Respiratory System

Dr Iram Iqbal

11/13/09

1

The respiratory system consists of the paired lungs & a series of air passages that lead to & from the lungs

11/13/09

2

FUNCTIONS • Air conduction • Air filtration • Gas exchange • Olfaction • Phonation • Resonance • Regulation of immune response 11/13/09

3

The air passages of respiratory system consists of: of Conducting portion Respiratory portion

11/13/09

4

11/13/09

5

11/13/09

6

11/13/09

7

Conditioning of the air.... • Air passing through the respiratory passage must be conditioned before reaching the terminal respiratory unit. • Conditioning of the air occurs in the conducting portion of the system and includes. • Warming • Moistening • Removal of the particulate material. 11/13/09

8

DIVISIONS OF LUNG • Pulmonary lobule • Bronchopulmonary segment • Respiratory bronchiolar unit • Pulmonary acini

11/13/09

9

NASAL CAVITY • VESTIBULE • RESPIRATORY SEGMENT • OLFACTORY SEGMENT

11/13/09

10

VESTIBULE • Stratified squamous epithelium • Vibrissae • Sebaceous glands • Sweat glands • Where vestibule ends the Stratified squamous epithelium changes to pseudostratified epithelium that characterizes the respiratory segment. 11/13/09

11

RESPIRATORY SEGMENT

• Ciliated pseudostratified columnar epithelium • Epithelium has 5 type cells – – – – –

Ciliated cells Goblet cells Brush cells Small granule Basal cells

• Medial and lateral wall of nose – Role of turbinates

11/13/09

12

BRUSH CELL

11/13/09

SMALL GRANULE CELL 13

RESPIRATORY SEGMENT • Mucosa – Worm – Moisten – Filter air

• Lamina propria (attached to periosteum of adj bone)

• Swell bodies • Mucous glands 11/13/09

14

11/13/09

15

OLFACTORY SEGMENT • Olfactory mucosa – Yellow brown colour – Surface area a few sq cm

• Lamina propria – Adherent with periosteum – CT contain numerous blood vessels lymphatic vessels .unmyelinated olfactory nerves, myelinated nerves , & olfactory glands. 11/13/09

16

OLFACTORY SEGMENT • Olfactory Epi is • Pseudostratified epithelium but contain diff cell types • Lack goblet cells • Olfactory epithelium composed of 4 cell types • Olfactory cells • Supporting cells • Basal cells • Brush cells • Bowman’s glands

11/13/09

17

11/13/09

18

11/13/09

19

Olfactory cells • • • •

•

Spindle shaped, with round nuclei; (present in the middle and deep zone of the epithelium.) The apical part extends to the epithelial surface, ends in a bulbous knob which bears 6-8 olfactory hairs; These hairs or cilia are non-motile, sensory and serve as dendrons; They are embedded in a thick layer of mucus and parallel the surface of the olfactory epithelium. The proximal (basal) part of the cells form a long thin axonal process, which constitute the olfactory nerve fibers; these unmyelinated fibers are connected to the olfactory center of the brain (in the olfactory bulbs). Olfactory cells are modified bipolar neurons.

11/13/09

20

11/13/09

21

Supporting cells

Tall slender cells make up the upper third of the pseudostratified epithelium .Apical nuclei. • They are attached to the olfactory cells at the surface of the epithelium by zonula adherens • Have numerous mitochondria ,sER & small Golgi complex in the apical cytoplasm and pigment granules • There are numerous slender villi on their apical 22 surface.  •

11/13/09

Basal Cells&Brush Cells • Brush cells are same as present in other part of conducting system • Exhibit large blunt microvalli at their apical surface • Basal cells constitute a single layer of conical elements a the base of supporting cells (bottom layer of nuclei); have dark nuclei and branching processes. 

11/13/09

23

The venous plexus in Lamina propria• .the lamina propria is continuous with that of the respiratory regions. • A group of branched, tubuloalveolar (mainly serous) olfactory glands called Bowman's glands present in the lamina propria supply the necessary solvents to trap odoriferous substances. • The continuous replacement of secretion keeps the receptors ready for new stimuli.

11/13/09

24

PARANASAL SINUSES • RESPIRATORY EPITHELIUM • TYPES • Thin pseudo stratified columnar epithelium • Numerous Goblet cells

11/13/09

25

Larynx True vocal card function is phonation& conduction of air. False vocal card function is resonance.

