1. Respiratory System Department of Histology and Embryology

2. Respiratory System Nasal cavity Nasal cavity The pharynx The pharynx The larynx The larynx The trachea, bronchi The trachea, bronchi The lung The lung

3. Respiratory System Conducting portion Conducting portion Respiratory portion Respiratory portion

4. Conducting portion Nasal cavity, nasopharynx, larynx, trachea, bronchi, bronchioles and terminal bronchioles Function: Condition the inspired air(cleaned,moistened, warmed)

5. Respiratory portion Respiratory bronchioles,alveolar duct, alveolar sac,and alveoli. Function:Gas exchange

7. Key points The structure of the trachea The structure of the trachea The composition and structure of respiratory portion The composition and structure of respiratory portion The function and structure of alveolus The function and structure of alveolus

8. vestibular region respiratory region olfactory region Nasal cavity Ep:stratified squamous ep.(Vibrissae) LP:sebaceous and sweat gland Ep: pseudostratified ciliated columnar ep. LP: vascular network Ep:olfactory ep. LP:serous gland(Bowman gland) Olfactory cells Supporting cells Basal cells

12. Trachea Structure: Structure: Mucosa: Mucosa: Submucosa Submucosa Adventitia Adventitia

13. Epithelium Pseudostratified ciliated columnar epithelium with much thicker basement membrane. Pseudostratified ciliated columnar epithelium with much thicker basement membrane. Ciliated cell Ciliated cell Goblet cell Goblet cell Brush cell Brush cell Basal cell Basal cell small granule cell small granule cell

14. Ciliated cell The most numerous of the tracheal cell types.They are tall columner cells with cilia which project from the apical surface. The most numerous of the tracheal cell types.They are tall columner cells with cilia which project from the apical surface. The cilia provide a coordinate sweeping motion from the farthest reaches towards larynx. The cilia provide a coordinate sweeping motion from the farthest reaches towards larynx.

15. Goblet cell Goblet cell They are interspersed among the ciliated cells.They can synthesize and secrete mucus. They are interspersed among the ciliated cells.They can synthesize and secrete mucus. The secretion covers the epithelium surface. The secretion covers the epithelium surface. Brush cell: they are columnar cells that bear blunt microvilli. Brush cell: they are columnar cells that bear blunt microvilli.

16. Basal cell: They serve as a reserve population that maintains cell replacement in the epithelium.It is stem cell. Basal cell: They serve as a reserve population that maintains cell replacement in the epithelium.It is stem cell. Small granule cell : They are difficult to distinguish from basal cells in the light microscope.With the TEM,the cytoplasm contains many granules. Small granule cell : They are difficult to distinguish from basal cells in the light microscope.With the TEM,the cytoplasm contains many granules.

18. Submucosa LCT containing mixed glands. LCT containing mixed glands. Serous glands that keep the epithelium moist;and mucous glands that provide a covering in which dust particles get caught. Serous glands that keep the epithelium moist;and mucous glands that provide a covering in which dust particles get caught. The mucous is continuously moved towards the larynx by cilia action. The mucous is continuously moved towards the larynx by cilia action.

19. Adventitia LCT containing "C" shaped hyaline cartilage and smooth muscles. LCT containing "C" shaped hyaline cartilage and smooth muscles. Hyaline cartilage provides a supporting structure that prevent collapse of the tracheal lumen during expiration. Hyaline cartilage provides a supporting structure that prevent collapse of the tracheal lumen during expiration. The gaps between the cartilages ends are filled in by smooth muscles. The gaps between the cartilages ends are filled in by smooth muscles.

21. Asthma Asthma is a serious disease that affects the lungs and the airways that deliver air to the lungs. Asthma is a serious disease that affects the lungs and the airways that deliver air to the lungs.

22. Allergy is the leading cause of asthma. It causes periodic attacks of wheezing and difficult breathing. An asthma attack occurs such as dust, pollen, pets, or cold weather.. The airways may become blocked when the muscles surrounding the lungs tighten. Or, mucus may narrow the airways in the lungs, making breathing even more difficult. Allergy is the leading cause of asthma. It causes periodic attacks of wheezing and difficult breathing. An asthma attack occurs such as dust, pollen, pets, or cold weather.. The airways may become blocked when the muscles surrounding the lungs tighten. Or, mucus may narrow the airways in the lungs, making breathing even more difficult.

