1
Q
Conducting
vs
Respiratory Zone
A
- Conducting Zone
- Vestibule → Terminal bronchioles
- Warms and humidifies air
- Traps particles
- Produces sound
- Sense of smell
- Respiratory Zone
- Respiratory bronchioles → alveoli
- Gas exchange
2
Q
Nasal Cavity
Structure
A
- Nares ⇒ opening
- Vestibule ⇒ anterior most part
- Vibrissae ⇒ short thick hairs
- Conchae ⇒ shelf-like projections off septum
- Epithelia:
- Mostly lined with respiratory epithelium
- Transitional area ⇒ vestibule to respiratory region ⇒ minimally keritinized stratified squamous
- Olfactory epithelium
- roof of nasal cavity
- nasal septum
- superior nasal concha
- Thin lamina propria
- Numerous mucous glands
- Highly vascularized
3
Q
Olfactory Epithelium
A
- Pseudostratified columnar epithelium without goblet cells
- Taller than respiratory epithelium surrounding it
- 4 cell types:
- Olfactory receptor cells
- Sustentacular cells
- Brush cells
- Likely sensory function
- Same as those found in respiratory epithelium
- Basal cells
- Stem cells
- Lamina propria contains olfactory nerve bundles → cribriform plate of ethmoid → olfactory nerve
- Bowman’s glands
- Serous secretions
- Travels through ducts to surface
- Immunoglobulins provide protection
4
Q
Olfactory Receptor Cells
A
- Bipolar neurons
- Short apical dendritic processes bulges into an olfactory vesicle
- Non-motile cilia
- First 20% of each cilia with normal 9+2 microtubule arrangement
- Rest contains 11 single microtubules
- Basal end forms axons which travel into lamina propria
- Join to form nerve bundles → olfactory nerve
5
Q
Sustentactular Cells
A
- Numerous microvilli on apical surfaces
- Apical nuclei
- Contain lipofuscin granules
- Physical support to olfactory cells
- Secrete odorant-binding proteins (OBP)
6
Q
Olfaction
A
- Odorants bind to OBP in mucous
- Delivered to receptors on cilia of olfactory receptor cells
- Activates G-protein coupled receptors
- Odorants-OBP bind to various receptors with varying affinities
- Pattern sensed as particular smells
7
Q
Paranasal Sinuses
A
Frontal, ethmiodal, sphenoid, and maxilla.
- Hollows in bone surrounding nasal cavities
- Opens into nasal cavities
- Lined with respiratory epithelium
- Functions:
- resonance
- strengthening skull without additional weight
- crumple zone
- warm and humidify air
8
Q
Respiratory Epithelium
A
- Pseudostratified ciliated columnar epithelium containing goblet cells
- Found in:
- nasal cavities
- paranasal sinuses
- trachea
- bronchi
- larger bronchioles
- Contains 5 cell types:
- Ciliated cells
- Mucociliary escalator
- Goblet cells
- Produce mucous which coats epithelium
- Brush cells
- Likely sensory function
- Short microvilli
- DNES cells
- Endocrine cells secreting to lamina propria
- Catecholamines, calcitonin, gastin releasing peptide
- Do not reach epithelial surface
- Endocrine cells secreting to lamina propria
- Basal cells
- Stem cells
- Ciliated cells
9
Q
Pharynx
A
- Three regions:
- Nasal pharynx
- Mostly respiratory epithelium
- May be areas of olfactory epithelium
- Oral pharynx
- minimally keratinized stratified squamous
- Laryngeal pharynx
- minimally keratinized stratified squamous
- Nasal pharynx
- Passageway for air, liquid, and food
10
Q
Larynx
A
- Formed of elastic cartilage
- Connected by fibroelastic ligaments
- Moved by intrinsic and extrinsic skeletal muscles
- Functions to:
- seperate air from liquids/solids
- control aspects of breathing
- phonation
- Most lined with respiratory epithelium
- Except epiglottis and vocal folds covered with minimally keratinized stratified squamous
- Pharynx → Epiglottis → Larynx [Vestibule → Vestibular folds → Ventricle → Vocal folds] → Trachea
11
Q
Vestibular Folds
A
a.k.a. false vocal folds
- Structure:
- Respiratory epithelium over thick lamina propria
- Contain mucoserous glands
- Superior area → vestibule
- Inferior area → ventricle
- Seperates vestibular folds from vocal folds which lie below them
- Functions:
- Are not involved in sound production
- Affects resonance
- Role in controlling breathing
- Helps keep liquids/solids out of airway
12
Q
Vocal Folds
A
- Structure:
- Lie on either side of airway in anterior-posterior orientation