11/13/09

26

The wall of the Larynx consists of : Mucosa . Epithelium -- varies according to wear and tear in the different regions of the larynx

Poorly defined submucosa A series of irregularly shaped cartilages connected by joints of relatively dense fibroelastic tissue. A group of intrinsic skeletal 11/13/09 muscles which act upon the

27

Luminal surface of vocal cords is covered with stratified squamous epithelium as most of the epiglottis. Rest of larynx is lined with the ciliated pseudo stratified columnar epithelium Connective tissue contain mixed mucoserous gland that secrete through ducts on to the laryngeal surface’ 11/13/09

28

11/13/09

• The false vocal cords - (located above the true vocal cords) are covered with pseudostratified, ciliated columnar epithelium with goblet cells. • The true vocal cords - are covered with moist stratified squamous 29 epithelium.

11/13/09

30

Lamina propria • Is rich in elastic fibers. In the true vocal cord there is an elastic band that constitutes the vocal ligament and it is adjacent and parallel to the vocal muscle in the deeper layers of the lamina propria.

11/13/09

31

• The glands in the larynx are tubuloacinar, mixed (sero-) mucous glands, they are absent from the avascular vocal cords.

11/13/09

• Cartilages -- support the walls of the larynx;They are united by ligaments and maintain the larynx as a constantly open tube. epiglottis and arytenoid cartilages become elastic • The larger cartilages remain hyalin (e.g., thyroid cart.)

32

The Epiglottis • It closes that laryngeal aperture like a lid, is covered by moist stratified squamous epithelium

11/13/09

33

11/13/09

Larynx, level 1. Sg: seromucinous glands at the base of the epiglottis.

34

Larynx, level 2. Vp: ventral pouch, A: processes of the arytenoid cartilages, U: u-shaped cartilage. 11/13/09

35

11/13/09

Larynx, level 3

C: cricoid cartilage 36

11/13/09

37

11/13/09

38

Short, flexible, air tube 2.5 cm in dia 10 cm long Extent(larynx to middle of thorux) Function (conduit&conditioning of air)

11/13/09

39

The Trachea • The trachea is supported by Cshaped cartilages, with the open part of the C facing the esophagus and it is bridged by fibro elastic tissue & smooth muscle the trachealis muscle Adjacent cartilages are connected by dense fibro-elastic membranes 11/13/09

40

Trachea

11/13/09

41

Tracheal epithelium is similar to respiratory epithelium in other parts of the conducting airway • Cell types in tracheal epithelium • Principal cells – Ciliated columnar cells – Mucous (goblet) cells – Basal cells

• Present in small numbers – Brush cells – Small granules cells 11/13/09

42

Tracheal epithelium

Basal bodies

11/13/09

43

11/13/09

44

•Extensive cytoplasm •Nucleus located near the BM •Membrane bounded dance core granules •Type 1secretion’ catecholamine •Type 2’ secretion calcitonine & serotonin gastrin releasing peptide

BRUSH CELL

•Columnar cell that bear blunt microvilli •The basal surface of the cell is in synaptic contact with an afferent nerve ending •The brush cell is regarded as a 11/13/09 receptor cell

SMALL GRANULE CELL 45

11/13/09

46

Wall of trachea consists of four definable layers

11/13/09

47

• Cell types • Thick basement membrane • Lamina propria containing BALT • Elastic membrane • Submucosa containing mixed glands • Tracheal cartilage and trachealis muscle • Adventitia

11/13/09

48

11/13/09

49

11/13/09

50

11/13/09

51

11/13/09

52

11/13/09

53

11/13/09

54

PLAN OF LUNGS

11/13/09

55

11/13/09

56

THE CONDUCTIVE DIVISION EXTRA PULMONARY BRONCHUS

11/13/09

57

BRONCHI

• MUCOSA – Pseudo stratified epithelium (height decreases) – Basement membrane thickness decreases – Lamina propria same but reduced in amount • MUSCULARIS • SUBMUCOSA – Relatively loose connective tissue – Glands – Adipose tissue in large bronchi • CARTILAGE LAYER – Discontinuous cartilage plates

• ADVENTITIA 11/13/09

58

11/13/09

59

INTRAPULMONARY BRONCHUS

11/13/09

60

11/13/09

61

Pulmonary acini • Pulmonary acini are the smaller unit of structure that make up the lobules .Each acinus consist of a terminal bronchiole and the reparatory bronchioles and alveoli. • Alveoli are the thin walled outpocketing • extending from the luman of the repiratory bronchioles. • Alveoli are the sites at which air leaves & enters the bronchioles to allow gass exchange.

