Exam 5 4.20 Pulmonary.Part 1 Flashcards Preview

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2 structures in the upper airways (conducting airways) 

  • Nasopharynx

  • Oropharynx


2 things to know about the Larynx

  • Connects upper and lower airways

  • site of vocal cords


3 structures of the Lower airways- and general description of each

  1. Trachea – branches into 2 main airways at the carina, R and L bronchi

  2. Bronchi – enter lung at the hilum of each lung

  3. Terminal bronchioles – tree-like division of bronchi into bronchioles, until the smallest ones connect to the alveoli


3 structures of the Gas-exchange airways

  • Respiratory bronchioles
  • Alveolar ducts
  • Alveoli 


Two types of Epithelial cells in Alveoli

  • †Type I alveolar cells - Alveolar structure
  • †Type II alveolar cells - Surfactant production


True or False: ˜Pulmonary circulation has a higher pressure than the systemic circulation


It has a lower pressure


One-third of pulmonary vessels are filled with what? 

Filled with blood at any given time

  • This allows space for extra blood during ↑ cardiac activity, keeping pulmonary pressure stable



Where does Pulmonary artery enter the lungs?

Pulmonary artery divides and enters the lung at the hilum



What does each bronchus and bronchiole have?

˜an accompanying artery or arteriole


˜3 things to know about alveolocapillary membrane

  • Formed by the shared alveolar and capillary walls

  • Gas exchange occurs across this membrane

  • Any disorder that thickens this membrane impairs gas exchange


3 basic points about ˜Pulmonary veins and circulation

  • Each drains several pulmonary capillaries
  • Dispersed randomly throughout the lung
  • Leave the lung at the hila and enter the left atrium


What makes up the chest wall? 

  • Skin, ribs, and intercostal muscles
    • Function is protection and muscular support for breathing
  • Thoracic cavity
    • Encases the lungs


What makes up the pleura? 

  • Is a serous membrane
  • Parietal and visceral layers
  • Pleural space (cavity)
  • Pleural fluid


How much Pleural fluid do we have and why do we have it? 

about 1 ½ teaspoons around each lung, just enough to provide surface tension between parietal and visceral layers


Define ˜Ventilation

Mechanical movement of gas or air into and out of the lungs


What is Minute volume and some norms?

  • Ventilatory rate multiplied by the volume of air per breath (tidal volume)
  • Average breaths per minute is ~ 14-18
  • Average tidal volume is 8-10 ml/kg of weight (book uses 500 ml as an average)

Example: For a 70 kg (154 lb.) person, 15 breaths/minute
70 X 10 X 15 = 10,500 ml = 10.5 L



Major muscles of inspiration

  • Diaphragm
  • External intercostals – “hands in front pockets”



Accessory muscles of inspiration

  • Sternocleidomastoid muscle
  • Scalene muscles



Accessory muscles of expiration

•Abdominal intercostal muscles

•Internal intercostal muscles – “hands in back pockets”

•There are no major muscles of expiration –it’s a passive event


What is the Function of surfactant in ˜Alveolar surface tension and ventilation? 

How does it work? 

When things go wrong....

  • reduces surface tension 
  • liquid molecules exposed to air tend to adhere to each other
  • Lack of surfactant is a major reason that premature babies require ventilator support



Why are there elastic properties of the lung and chest wall?

  • ˜maintains normal negative pressure of pleural space
  • Elastic recoil – lungs will return to resting state after inspiration, thereby permitting passive expiration
  • Compliance – relative ease of lung “stretching”
  • Volume change per unit of pressure change
    • Determined by alveolar surface tension and elastic recoil


Changes with elasticity in lung that occur with aging and pathology 

  • ↑ with normal aging and disorders such as emphysema; stretch too easily
  • ↓ in ARDS (acute respiratory distress syndrome, pneumonia, fibrosis, pulmonary edema); stiffer



What determines ˜Airway resistance?

Determined by size of airway and density, viscosity, velocity of the gas


Some causes of increased airway resistance

  • Bronchoconstriction
  • mucus
  • inflammation 



Muscular effort ↑ in the work of breathing with these 3 issues 

  1. Lung compliance ↓ (fibrosis, pulmonary edema)
  2. Chest wall compliance ↓ (obesity, spinal deformity)
  3. Airways are obstructed by spasm or mucous (asthma, acute bronchitis)


What is measured when taking Measurement of Gas Pressure?

  • Pressure and volume measurements made in pulmonary function testing labs specify the temperature and humidity of gases at the time of measurement
  • Air is 78% N, 21% O2, rest is water vapor, CO2, minute concentrations of noble gases


Points about ventilation and perfusion (6)

  • ˜Distribution of ventilation and perfusion – need to have an approximately even distribution of gas (ventilation) and blood (perfusion) in all parts of the lung

  • Gravity and alveolar pressure – the most dependent part of the lung will have the best perfusion (fig. 25-14, p. 671)

  • If gas pressure in alveoli exceeds the blood pressure in the capillary, the capillary collapses and flow ceases

  • Ventilation-perfusion ratio (V/Q ratio)- Perfusion exceeds ventilation in the bases, and ventilation exceeds perfusion in the apices

  • Normal V/Q is 0.8, with perfusion exceeding ventilation

  • Body position changes the areas of perfusion and ventilation 


Location of O2 transport and determinants of arterial oxygenation 

  • Diffusion across the alveolocapillary membrane – takes ~0.75 second
  • Determinants of arterial oxygenation:
    • Hemoglobin binding – O2 moves to the RBCs and binds with hemoglobin
    • Oxygen saturation (Sao2) is % of available hemoglobin bound to O2; measured with oximeter
    • Important measure of pulmonary function


Pic of the various volumes and whatnot in lung capacity


What is spirometry? 

˜how much air inhaled, and exhaled, and how quickly