23. Lung Parenchyma Bronchial tree Alveolus Mesenchyme:CT

25. Changes of conduction portion The cartilages become irregular,and are progessively smaller. Cartilages is absent in the bronchioles. The cartilages become irregular,and are progessively smaller. Cartilages is absent in the bronchioles. The amount of muscle in the bronchial wall increase. The amount of muscle in the bronchial wall increase. Glands become fewer,and are absent in the bronchioles. Glands become fewer,and are absent in the bronchioles. The epithelium become thiner. The epithelium become thiner.

27. Clara cells Terminal bronchiole lined by simple ciliated columnar cells. Cells that are found among ciliated columnar cells, are non-ciliated and contain rich secretory granules. Function:Protection against harmful substance; Stem cell function. Stem cell function.

31. Respiratory portion Function: Capable of air exchange. Respiratory bronchiole: the wall is populated with more and more alveoli. Respiratory bronchiole: the wall is populated with more and more alveoli. Alveolar duct:They have almost no walls,only alveoli,as their boundary. Alveolar duct:They have almost no walls,only alveoli,as their boundary.

32. Alveolar sac: They shared opening of several surrounding alveoli. Alveolar sac: They shared opening of several surrounding alveoli. Alveoli: Terminal blind ends of the track. The main place where the air exchanges occur. Alveoli: Terminal blind ends of the track. The main place where the air exchanges occur.

33. Respiratory bronchiole Alveolar duct Alveolar sac Alveoli

34. Alveoli Epithelium type I cells: squamous, cover 95% of the alveolar surface. type I cells: squamous, cover 95% of the alveolar surface. type II cells : Secrotory cells. contain multilamellar bodies, which are capable to release the surfactant to lower the surface tension. A surfactant is briefly defined as a material that can greatly reduce the surface tension. type II cells : Secrotory cells. contain multilamellar bodies, which are capable to release the surfactant to lower the surface tension. A surfactant is briefly defined as a material that can greatly reduce the surface tension. Can differentiate into Type I cells. Can differentiate into Type I cells.

35. Epithelium of Alveoli Epithelium of Alveoli Type Ⅰ alveolar cell Type Ⅱ alveolar cell

38. 2. Alveolar septum: Thin layer of LCT between adjacent alveoli. 2. Alveolar septum: Thin layer of LCT between adjacent alveoli. Continuous Caps: The richest Cap network in the body. Continuous Caps: The richest Cap network in the body. Abundant elastic and reticular fibers: Function when alveoli are enlarged. Abundant elastic and reticular fibers: Function when alveoli are enlarged. 3. Alveolar pores: Windows between the adjacent alveoli that can equalize the air pressure. 3. Alveolar pores: Windows between the adjacent alveoli that can equalize the air pressure. 4.Blood-air barrier 4.Blood-air barrier

40. Elastic fiber

41. Emphysema causes a loss of elasticity in the walls of the small air sacs in your lungs. When emphysema is advanced, you must work so hard to expel air from your lungs. Unfortunately, because emphysema develops gradually over many years, you may not experience symptoms such as shortness of breath until irreversible damage has already occurred. Treatments focus on relieving symptoms. causes a loss of elasticity in the walls of the small air sacs in your lungs. When emphysema is advanced, you must work so hard to expel air from your lungs. Unfortunately, because emphysema develops gradually over many years, you may not experience symptoms such as shortness of breath until irreversible damage has already occurred. Treatments focus on relieving symptoms.

42. 4.Blood-air barrier surfactant,type I cells and basal lamina, LCT, capillary endothelium and basal lamina surfactant,type I cells and basal lamina, LCT, capillary endothelium and basal lamina

43. Alveolar macrophages:

44. Review Test 1. Which of the following statements concerning terminal bronchioles is TRUE? 1. Which of the following statements concerning terminal bronchioles is TRUE? (A) They are part of the conducting portion of the respiratory system (A) They are part of the conducting portion of the respiratory system (B) They function in gas exchange (B) They function in gas exchange (C) They do not contain ciliated cells (C) They do not contain ciliated cells (D) They have cartilage plates present in their walls (D) They have cartilage plates present in their walls 2. Alveoli in alveolar sacs possess all of the following components EXCEPT? 2. Alveoli in alveolar sacs possess all of the following components EXCEPT? (A) elastic fibers in their walls (A) elastic fibers in their walls (B) a simple squamous lining epithelium (B) a simple squamous lining epithelium (C) reticular fibers in their walls (C) reticular fibers in their walls (D) smooth muscle in their walls (D) smooth muscle in their walls

45. Homework Describe the structure of the trachea Describe the structure of the trachea Compare the structure and function of olfactory epithelium with that of respiratory epithelium. Compare the structure and function of olfactory epithelium with that of respiratory epithelium. The composition of respiratory portion The composition of respiratory portion The structure of the alveoli. The structure of the alveoli.