Respiratory System

1. In the name of God Respiratory System Dr. zahiri

2. Respiratory system • comprising the lungs and a sequence of airways leading to the external environment • This system providing Oxygen and eliminating Carbon dioxide • is subdivided into: • conducting portions • respiratory portions

3. Conducting portion Parts: nasal cavity, nasopharynx, larynx, trachea, primary bronchi, secondary (lobar) bronchi, tertiary (segmental) bronchi, and terminal bronchioles functions : clean, warm and moisten air prior to reaching respiratory portion

5. Nasal cavity Nasal cavity composed of three regions( vestibule, respiratory and olfactory regions)

6. Vestibule Anterior portion of nasal cavity near of the nares dilated and known as the vestibule • lined with skin and has short, stiff hairs named vibrissae that prevent large dust particles to enter • dermis houses numerous sebaceous glands

9. Posterior aspect of Nasal cavity • lined by pseudostratified ciliated columnar epithelium (respiratory epithelium) • respiratory epithelium • Ciliated columnar cells: most common, each cell has about 300 cilia • Goblet cells: secret mucous • Brush cells: have short microvilli, nerve fibers, sensory function • Basal cells: are rounded stem cells that located near basal lamina and show mitotic figures • Small granule cells (kulchitsky cells= DNEs)

11. Subepithelial CT (lamina propria) • is richly vascularized, containing large arterial plexuses and venous sinuses, many seromucous glands and lymphoid elements

12. Olfactory region • the olfactory epithelium • lamina propria (serous secreting Bowman’s glands, a rich vascular plexus and many axons arising from olfactory cells of the olfactory epithelium)

13. olfactory epithelium comprises three types of cells: • Olfactory cells olfactory cells are bipolar neurons whose apical aspect (dendrite) is modified to form a bulb known as olfactory vesicle • Sustentacular cells • has a striated border composed of microvilli, and secretory granules • they provide physical support, nourishment • Basal cells • are short basophilic cells • their apical aspects do not reach the epithelial surface they proliferate and replace both two other cells

14. Paranasal sinuses Epithelium is respiratory similar to the epithelium of nasal cavity Lamina propriafused with periosteum of bones and houses seromucous gland and also lymphoid elements

15. Sinusitis • also known as a sinus infection or rhinosinusitis, is inflammation of the sinuses • Primary ciliary dyskinesia (PCD), also immotile ciliary syndrome or Kartagener syndrome, is a rare genetic disorder that causes defects in the action of cilia lining the respiratory tract (lower and upper, sinuses, Eustachian tube, middle ear) and fallopian tube

16. Squamousmetaplasia •  refers to benign non-cancerous change (metaplasia) of (non-squamous) surfacing lining cells (epithelium) to a squamous morphology

17. Metaplasia: an initial change from normal cells to a different cell type (such as chronic irritation of cigarette smoke causing ciliated pseudostratified epithelium to be replaced by squamous epithelium more able to withstand the insult).

18. Dysplasia: an increasing degree of disordered growth or maturation of the tissue . • Dysplasia is still a reversible process. • However, once the transformation to neoplasia has been made, the process is not reversible.

19. Anosmia • is the inability to perceive odor or a lack of functioning olfaction—the loss of the sense of smell.  • Anosmia may be temporary, but traumatic anosmia can be permanent.  • Anosmia is due to an inflammation of the nasal mucosa, blockage of nasal passages or a destruction of one temporal lobe.

20. nasopharynx • Epithelium is respiratory similar to the epithelium of nasal cavity • Lamina propria : pharyngeal tonsil

21. Larynx • connects pharynx to trachea • is lined by respiratory epithelium • Laryngeal cartilages(hyaline and elastic) are located in lamina propria • The cartilages connected to each other by ligaments and move with respect to one another by some striated muscles • Larynx has two folds consist of superior and inferior • Superior vestibular folds lined by respiratory epithelium • Inferior vocal folds lined by stratified squamous nonkeratinized epithelium

24. Laryngitis is an inflammation of the larynx. It causes hoarse voice or temporary complete loss of the voice because of irritation to the vocal folds(vocal cords).  • Dysphonia is the medical term for a vocal disorder, of which laryngitis is one cause. • croup

