Respiratory Flashcards
Explain the characteristics of respiratory epithelium and how it differs between the conducting and respiratory airway
Pseudostratified columnar cells with cilia
Conducting epithelium - thick layer of cells to restrict gas exchange. Contains layers of cartilage to keep airway open and mucus producing goblet cells
Respiratory epithelium - single layer of cells
What levels of the airway are conducting and which are respiratory
Conducting - 1-14 (transitional bronchioles at 15)
Respiratory - 16-23
What muscles are used in inspiration
Accessory muscles - elevate ribs and sternum
Principle muscles - external intercostals and diagram
What muscles are used during active expiration
Internal intercostals and abs
What are the characteristics of conducting epithelium that has remodelled
thickening of smooth muscle and basement epithelium.
Thickening of sub mucosal layer that folds inwards into the lumen
Hyperpnea
Increased breathing that matched the metabolic need
Apnea
Absence of airflow due to lack of respiratory effort or airway obstruction (failure to breathe)
Dyspnea
Sensation of laboured breathing (shortness of breath)
What is the effect of neuromuscular control on the work of breathing
It changes the mechanical work of breathing by adapting to the information from the sensors
What areas of the brain are active in breathing - both subconsciously and conscious
Subconscious breathing is regulated in the brain stem - inspiration neurons are always active and expiration neurons become active during active breathing.
As soon as breathing become conscious it is controlled by higher centers in the brain.
What is the only area in the body that can respond to hypoxic blood condition
Carotid Bodies
How does the carotid bodies send information to the brain
Carotid body sensors are located to access the blood heading to the brain. Chemo and baroreceptors are sent to the brainstem via the carotid sinus nerve.
What are responsible for controlling acclimatization
Carotid Bodies
What causes hypocapnia
Hypoventilation
What results from alveolar hypoventilation
Respiratory acidosis
What results from alveolar hyperventialtion
Respiratory alkilosis
What site in the airway is most vulnerable for full obstruction during sleep
Pharynx
How many pharynx obstructions have to occur during sleep for it to be deemed clinical (likely to lead to pathology)
> 5
What occurs during sleep that causes OSAS and how does one overcome it
When neuromuscular control to the head and neck relaxes during sleep, the pharynx can collapse on itself, closing the airway.
Active breathing is required to overcome the obstruction, opening the pharynx.
Explain the difference in SPo2 levels of a patient with OSAS when they are awake and asleep
Awake - flat line
Asleep - oscillatory drops in pressure as airflow is obstructed
What are 3 anatomical and 3 non-anatomical contributors to OSAS
anatomical - narrow airway, crowded airway, collapsible airway
non-anatomical - ineffective pharyngeal dilatory muscle activity in sleep, low arousal threshold to airway narrowing, unstable control of breathing
What are the benefits of oscillometery compared to spirometry
Oscillometry is recorded during normal breathing, thus requires less patient compliance (can be good with children)
Before you begin testing with oscillometry, what recordings must you obtain first
3 artifact recordings with coeffiecnt of variability of <10% in adults and <15% in children
What frequency is used in oscillometry testing
5-50Hz, but typically 5-26Hz. Up to 35Hz can be useful in children.