Respiratory System II Flashcards
What is the conducting portion of the respiratory system?
“Series of tubes and cavities that carry air to and from the site of gas exchange”
Air goes from the nasal cavity where turbulant air is warmed, humidified, and filtered to the pharynx. Air travels town the muscular pharyngeal tube to enter the cartilaginous larynx which is superior to the trachea. The trachea is a series of cartilagenous rings that bifurcates into two main bronchi to eventually reach the bronchioles and alveoli where gas exhange occurs.
What is the purpose of the nasal cavity and paranasal sinuses?
- Filter, humidify, and warm air (venous plexus superior) entering the body
- Lined with pseudostratified ciliated epithelium with goblet cells/seromucous glands
- Superior, middle, and inferior conchae create turbulence to help warm/moisten the air
- Very little is known of the function of the paranasal sinus’
What are the three parts of the pharynx (superior to inferior)?
nasopharynx, oropharynx, and laryngopharynx
Where is the location and function of the larynx?
-Anterior neck, mostly cartilaginous held together by ligaments and membranes where the laryngeal muscles function to protect the lower respiratory tract, phonation and the cough reflex
Supraglottis -> from inferior epiglottis to the vestibular folds (false vocal cords)
Glottis -> Contains vocal cords and 1cm below is the opening of the vocal cords (rima glottidis)
Subglottis -> inferior border of glottis to the inferior border of cricoid cartilage (infraglottic)
What is the main function of the epiglottis?
- Seal off the larynx (windpipe) during eating, so that food is not accidentally inhaled (aspirated)
- Leaf shaped, located behind the tongue at the top of the pharynx
What are the three unpaired, and paired laryngeal cartilages?
Unpaired -> epiglottis, thyroid, and cricoid cartilages
Paired -> arytenoid, corniculate, and cuneiform
What is the innervation and blood supply to the larynx?
-Innervated by branches of the vagus nerve:
Recurrent laryngeal nerve -> sensory innervation to sub(infra)glottis, and motor innervation to all the internal muscles of larynx (except the cricothyroid)
Superior laryngeal nerve -> internal branch sensory innervation to supraglottis, and external branch motor innervation to cricothyroid muscle (tenses the vocal cord/fold)
-Blood supply is from the superior/inferior laryngeal arteries
What are the clinical symptoms of vocal cord paralysis?
-The recurrent laryngeal nerve can be damaged by lung tumor, thyroid cancer, or aortic aneurysm
Unilateral RLN palsy -> One vocal cord paralyzed, other compensates, speech not affected a lot but hoarseness of voice can occur
Bilateral RLN palsy -> Breathing and phonation impaired, if both cords are paralyzed surgical intervention is required to restore the airway
What is the bifurcation of the trachea called?
Carina
Explain the mechanism behind the cough reflex
- ~2.5L air is inspired
- Epiglottis closes, vocal cords shut
- Abdominal muscles and intercostal muscles contract, and push against the diaphragm
- Pressure in lungs rises to >100mmHg, the increased pressure narrows trachea
- Vocal cords and epiglottis suddenly open widely
- Air is expelled ~75-100 miles/hr
What are the main differences between the left and right mainstem bronchi?
Right -> 2-3cm long branch arising from fork of trachea, wider and more vertical so aspirated items usually end up there
Left -> about 5cm long, narrower and more horizontal
What week of development does the respiratory and laryngeotracheal diverticulum appear?
Weeks 4-6
Week 4: Right and left primary bronchial bud = (right and left lungs)
Week 5: Secondary or lobar branch = (number of lobes)
Week 6: Tertiary bronchi form
Right lung = 3 lobes
Left lung = 2 lobes
What seperates the right and left lungs?
- Heart and great vessels, the middle mediastinum
- Both contained in thier own pleural sacs
- Deflate to 1/3 of size when thoracic cavity is open (elastic fivers in alveoli)
Right or left lung?
Right lung -> Larger, heavier, wider, and shorter
Oblique fissure between sup. or middle and inf.
Horizontal fissure between sup. and middle
Right or left lung?
Left lung -> Usually just two lobes (can have three) seperated by oblique fissure
2 unique features:
- Cardiac notch
- Lingula (analagous to middle lobe of right lung)
Root of the lung refers to what
Refers to the structures contained in the pulmonary sleeve and entering the hilum of the lung:
Pulmonary arteries = Superior
Main bronchi = Posterior
Pulmonary veins = 1 anterior, 1 inferior
The hilum of the lung refers to what
“Doorway” and the area where the structures forming the root of the lung actually touch lung tissue
What structures leave impressions on the right lung?
Azygous vein
Right brachiocephalic vein
Superior vena cava
Esophagus
Heart or cardiac impression
What structures leave impression of the left lung?
Esophagus
Thoracic aorta
Left subclavian artery
Heart
Explain the bronchial tree
Branching system of air tuves in each lung, from main bronchus to 65K bronchioles
Right and left main bronchus -> Lobar (secondary) bronchi -> Segmental (tertiary) bronchi
What is different about the anatomy of the secondary or lobar bronchi compared to main bronchi?
Cartilage is not C-shaped, smaller diameter
What is the clinical significance of bronchopulmonary segments (segmental bronchi)?
Can limit spread of infection, and easily be removed
10 on right
8 on left
Each consists of:
- segmental bronchus
- segmental branch of the pulmonary artery
- lung tissue surrounded by a connective tissue septum
Where does gas exchange occur?
Between air in alveoli and blood in the capillaries, O2 diffuses across alveolar wall and enters bloodstream while CO2 diffuses from blood across alveolar wlal to enter the alveoli
What is the innervation and blood supply of the lungs?
Nerves are derived from pulmonary plexuses:
Parasympathetic -> Vagus nerve, stimulate secretion from bronchiol glands, contract bronchiol smooth muscle, and vasodilate the pulmonary vessels
Sympathetic -> Derived from sympathetic trunks, stimulate relaxation of bronchiol smooth muscle, and vasoconstrict pulmonary vessels
Visceral afferent/sensory -> Conduct pain impulses to sensory ganglion of vagus
- *Blood supply** from pulmonary arteries (deoxygenated)
- Once oxygenated, leaves lungs via four pulmonary veins (two for each lung)
- Bronchi, lung roots, and supporting lung tissues receive blood from bronchiol arteries, from the descending aorta
