Histology: Respiratory System

Front 1

layers of tunica mucosa

Back 1

-innermost layer of tubular organ
1. l. epithelialis
2. l. propria
3. l. muscularis
-not all layers may be present

Front 2

propria submucosa

Back 2

l. propria + t. submucosa if l. muscularis absent

Front 3

layers of tubular organ

Back 3

innermost > outermost
1. tunica mucosa
2. tela submucosa
3. tunica muscularis
4. tunica serosa or tunica adventitia

Front 4

tunica adventitia

Back 4

blends with CT of adjacent organs or structures

Front 5

tela

Back 5

network

Front 6

external nose

Back 6

-keratinized st. squamous with pigmented cells
- characteristic grooves
- moist in ox and pigs by underlying glands, in dog by nasolacrimal gland overflow
-shape supported by internal cartilage

Front 7

vestibular region of nasal cavity

Back 7

-transition to non-keratinized mucosa
- serous or mixed glands in the underlying CT help humidify entering air

Front 8

respiratory epithelium

Back 8

-pseudostratified ciliated columnar epithelium with goblet cells
- some cells with microvilli
-humidify and cleanse air
- cilia pushes up mucous with particulate/ foreign body material inside

Front 9

nasal glands

Back 9

mixed glands which humidfy respiratory region

Front 10

erectile tissue of respiratory region

Back 10

-vascular cavities fill with blood and warm air of nasal cavity
-thermoregulation

Front 11

conchae (turbinates) of respiratory region

Back 11

-bony scrolls which extend off the lateral wall of the nasal cavity
-increase surface area

Front 12

olfactory epithelium

Back 12

-no goblet cells: whited out areas
-pseudostratified columnar epithelium
1. sustentacular cells
2. basal cells
3. olfactory cells

Front 13

sustentacular cells

Back 13

-of olfactory epithelium
- support
- uppermost layer of nuclei
- have microvilli

Front 14

basal cells

Back 14

-of olfactory epithelium
-basal cell layer of nuclei
- epithelial stem cell
-immature receptor cell?

Front 15

olfactory cells

Back 15

-of olfactory epithelium
- bipolar neurons
- non-motile cilia on olfactory bulb
- lifespan on cells about 50 days: turnover unique to these neurons
- adapt: shut down after a period of time with the same continuous odor

Front 16

olfactory cell numbers

Back 16

1. dog: 280 million, 7K square mm, can detect 1 x 10^13 (1 drop in 530, 000 barrels of water)
2. cat: 67 million, ? square mm
3. human: 20 million, 500 square mm

Front 17

olfactory (Bowman's) glands

Back 17

-serous glands
-in propria submucosa
- cleanse epithelial surface and solubilize odors

Front 18

paranasal sinuses

Back 18

-spaces in maxillary, frontal, ethmoid, and sphenoid bones
-continuous with nasal cavity
- epithelium ranges from squamous to this respiratory (few goblet cells)

Front 19

vomeronasal (Jacobson's) organ

Back 19

-paired tubular structure in the floor of the nasal cavity
-empties into incisive duct
- lined with respiratory (lat) and olfactory (med) epithelium
-chemoreception of liquid-bourne components
- associated with sexual behavior: Flehman reaction or lip curl

Front 20

nasopharynx

Back 20

-lined with respiratory epithelium
- diffuse and aggregated lymphatic tissue
- pharyngeal tonsil in roof of nasopharynx

Front 21

larynx

Back 21

-connects pharynx with trachea
-several cartilages present, joined by skeletal muscle and ligaments
- vocal fold extends from arytenoid to trough of thyroid
- lined with st. squamous resp epi: may have tastebuds on GI surface
-lymphatic tissue beneath epithelium

Front 22

cartilages of larynx

Back 22

1. epiglottis: elastic, often infiltrated with fat
2. thyroid, cricoid, paired arytenoid: hyaline
3. corniculated process of arytenoid is elastic

Front 23

trachea

Back 23

-cross section shape varies w species
-lined with repiratory epithelium
- submucosal glands: seromucous, provide most of tracheal secretions
- C shaped hyaline cartilage rings give support to walls
- smooth m between the open ends of the cartilage: trachealis m
- surrounded by t. adventitia

Front 24

lung

Back 24

-divided into lobes and lobules
- pattern is species variable
- covered by visceral pleura

Front 25

bronchus

Back 25

-branch from trachea
- lined w respiratory epithelium
- l. propria and l. muscularis mucosae spiraled
-cartilage in plate instead of rings

Front 26

bronchiole

Back 26

-lined with simple cuboidal or columnar epithelium
-no goblet cells at this level
-no cartilage
-muscle can contract and narrow airways

Front 27

bronchiolar cells (of bronchiole)

Back 27

-also called Clara or bronchiolar exocrine cells
- cuboidal, domed cells
- no cilia
- secrete glycoproteins and metabolize xenobiotics

Front 28

ciliated lining cells of bronchioles

Back 28

-cilia decrease as you progress down the airway

Front 29

neuroendocrine cells of bronchiole

Back 29

- role unclear

Front 30

respiratory bronchiole

Back 30

-first level of respiration
- lined with cuboidal cells
- alveoli protrude from the walls

Front 31

alveolar duct

Back 31

-connects respiratory bronchiole to alveolar sac
- small patches of smooth m

Front 32

alveolar sac

Back 32

a cluster of alveoli

Front 33

squamous alveolar epithelial cell type I

Back 33

-primary lining cell of alveolus
- simple squamous epithelium

Front 34

granular alveolar epithelial cells type II, great alveolar cell

Back 34

-secretory cell: produces surfactant
- round of cuboidal, projecting into lumen
- foamy cytoplasm
-lamellar bodies at EM level are precursors of surfactant

Front 35

pulmonary macrophages

Back 35

-septal macrophage stationary
- alveolar macrophage migrates

Front 36

septal pores

Back 36

present between alveoli

Front 37

blood supply

Back 37

1. pulmonary a: functional gas exchange
-forms an extensive capillary bed for gas exchange
2. bronchial a: nutritional

Front 38

septal space

Back 38

-space between the basal lamina of the alveolar epithelium and basal lamina of the capillary endothelium
-contains CT fibers, fibroblasts, macrophages, plasma cells, lymphocytes

Front 39

blood-air barrier

Back 39

1. alveolar lining cell
2. basal lamina of epithelium
3. basal lamina of endothelium
4. endothelial cell capillary