- Seperated by a space called the glottis
- Minimally keratinized stratified squamous
- Fibroelastic vocal ligament
- Located within the edge of the vocal fold
- Vocalis muscle
- Fills in the bulk of the vocal fold
- Intrinsic muscles
- Function:
- Involved in phonation
- Vocal folds vibrate as air forced through
- Intrinsic muscles alter vocal fold tension & glottis shape → controls pitch
- Vocal ligament and vocalis muscle also involved in sound production
13
Q
Trachea
A
- Runs inferior to larynx → hila of lungs
- Divides into right ahd left primary bronchi
- Four layers:
- Mucosa
- Respiratory epithelium
- Mucociliary escalator
- Thick basement membrane
- Lamina propria
- Cellular loose CT
- Rich in elastic fibers
- Contains lymphocytes
- Respiratory epithelium
- Submucosa
- Seperated from lamina propria by the elastic membrane
- Denser region of elastic fibers
- Similar in makeup to lamina propria
- Contains mucoserous submucosal glands
- secrete mucous into lumen
- Contains lymphocytes which can be aggregated into nodules
- Seperated from lamina propria by the elastic membrane
- Cartilage layer
- Contains C-rings
- Adventitia
- Outermost layer
- Due to location within mediastinum, is not covered with mesothelium
- Mucosa
- 16-20 C-shaped hyaline cartilages
- Cartilages interconnected to each other by fibroelastic CT
- Open ends of each C connected by trachealis muscle (smooth muscle) & fibroelastic CT
- Structure allows posteriorly located esophagus to expand into trachea during swallowing
14
Q
Bronchi
A
- Primary bronchi
- Tracheal bifurcation → hilum of lungs
- aka left and right bronchi
- Cartilages form rings
- Intrapulmonary bronchi
- Secondary bronchi and smaller
- Cartilage forms irregular plates
- Size decreases with each generation
- 11 generations until cartilages disappear → bronchioles
- Five layers in bronchi:
- Mucosa
- Respiratory epithelium
- Height of cells decreases as bronchi becomes smaller
- Basement membrane
- Becomes thinner
- Is no longer easily visible by LM at level of secondary bronchi
- Lamina propria
- Loose cellular CT with lymphocytes
- Respiratory epithelium
- Muscularis
- Smooth muscle layer between the lamina propria and submucosa
- Only in the intrapulmonary bronchi
- Forms complete ring in larger bronchi
- Becomes sparse in smaller tubes
- Submucosa
- Submucosal glands becomes sparse then dissappear in smaller bronchi
- Contains lymphocytes which can be aggreated into nodules
- Cartilage layer
- Plates arranged into cylindrical tube shape
- Adventitia
- Mucosa
https://www.proteinatlas.org/learn/dictionary/normal/bronchus+1
15
Q
Bronchioles
A
- Start at the 12th generation after cartilage disappears
- Respiratory epithelium in larger bronchioles
- Goblet cells present only in largest bronchioles
- Transitions to bronchiolar epithelium as height decreases
- Ciliated simple columnar
- Contains Club cells (Clara cells)
- Embedded in lung parenchyma
- Diameter controlled by state of lung expansion
- Terminal bronchioles
- smallest duct of the conducting zone
- bronchiolar epithelium
- Respiratory bronchioles
- start of the respiratory zone
- 3 generations with increasing ability for gas exchange
- lined in part by bronchiolar epithelium and in part by alveolar epithelium
- alveoli found at invertals which become more frequent with each generation
16
Q
Club Cells
A
a.k.a. Clara Cells
- Found in bronchiolar epithelium
- Domed cells which project above the epithelia
- Have microvilli
- Apical secretory granules secrete into lumen
- Produce protein components of surfactant → CC16
- Degrade toxins
- Act as stem cells for bronchiolar epithelium
17
Q
Alveolar Ducts
A
- Arise from respiratory bronchioles
- Tubular channels
- Walls made up almost entirely of alveoli
- Smooth muscle encircles opening to alveoli
18
Q
Alveolar Sacs
A
- Found along and at the ends of alveolar ducts
- Clusters of alveoli
- Mouth of alveolus associated with an alveolar sac usually encircled by a band of elastic fibers
- Opens into a common central space → atrium
19
Q
Alveoli
A
Terminal spaces of the respiratory system where gas exchange occurs.
