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
What is Pleura?
Basics:
- Serosa associated w/ each lung + thoracic cavity
Parietal Pleura
- attached to inner surface of thoracic cavity
Viceral Pleura
- attached to outer surface of lung
Note:
- BOTH = meothelium w/ some CT
- In between BOTH = pleural cavity
- Will NOT see histologically
What is happening in this image?
(a) The diagram shows this branching relationship, as well as the pulmonary blood vessels that travel with the bronchioles and the dense layer of branching capillaries and elastic fibers that surround each alveolus.
(b) The micrograph shows the branching nature of the air passages in two dimensions: respiratory bronchiole (RB), alveolar ducts (AD), alveolar sacs (AS), and individual alveoli (A).
(c) SEM shows in three dimensions the relationship of a terminal bronchiole (TB), respiratory bronchiole (RB), alveolar duct (AD), alveolar sacs (AS), and individual alveoli (A).