25. Epiglottis • is an elastic cartilage of larynx • It is lined by stratified squamous epithelium on lingual surface • Pseudostratified ciliated columnar epithelium lined the laryngeal side • Serous and mucous glands located in lamina propria

27. Trachea is a long tube that has 3 layers: mucosa, submucosa and adventitia Bifurcates into 2 primary bronchi

28. Trachea • Mucosa • Respiratory epithelium composed of 6 cell types located on a thick basement membrane • Goblet cells are about 30% of cells, produce mucinogen • Ciliated columnar cells about 30% of cells, are tall which have cilia and microvilli • Basal cells are also about 30% of cells, they are undifferentiated stem cells • Brush cells are just 3% of cells, they are narrow columnar cells that their function is unknown, but nerve ending associated with them • Serous cells are about 3% of cells, they are columnar and have serous granule • DNES cells, constitute about 3-4% of cells, have numerous granule in basal cytoplasm which is contain various pharmacological agents

29. Lamina propria composed of loose fibroelastic CT, contain seromucous glands and lyphoid elements, elastic lamina separate this layer from submucosa Submucosa Subnucosa is composed of dense irregular fibroelastic CT that houses mucous and seromucous glands, rich in blood and lymph supply Adventitia Adventitia is a fibroelastic CT that houses C-shaped hyaline cartilage, at posterior aspect of cartilage, there is a dense band of smooth muscle cells known as trachealis muscle

32. Bronchial Tree is composed of: • 2 primary bronchus that enter lungs • 3 lobar ( secondry) bronchus on right and 2 on the left • Segmental (tertiary) bronchus • bronchioles Terminal bronchioles Respiratory bronchioles Progressively airways decreased in size and cartilage, glands, goblet cells, and the height of epithelial cells But increase smooth muscle cells and elastic tissue

33. Primary Bronchi (Extrapulmonary) • Primary bronchi is identical to trachea, but have smaller diameter and thinner wall • Cartilage is in form of irregular plates • Smooth muscle located between lamina propria and submucosa as 2 distinct layers

36. Bronchioles • have not any cartilage or glands • but have few goblet cells • In larger bronchioles epithelium is simple columnar ciliated, with occasional goblet cells • In smaller bronchioles epithelium change to simple cuboidal, with no goblet cells • Bronchioles have a smooth muscle coats surrounded by fibroelastic connective tissue

37. Bronchioles Terminal bronchioles are terminus of conducting portion they are lined by cuboidal cells(some with cilia) and Clara cells which have domed apical surface Lamina propria is a fibroelastic CT, 1-2 layer of smooth muscle cells separate it from adventitia Clara cells ( exocrine bronchiolar cells) • Clara cells are columnar with dome-shaped apex • secretory granules • RER, which secret glycoproteins and surfactant-like materials • degrade toxins(SER) • divide to replace other cells • antimicrobial peptide

40. bronchiolitis • Bronchiolitis is inflammation of the bronchioles, the smallest air passages of the lungs. • Obliterative bronchiolitis

41. Asthma • (broncospasm) • Epinephrine

42. Respiratory Bronchioles • are a transitional zone between conducting and respiratory tissues • Alveoli branching from their walls • are lined by ciliated cuboidal epithelium with Clara cells that change to type I alveolar cells • Smooth muscle cells and elastic fibers underlie epithelium

44. Atelectasis • is defined as the collapse or closure of the lung resulting in reduced or absent gas exchange. • It may affect part or all of one lung.

45. Alveolar Ducts • do not have wall of their own • They are only a linear arrangements of alveoli • they end as a blind out pouching known as alveolar sac • Opening of alveolus to AD controlled by a single smooth muscle cell embedded

48. Diffuse alveolar damage • Adult respiratory distress syndrum • Cause: • bacterial & viral infection • Toxic gases • Excessive oxygen • fat embolism syndrume

49. Alveolus • Alveolus has 200 micrometer in diameter and is the functional unit of respiratory system • Open as out pouching from RB, AD • Composed of attenuated type I and type II pneumocytes • Connective tissue between them are very scant • Air space of two adjacent alveoli communicate through an alveolar pore • Interalveolar septum is between alveoli have an extensive capillary bed