- Composed of alveolar epithelium
- Contains 3 main cell types:
- Type I pneumocytes
- Type II pneumocytes
- Alveolar macrophages
- Few brush cells are scattered in alveolar epithelium
- Thought to be chemoreceptors for air components or particular matter
- Alveolar septum: alveolar epithelial layer closely approximated to capillary-containing layer
- In most places:
- Capillary sandwiched between two alveoli forming an interalveolar septum
- Basal laminae of Type I pneumocytes fuse with endothelial cell
- Makes air-blood barrier extremely thin
- In thick parts, CT comes between epithelium and capillary.
- Alveolar pores of Kohn:
- Small openings in interalveolar septa
- Allows passage of air from one alveolus to another
- Permits aeration of alveolus when supplying bronchiole blocked
- Helps equalize air pressure
20
Q
Type I Pneumocytes
A
- Covers ~ 95% of the alveolar surface
- Very thin cells
- Joined to one another and to type II cells by tight junctions
- Allows gas exchange
- Do not divide
21
Q
Type II Pneumocytes
A
- Cuboidal cells with rounded, bulging surfaces
- Almost as numerous as type I cells
- Covers ~ 5% of alveolar surface due to shape
- Produces surfactant
- Housed in lamellar bodies on apical surface
- Exocytosed into alveoli
- Composed of phospholipids (mainly DPPC) & surfactant proteins (A, B, C, D)
- Free surfaces with few short microvilli
- Stem cells for alveolar epithelium
22
Q
Air-blood Barrier
A
The minimal air-blood barrier consists of:
- surfactant layer
- type I alveolar cell
- fused basal laminae of type I cell and endothelial cell
- capillary endotheial cell
23
Q
Alveolar Macrophages
A
- Most numerous cell type in the lung
- Some found within interalveolar septum
- Most free in the surfactant layer within alveoli
- Phagocytize particles in the air and invading microorganisms
- Helps to make alveoli virtually sterile
- Up to 109 macrophages/day move via mucocilliary escalator and are spat out or swallowed
- Some leave via lymph or move into CT septa
- Macrophages that ingest carbon particles cannot break them down → if they remain in CT septa can color tissue
24
Q
Pulmonary Blood Supply
A
- Pulmonary arteries
- Carry deoxygenated blood from RV
- Braches follow intrasegmental bronchi → respiratory bronchioles
- Forms alveolar capillary network
- Continuous capillaries
- Located in the interalveolar septa
- Oxygenated blood → venules → veins
- Leaves lung at the hilum via pulmonary veins
- Pulmonary veins travel in CT septa separate from arteries
- Bronchial arteries
- Supply oxygenated blood to conducting zone
- Follows the airways
- Most drain into:
- alveolar capillaries
- directly into pulmonary veins
- Few true bronchial veins near hilum
25
Pulmonary Lymphatics
* **Deep lymphatic network**
* Begin near _alveolar ducts_
* Travels through CT towards hilum
* **Superifical lymphatic network**
* Located in _visceral pleura_
* Intrapulmonary lymph nodes located in the lungs
* Lymphatics pass through:
* **bronchopulmonary nodes** at hilum
* **tracheobronchial nodes** near tracheal bifuraction
* Leaves via **bronchomediastinal lymph trunk**
IMS: Microanatomy
flashcards
Decks in class (16)
# Cards
-
Integument35
-
Hypothalamus and pituitary43
-
Thyroid and Parathyroid22
-
Adrenal Glands21
-
Cartilage and Bone41
-
Bone Formation and Joints36
-
Blood87
-
Hematopoiesis42
-
Cardiovascular System39
-
Lymphoid Organs48
-
Respiratory System25
-
Oral Cavity and GI Track56
-
Liver, Gallbladder, Pancreas32
-
Urinary System35
-
Testis and Male Reproductive Tract52
-
Female Reproductive84
