Histo - Respiratory Flashcards
What are the 3 features of the Respiratory System?
- Conducting portion
- Respiratory portion
- Ventilating mechanism
What are the major components of the Conducting Portion?
Components:
- Nasal cavity
- Nasopharynx
- Larynx
- Trachea
- Bronchi/reg Bronchioles/terminal bronchioles
Features:
- Most have respiratory epithelium
- Specialized epithelium = olfactory epithelium
- At bronchioles:
- changes –> simple columnar w/ cilia
- then changes –> simple cuboidal w/ cilia
What are the features of Nasal Cavities?
Basics:
- Nares = stratified squamous keratinized (SSK)
- Vestibule = stratified squamous NOT keratinized (SSNK)
- Respiratory portion = respiratory epithelium
Conchae:
- superior, middle, inferior parts
Note:
- Roof of nasal cavity + superior conchae = lined by olfactory epithelium
What are the features of Paranasal Sinuses?
Basics:
- in the frontal, maxillary, ethmoid & sphenoiod bones
- lined by respiratory epithelium
- Lamina propria = continuous w/ periosteum
Function:
- communicate w/ nasal cavities
When things go wrong…
-
Sinusitis
- chronic inflammation of sinuses
- chronic congestion
What are the 5 major cell types of respiratory epithelium?
- Ciliated columnar cells
- Goblet cells
-
Brush cells
- sparse microvilli (hard to see)
- chemosensory receptors
- synaptic contact w/ afferent nerve endings on basal surface
- dont all reach surface
-
Small granule cells
- dense core granules
- enteroendocrine cells (APUD; DNES)
- secrete into blood supply directly
-
Basal cells
- stem cells for respiratory
What are the 3 major cell types (and APUD cells) in olfactory epithelium?
-
Olfactory neurons
- bipolar neurons
- apical part of dendrite
- cilia projecting from basal bodies
- cilia = NONmotile
- chemoreceptors
- axons = form fila olfactoria
- can regenerate from stem cells
- (can regain sense of smell)
- Supporting cells
- Basal Cells
4. APUD
- amine uptake and decarboxyation - enteroendocrine cells
- secrete directly into blood supply
Respiratory vs. Olfactory Epithelium
Respiratory
- thinner
- goblet cells
- regular cilia (motile)
- location = conducting portion
Olfactory
- thicker
- NO goblet cells
- regular + immotile cilia
- location = superior conchae
What are the 2 major components of the Olfactory Region?
- Olfactory epithelium
-
Lamina propria
-
Bowman’s glands
- serous secretion
- fluid
- helps w/ smell
-
Swell bodies
- veins
-
Fila olfactoria
- __nerves
-
Bowman’s glands
What are the components of the olfactory region that can be seen in this image?
What are the 2 major components of the Respiratory Passages?
-
Nasopharynx
- posterior to nasal cavity
- respiratory epithelium
-
Oropharynx
- throat
- caudal to nasophyarnx
- pharyngeal tonsil
- opening of Eustachian tubes
- SSNK
- elastic limiting layer (seen in image)
What can be seen in this image?
Larynx
- btw pharynx & trachea
Epiglottis
- prevents food from entering larynx
Vestibular folds (VF)
- respiratory epithelium
Vocal folds (VC)
- SSNK
- Phonation
- moved by vocalis muscle (VM)
What are the characteristics of the trachea & bronchi in the conducting portion of the respiratory system?
Trachea:
- C-shaped hyaline cartilage rings
- Trachealis muscle & fibroelastic tissue
- interact w/ edges of rings
Bronchi: (branches off of Trachea)
-
Extrapulmonary bronchi
- cartilage plates
- NO lung parechyma surrounding
-
Intrapulmonary bronchi
- cartilage plates
- lung parenchyma surrounding
Note:
- bronchi = cartilage
- bronchioles = NO cartilage
What structures are seen in this image?
Trachea
- C-shaped cartilage
- Trachealis muscles & fibroelastic tissue
What is in this image?
Extrapulmonary bronchi
- plate of hyaline cartilage
- has fat + CT ouside of it
Note:
- can see nearby lymphnode
What is in this image?
Intrapulmonary bronchi:
- overlapping cartilage
- respiratory epithelium
- nearby lung tissue/alveoli
What is this?
Bronchial Wall
- cartilage = deep to epithelium
- smooth muscle
- bronchi = scalloped
- mostly columnar respiratory epithelium
What are the characteristics of bronchioles?
Basics:
- NO cartilage
- Start of mucocilliary apparatus
Conducting portion:
-
regular bronchioles
- pseudostratified –> simple columnar ciliated epithelium
-
terminal bronchioles
- simple cuboidal ciliated epithelium
- 1-2 layer of smooth muscle
- END of conducting portion
- simple cuboidal ciliated epithelium
-
club cells (aka bronchiolar exocrine cells)
- non-ciliated/dome shaped
-
secrete:
- surfactant + antimicrobial products + IgA
- stem cells for bronchiolar eputhelium
- lose cartilage & glands
-
lamina propria
- w/ smooth muscle & elastic fibers
-
elastic fibers INCREASE
- towards alveoli
Respiratory Portion:
-
respiratory bronchioles
- simple cuboidal or simple squamous
- where gas exchange happens
- alveoi
- may have club cells
- simple cuboidal or simple squamous
What is the Air Exchange Portion of Lung?
Terminal bronchioles divide —> respiratory bronchioles (RB)
- respiratory bronchioles have alveoli coming off of them
- avleoli - mostly simple squamous lining
- wall looks discontinous, but still has simple cuboidal lining + club cells
Respiratory bronchioles –> continuous w/ alveolar ducts
- alveolar ducts (AD) = NO simple cuboidal lining
- have alveoli & knobs of smooth muscle
- continuous w/ alveolar sacs (AS)
- NO smooth muscle/knobs
- have lamina propria (CT) + elastic/reticular fibers
Alveoli (A) –> site of gas exchange
- have lamina propria (CT) + elastic/reticular fibers
What are the Cells in the Alveolus?
Pneumocytes
-
Type I:
- squamous
- air exhange
- 40% cells
- MOST surface area
-
Type II:
- in angles
-
lamellar bodies
- surfactant gets washed away in LM
- secrete surfactant
- 60% cells
- Stem cells for both type I & II
Non‐Pneumocytes
-
Endothelial cells
- angiotension-converting enzyme (ACE)
- Interstitial fibroblasts (aka septal cells)
- Macrophages (aka dust cells)
- Mast cells
- Blood cells
What can we see in this image?
What is this?
Type II Pneumocyte
Function:
- Makes surfactant
- reduces surface tension
- takes less respiratory force to inflate
- Stem cells for type I & II pneumocytes
What are the Blood‐air Barrier Components?
- Type I pneumocyte cytoplasm
- Basal lamina of type I pneumocyte
- Basal lamina of an endothelial cell
- Cytoplasm of endothelial cell
What is this?
Ultrastructure of the Blood‐Air Barrier
What is this?
Alveolar Macrophages (aka Dust Cells)
Basics:
- present in interstitum
- can be present in alveolar space
Function:
- Phagocytose worn out RBCs & particulates
- Can fill w/ material
- hemosiderin
-
Heart failure cells
- called this during CHF
- lungs congested w/ blood
- RBC pass into air space & are phagocytized
- called this during CHF
