L26. Respiratory Tract Flashcards
What is the general organization of the internal tube based organ ( start from the outer layer)
- adventitia
- sub-mucosa
- mucosa
- -lamina propria
- -epithelium - lumen
Where is the epithelium layer of the mucosa derived?
endodermally derived
Describe the lamina propria layer in the mucosa layer
contains loose CT with MALT
Describe the sub-mucosa layer
- connective tissue
- glands
Describe the adventitia layer
-CT may contain muscles, bones and cartilage (depends on function and location)
State the conducting path of the respiratory system
nasal cavity->pharynx->larynx->trachea-> primary bronchi-> secondary bronchi ->tertiary bronchi -> primary bronchioles -> secondary bronchioles
Describe the trachea
- single tube
- lumen lined with hyaline cartilage
- lumen is always open
- major conducting airway in neck and thorax
- seromuccillary clearance of debris from the lumen
How is the diameter of the lumen regulated?
- smooth muscles causes lumen to contract
2. elastic connective tissue facilitates reopening of the tissue when the smooth muscle relaxes
Label all structures on pg 4b of L 26
pg 4b
Describe the inner layer (mucosa) of the trachea
- respiratory eptithelium
- pseudo-stratified epithelium
- ciliated
- contains loose connective tissue-epithelium
- contains MALT
- elastic lamina
- contains the following 4 cells
What is the function of the elastic lamina in the mucosa layer of the trachea
needed for recoil between the mucosa and he sub-mucosa
What are the 4 cells in the pseudostratified layer of the trachea and what are their functions
- columnar cells: contains apical motile cilia (microtubule based) required for seromucocilary clearance, beat upwards towards the pharynx
- goblet cells: apical secretes mucous. unicellular exocrine gland. has some apical non-motile microvili (actin based)
- small mucous granule cells : secretes paracrine factors basally; some secretions regulate muscle contraction (lumen diameter)
- basal stem cells
Describe the submucosa layer
fibroelastic connective tissue
seromucosa gland
complex acinar
has mucous acini releases carbohydrate/viscous secretion
contains serous demilune (protein/water secretion): consistency requires ion transport
Describe the adventitia layer
contains hyaline cartilage rings with smooth muscle which connects rings posteriorly
What system is the small mucous granule cells part of
diffuse neuroendocrine system
what does the small mucous granule cells respond to
low O2 levels have neural functions
Describe the pharynx and the 4 layers of it
- funnel shape , allows food and air to pass
- muscular not cartilaganous walls
- epithelium: stratified squamous due to friction from food, has some respiratory epithelium
- lamina propria: large MALT aggregates (tonsils)
- submucosa: has seromucuos glands ( ducts empty into lumen surface)
- adventitia: contains skeletal muscles needed for voluntary swallowing
Where is the larynx
between the trachea and the pharynx
What is the roof of the larynx and what is it’s function
epiglottis, closes during swallowing and opens during breathing. therefore made of elastic cartilage in the adventitia for flexibility
What is the floor of the larynx and what is it’s function
vocal folds, have submucosa and mucosa layer forming bilateral folds into the lumen.
describe the epithelium layer of the larynx
mostly pseudostratified ciliated columnara epithelium while the areas near the vocal folds and the epiglotis are stratified squamous because of the increased friction between the 2 epithelial against each other .vocal folds are sometimes keratinized
Describe the lamina propria of the larynx
loose connective tissue with some elastic fibers
Describe the submucosa of the larynx
CT with some seromucos gland, the vocal cords have a dense connective tissue (vocal ligament)
Describe the adventia layer of the larynx
has eleastic cartilage in the epiglottis
skeletal muscles are attached to the vocal ligaments, when the muscles contract the tension of the vocal cords increases and they vibrate to produce sound waves
Describe the nasal cavity
- muscocilary clearance
- lamina propria is highly vascular to keep cavity warm
- almost no submucosa layer
- cilia beats back to the pharynx
- prominent adventitia, hyaline cartilage anteriorly and bone posteriorly
- continuous with paranasal sinuses
What is a paranasal sinus
restricted spaces that cannot expand, especially the narrow passageway between the nasal cavities and the paranasal sinuses can become plugged due to inflammation in the lamina propria
Describe the epithelium of the nasal cavity
- pseudostratified
- ciliated
- contains goblet cells
- respiratory cells except anteriorly where it merges with the epidermis of the skin (stratified squamous)– near nostrils
Describe the lamina propria of the nasal cavity
- loose CT
- contains mucous glands
- contains some MALT
- highly vascular to keep nasal cavities war,
Describe the adventitia layer
- contains hyaline cartilage anteriorly and bone posteriorly
what is the roof of the nasal cavity
olfactory epithelium; modified respiratoty epithelium
Describe the olfactory epithelium
contains olfactory cells (=sensory neurons).
dendrites end in the modified sensory cilia which are embedded in odorant-containing serous secretions
-contain basal stem cells and supportive columnar cells
Describe the olfactory lamina propria
- has Bowman’s glands that open up on epithelial surface
- watery secretions trap the chemical particles that can stimulate the sensory dendrites of the olfactory cells
- above causes a modified action potential = smell
