Histology II Flashcards
What is the purpose of the nasal septum?
Breaks up air and causes turbulence upon inhalation, exposing more air to the surrounding epithelium for filtering and air conditioning
What are characteristics of Olfactory epithelium?
- Olfactory cells (bipolar neurons) - send signals to brain
- Non-motile cilia on olfacotry vesicle
- NO goblet cells
- Supporting cells
- Stem cells
- Thin basement membrane
- Bowmans glands
What are Bowman’s Glands?
Glands that release SEROUS secretion to moisten apical surface of olfactory epithelium and trap odiferous molecules to be sensed by bipolar olfactory neurons
How can you differentiate between false vocal cords and true vocal cords?
- *False Vocal cords (aka folds):**
- Surface is Pseudostratified Ciliated Columnar (PCC) epithelium
- Core has serous glands
- no striated muscle
- True vocal cords*:
- Surface is stratified squamous epithelium
- Core is skeletal (vocalis) muscle = allows for control and production of speech
- Has vocal ligament
What is the epithelium found in the trachea? Why?
Respiratory epithelium (aka Pseudostratified ciliated columnar epithelium)
- b/c no air exchange is being conducted in the trachea
What is the function of the trachealis muscle?
Aid in clearance during coughing
What are characteristics of the mucosal glands in the trachea?
There are both mucous and serous glands present
Mucosa also contains lymphoid aggregates
How is air flow conducted through the lungs (starting with trachea)?
Trachea –> Primary Bronchi –> Lobar bronchi –> Segmental bronchi –> smaller bronchi –> bronchioles –> terminal bronchioles –> Respiratory bronchiole –> alveoli
*Gas exchange begins with respiratory bronchiole
How can you differentiate between a bronchus and a bronchiole?
cartilage = bronchus
no cartilage = bronchiole
How does blood travel through the lungs?
- Blood is carried to lungs by pulmonary and bronciholar arteries
- Branches of both vessels travel with conducting airways
- Extensive plexus of capillaries exist in walls of alveoli for gas exchange
- venous drainage occurs at some distance from conducting airways and anastomoses into pulmonary veins
What are characteristics of “Respiratory” epithelium?
AKA: Pseudostratified Ciliated Columnar epithelium:
- “muco-ciliary escalator” = goblet cells, ciliated cells
Moves mucous and waste up the respiratory track - Basal (stem) cells
- Brush cells - sensory receptor cells
- Small granule cells - endocrine cells that modulate function of lung with hormones
*
What are some physical requirements that allow for gas exchange to occur?
- Large surface area
- Minimized distance for diffusion
- Maintain structural integrity of alveoli to minimize probability of lung collapse
- Match ventilation and blood flow
What is contained in the lumen of alveolus?
Air
Debris
Alveolar macrohpages (move along surface lining)
What cell types are found in alveoli?
- surface of alveolar lining epithelium is covered by surfactant
- Alveolar epithelium include:
- *Type I pneumocytes** (Squamous cells)
- *Type II pneumocytes** (larger cells, produce surfactant)
- Some Connective Tissue
- *Elastic Fibers** - between alveolar basal almina and endothelial basal lamina
- Endothelium of alveolar capillaries
What are characteristics of Type II pneumocytes?
- Secretes surfactant (stored in lamellar bodies)
- Matures late in pregnancy
- SP-A may play a role in inducing parturition (inducing labor)