11/13/09

62

Terminal bronchiole • TB represent the smallest passageways for conducting air . • Diameter 1mm or less • Lined by simple columnar....... Simple cuboidal. • Cartilage plates, bronchial glands, & goblet cells are absent. • Mucosal folds prominent (smooth muscle contraction) • Well developed smooth muscle layer surrounds thin lamina propria. • Adventia 11/13/09

63

11/13/09

64

11/13/09

65

THE RESPIRATORY DIVISION

11/13/09

66

BRONCHIOLES

constitute the transitional zone in the respiratory system. Involved in both air conducting & gass exchange.

11/13/09

67

11/13/09

68

11/13/09

69

11/13/09

70

11/13/09

71

11/13/09

72

11/13/09

73

11/13/09

74

11/13/09

75

CLARA CELL. Secrete a surface active agent luminal adhesion.) 11/13/09

(,prevent 76

11/13/09

77

11/13/09

78

THE PULMONARY ALVEOLI

11/13/09

79

ALVEOLAR DUCTS

• Are the branches (2 to 11) of respiratory bronchioles. These are thin walled tubules. Their wall is interrupted by the opening of many thin walled outpouchings, the alveoli. • Epithelium -- not distinguishable.. • Wall -- composed of strands of elastic and collagenous fibers, and a few smooth muscle cells which are visible around the mouth of alveolar sacs. 11/13/09

80

ALVEOLAR SACS • ALVEOLAR SACS -- are composed of 2 to 4 or more alveoli. • Alveolar sacs open only into the alveolar ducts. • The space into which alveolar sacs open in the alveolar duct is called the atrium.

11/13/09

81

THE ALVEOLUS • . THE ALVEOLUS -- is a thin walled polyhedral sac which opens on one side only into the alveolar sac or individually into an alveolar duct • Number(150-250million/adult lung) • Surface area(75mm) roughly the size of tennis court. • Diameter(.2mm) 11/13/09

82

11/13/09

83

11/13/09

84

THE ALVEOLUS • The alveolar epithelium is composed oftype l and type ll alveolar cells& occasional brush cells • The extremely thin squamous pulmonary epithelial cells (Type I pneumocytes);95% • Joined by occluding junction,,,,not capable of cell division

• The rounded great alveolar cells (Type II pneumocytes).5%, • Secretary cells,,,bulge into the air space,,,cytoplasm filled with

11/13/09

granules’’’

85

ALVEOLAR CELLS

11/13/09

86

11/13/09

87

Function • Type II pneumocytes secrete pulmonary surfactant . • The faulty production or absence of surfactant in newborns results in the fetal distress syndrome (hyalin membrane disease) • Ttpe ll are progenitorcells for type l • Type I pneumocytes function as lining cells of alveoli and thought to have the potential of differentiating into Type II pneumocytes.

11/13/09

88

11/13/09

89

11/13/09

90

11/13/09

91

Alveolar phagocytes • Pulmonary or lung macrophages, also known as dust cells. • a. Originate from blood borne monocytes; • b. Migrate into interstitium (C.T.) of lung and from there into the alveoli; • c. Similar to other macrophages; • d. Function in the removal of cell debris and foreign material (e.g. dust) from the lung. 11/13/09

92

ALVEOLAR MACROPHAGES (DUST CELLS)

11/13/09

93

BLOOD CIRCULATION OF LUNGS

11/13/09

94

LYMPHATICS OF LUNGS

11/13/09

95

11/13/09

96

11/13/09

97

REFERENCES Text & Atlas Of Histology By MICHAEL H. ROSS 5th Edition. BAILEY’S Textbook Of Microscopic Anatomy 18th Edition. Google search for images www.bu.edu/histology/i/10801hoa.jpg anatomy.iupui.edu/.../Respsystemf04/ty peII.jpg

11/13/09

98

11/13/09

99