Components of Respiratory System Flashcards
What are clara cells?
Cells in intrapulmonary portion of respiratory system which secrete surfactant instead of mucus + Clara cell protein
Clara cell protein is a marker found in bronchoalveolar fluid (reduced indicates lung damage) and serum (increased indicates leakage from air-blood barrier)
How can the respiratory system be divided?
CONDUCTING PORTION: Nasal cavity ———-> Terminal bronchioles
RESPIRATORY PORTION: Respiratory bronchioles —–> Alveoli
EXTRAPULMONARY: Nasal cavity ——————-> Primary bronchi
INTRAPULMONARY: Secondary bronchi ————> Alveoli
Outline the important structural and histological features of the nasal cavities.
NON-OLFACTORY:
- pseudostratified ciliated epithelium
- mucous glands + venous sinuses in lamina propria
- venous plexuses swell to alternate air flow from side to side (prevents overdrying)
- arterial blood flow warms inspired air
- surrounding cartilage/bone keeps patent
OLFACTORY:
- thick pseudostratified columnar epithelium (non-motile cilia, no goblet cells) in posterior-superior region of each nasal fossa
- olfactory cells (bipolar neurones) increase surface area & detect odours
- Bowman’s glands (serous) flush odours from the epithelial surface
- Lamina propria blends with submucosa
What are the important structural and histological features of the larynx?
Ventricular folds of larynx (above vocal folds) lined by pseudostratified epithelium, mucous glands, & lymph nodules (contributes to resonance of voice)
Vocal cords lined by stratified squamous epithelium (stop foreign objects from reaching the lungs & close to build up pressure during coughing):
- vocal ligament (bundle of elastic fibres)
- vocalis muscle (skeletal muscle)
What are the important structural & histological features of the trachea?
C-shaped cartilage ring + fibroelastic membrane + trachealis muscle
Epithelial & submucosal glands secrete: mucins, water, serum proteins, lysozymes, antiproteases (+ lymphocytes secrete IgA)
Fibrocartilaginous tube supported by U-shaped cartilages
Posterior gaps in cartilage covered by trachealis muscle (allows oesophagus to distend)
Divided into bronchi by the carina (sternal angle = T4/T5)
What is the common border of the oropharynx and the nasopharynx?
Cricoid cartilage
border between upper and lower respiratory tracts
Name all of the paranasal sinuses. Where does each one drain? Which has the highest risk of infection?
Frontal, ethmoid, maxillary, sphenoid
Posterior ethmoid & sphenoid drain into superior meatus
Others drain into middle meatus
Maxillary sinus has highest risk of infection (fills a lot before it drains)
What are the components of the larynx?
Unpaired cartilages: cricoid + thyroid + epiglottis
Suspended between hyoid bone and trachea via ligaments
Laryngeal prominence (Adam’s apple) on thyroid cartilage
+ ligaments (intrinsic & extrinsic) + muscles
Describe the functions of the larynx.
VENTILATION: abducted vocal cords
PHONATION: vibrating vocal cords (tension adjusted by vocalis & cricothyroid muscles) causes sound via abrasion (hence why the epithelium is stratified squamous)
SWALLOWING/COUGH REFLEX: epiglottis covers larynx, vocal cords adducted
What is the sternal angle? What level is it located at?
Manubriosternal joint
T4/T5
What does the term glottis mean?
2 vocal cords and the opening (aperture) between them
What are the inferior limits of the lung and pleura?
Mid-clavicular line:
- pleura: 8th rib
- lung: 6th rib
Anterior axillary line:
- pleura: 10th rib
- lung: 8th rib
Posterior (scapular line):
- pleura: 12th rib
- lung: 10th rib
At what levels are the horizontal fissure and oblique fissures of the lungs located?
Horizontal fissure (right lung only): along 4th rib from midaxillary line
Oblique fissure: spinous process of T2 to 6th costal cartilage
Why is a perforating wound of the lower intercostal spaces considered to be an abdominal wound as well as a thoracic wound?
Right dome of diaphragm reaches level of 5th rib during expiration
Left dome of diaphragm reaches level of 5th intercostal space during expiration
Therefore organs in the upper abdomen (liver, spleen, stomach, kidneys) can be damaged by a perforating thoracic wound of the lower intercostal spaces
When inserting a needle to drain a pleural effusion, what approach should be taken and why? What is this procedure called?
Superolateral approach (upper border of lower rib)
Avoids damaging intercostal artery, vein, and nerve (located just inferior to each rib)
Pleurocentesis (also known as thoracocentesis/pleural tap/pleural aspiration)
