Histologi Saluran Pernafasan

FYH - ERDS 2

• Divided into 2 principal regions :- conducting portion :

nasal cavity, nasopharynx, larynx, trachea, bronchi, bronchioles & terminal bronchioles

- rerspiratory portion :respiratory bronchioles, alveolar ducts, alveoli(alveoli : the greater part of the lung)

FYH - ERDS 3

RESPIRATORY EPITHELIUM• Ciliated Pseudostratified

Columnar Epithelium• 5 types of cell :

1. ciliated columnar epithelium2. mucous goblet cells3. brush cells4. basal cells5. small granule cells

FYH - ERDS 4

FYH - ERDS 5

NASAL CAVITY

• Consists of : - vestibule (external) - nasal fossae (internal)

VESTIBULE• Is the most anterior and dilated portion of nasal

cavity• Numerous sebaceous & sweat glands, vibrisae• Within the vestibule keratinized (-) respiratory

epithelium before entering the nasal fossae

FYH - ERDS 6

NASAL FOSSAE• Conchae :

- superior : specialized olfactory epithelium- middle respiratory - inferior epithelium

• The olfactory epithelium olfactory chemoreceptor located

• Ciliated Pseudostratified Columnar Epithelium

• 3 types of cells :1. supporting cells2. basal cells3. olfactory cells

Olfactory mucosa showing the 3 cell types (supporting, olfactory, and basal) and a Bowman’s gland.

FYH - ERDS 7

FYH - ERDS 8

PARANASAL SINUSES

• Closed cavities in the : frontal, maxillary, ethmoid, sphenoid bones

• Lined with a thinner respiratory epithelium, few goblet cells

• Communicate with nasal cavity through small openings

• Mucous product drain in to the nasal passages by ciliated epithelial cells

FYH - ERDS 9

NASOPHARYNX

• First part of the pharynx• Lined with respiratory epithelium

FYH - ERDS 10

LARYNX

• Connects the pharynx to the trachea• The larger cartilge : hyaline cartilage• The smaller cartilage : elastic cartilage• Cartilage participate in producing sounds for

phonation• Below the epiglottis : - false vocal sound

- true vocal sound

FYH - ERDS 11

TRACHEA

• Mucosa : - Ciliated Pseudostratified Columnar Epithelium with goblet cells- Lamina propria

• Sub mucosa : loose connective tissue• Hyaline cartilage : 16-20 C-shaped rings• Smooth muscle fibers• Adventisia (fibrosa)

FYH - ERDS 12

FYH - ERDS 13

FYH - ERDS 14

BRONCHUS• Ф ± 5 mm• Mucosa : similar to the mucosa of the trachea (Ciliated

Pseudostratified Columnar Epithelium)• The bronchial cartilage are more irregular shape• Larger bronchi : cartilage rings completely encircle the

lumen• Smaller bronchi : cartilage rings are replaced with

isolated plates or islands of hyaline cartilage• Lamina propria : smooth muscle layer, rich in elastic

fiber, abundance of mucous & serous gland ducts bronchial lumen

FYH - ERDS 15

PSEUDOSTRATIFIED COLUMNAR EPITHELIUM CARTILAGE MUSCULARIS ADIPOSE TISSUE

FYH - ERDS 16

BRONCHIOLES

• Ф ≤ 5 mm• Mucosa : - cartilage & glands (-)

- scattered goblet cells

TERMINAL BRONCHIOLESRESPIRATORY BRONCHIOLES

FYH - ERDS 17

FYH - ERDS 18

TERMINAL BRONCHIOLES

• Ciliated Pseudostratified Columnar Epithelium Ciliated Simple Columnar Epithelium Ciliated Simple Cuboidal Epithelium

• Clara cells : - (-) cilia- (+) secretory granules in their apex- secrete protein protect the bronchiolar lining against oxidative pollutants and inflamation- lamina propria : smooth muscle, elastic fiber

FYH - ERDS 19

Clara cells in the epithelium of a terminal bronchiole. These cells show secretory granules and a bulging apical cytoplasm. PT stain. High magnification.

FYH - ERDS 20

RESPIRATORY BRONCHIOLES

• Transition between conducting and respiratory • Mucosa : identical to the terminal bronchioles, except

their walls are interrupted by numerous sacklike alveoli proceeding distally alveoli »

• Ciliated Cuboidal Epithelium & Clara cells• Smooth muscle and elastic fiber

FYH - ERDS 21

Section of a terminal bronchiole with a small portion of a respiratory bronchiole continuous with an alveolar duct and many alveoli. PT stain. Low magnification.

FYH - ERDS 22

ALVEOLAR DUCTS• Proceeding distally the number of alveolar openings »

alveolar ducts• Alveolar duct & alveoli lined with squamous cells• Lamina propria : smooth muscle disappears at the distal

ends of alveolar ducts• Alveolar ducts atria that communicate with alveolar sacs• Elastic fiber : - enable the alveoli to expand

- contract passively with expiration• Reticular fibers :

- prevent overdistention- prevent damage to the delicate capillaries and thin

alveolar septa

FYH - ERDS 23

FYH - ERDS 24

ALVEOLUS

• Sacklike evaginations of the respiratory bronchioles, alveolar ducts, alveolar sacks

• Resemble small pockets that are open on one side similar to the honeycombs of a beehive

• Exchange of O2 and CO2 between air & blood• Each wall lies between 2 alveoli interalveolar septum• An interalveolar septum consists of 2 thin squamous

epithelial layers : - type I cells = squamous alveolar cells- type II cells = surfactant cells

FYH - ERDS 25

FYH - ERDS 26

TYPE I CELLS

• Line the alveolar surface• Cells are so thin (25nm)• Desmosomal & occluding junctions prevent

leackage of tissue fluid into alveolar air space• To provide a barrier minimal thickness that is readily

permeable to gases

FYH - ERDS 27

TYPE II CELLS

• Interspersed among the type I cells• Desmosomal and occluding junctions• Divided by mitosis replace type I & II pupolation• Exhibit a characteristic vesicular or foamy cytoplasm, by

presence of lamellar bodies• Lamellar bodies pulmomary surfactant alveolar

surface tension ↓ • Without surfactant alveoli collaps (expiration)• Surfactant appears in the last week of gestation

FYH - ERDS 28

Secretion of surfactant by a type II cell. Surfactant is a protein-lipid complex synthesized in the rough endoplasmic reticulum and Golgi complex and stored in the lamellar bodies. It is continuously secreted by means of exocytosis (arrows) and forms an overlying monomolecular film of lipid covering an underlying aqueous hypophase. Occluding junctions around the margins of the epithelial cells prevent leakage of tissue fluid into the alveolar lumen.

FYH - ERDS 29