior turbinate.

36. Kiesselbach’s Area

37. Nasal Cavity • Inspired air is: • Humidified by the high water content in the nasal cavity • Warmed by rich plexuses of capillaries • Ciliated mucosal cells remove contaminated mucus

38. Nasal Cavity • Superior, medial, and inferior conchae: • Protrude medially from the lateral walls • Increase mucosal area • Enhance air turbulence and help filter air • Sensitive mucosa triggers sneezing when stimulated by irritating particles

39. Nasal Cavity Figure 22.3b

40. Figure 7.7

41. Functions of the Nasal Mucosa and Conchae • During inhalation the conchae and nasal mucosa: • Filter, heat, and moisten air • During exhalation these structures: • Reclaim heat and moisture • Minimize heat and moisture loss

42. Paranasal Sinuses • Sinuses in bones that surround the nasal cavity • Sinuses lighten the skull and help to warm and moisten the air

43. Figure 7.11

44. Pharynx • Funnel-shaped tube of skeletal muscle that connects to the: • Nasal cavity and mouth superiorly • Larynx and esophagus inferiorly • Extends from the base of the skull to the level of the sixth cervical vertebra

45. Pharynx • It is divided into three regions • Nasopharynx • Oropharynx • Laryngopharynx

46. Nasopharynx • Lies posterior to the nasal cavity, inferior to the sphenoid, and superior to the level of the soft palate • Strictly an air passageway • Lined with pseudostratified columnar epithelium • Four entrances in nasopharynx – two internal nares and two openings from the eustachian (auditory) tubes • Pharyngeal Tonsil – when enlarged is Adenoid

47. Figure 15.25a

48. Nasal Cavity Figure 22.3b

49. Lymphatics in Nasal and Oral Areas • Waldeyer's tonsillar ring is an anatomical term describing the lymphoid tissue ring located in the pharynx and to the back of the oral cavity. • It was named after the nineteenth century German anatomist Heinrich Wilhelm Gottfried von Waldeyer-Hartz. • The ring consists of (from superior to inferior): • Pharyngeal tonsil (also known as 'adenoids' when infected) • Tubal tonsils • Palatine tonsils (commonly called "the tonsils" in the vernacular, less commonly termed "faucial tonsils") • Lingual tonsils