Zones of Respiratory Tract and their function

• conducting- coduits of airflow
• respiratory- gas exchange

trachea

bronchus

bronchioles

• resp. bronchioles
• alveolar ducts
• alveolar sacs (Type I, II pneumocytes)

cilia and smooth muscle

•  
  • walls contain smooth muscle
    • beta 2 receptors
    • cholinergic receptors
  • lining contains cilia and mucus secreting cells

• evaginations of bronchioles or ducts/sacs
• thin walls
• large surface area
• contents
  • type I, II pneumocytes
  • alveolar macrophages

Equation for Inspiratory capacity

Equation for TLC

Define physiological dead space

anatomic

physiologic

Describe hysteresis

• shows the reason why the pressure difference needed to cause inspiration is much more than cause expiration
• this loop is due to surface tension at liquid air interface

• they have lower volume, meaning higher pressure, which makes it more likely to collapse and move to a larger volume connected alveoli
• we must add surfactant to reduce surface tension

• lack of surfactant
• symptoms
  • atelectasis
  • difficulty inflating lungs
  • hypoxemia

• measure ratio of lecthin:sphingomyelin in amniotic fluid
• if greater than two, mature level of surfactant

Concentration = P X solubility

Compare and give the significance of pressure of oxygen and carbond dioxide in pulmonary circulation and alveolus

• pulmonary circulation
  • P oxygen = 40
  • P CO2 = 46
• alveoli
  • P oxygen = 100
  • P CO2 = 40

The pressure differential will drive the movement of oxygen into circulation and CO2 out of the body.

What part of the capillary exchanges alveolar oxygen?

dissolve (2%- about 0.3 mL in blood)

bind to Hb (98%- about 20 mL in blood)

oxygen content = (oxygen binding capacity X        % saturation) + dissolved oxygen

• artery = 100 mm Hg (100% sat)
• vein = 40 mm Hg (75% sat)

• increase carbon dioxide
• increase temperature
• increase 2,3 BPG
• decrease pH

This favors unloading of oxygen, meaning Hb has decreased affinity for oxygen.

• dissolved gas
• bind to Hb
• bicarbonate (90%)

Rxn to produce HCO3

• CO2 and H2O form carbonic acid via acion of carbonic anhydrase
• carbonic acid loses a hydrogen and forms HCO3