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2nd semester midterm Physiology Exam

1280 viewsPhysiology
1

regarding cough reflex :

  • Is produced mainly by stimulation of mechanoreceptors in the bronchial wall
  • afferent Nerve fibers pass via vagus nerve 
  • cough begins with forced expiration followed by deep inspiration wih closed glottis
  • cough begins with forced expiration followed by deep inspiration with opened glottis

central chemoreceptors respond mainly to :

  • Hypoxemia
  • respiratory alkalosis
  • hyperventilation
  • hypercapnea

intra pleural pressure :

  • Is equal to -3 mm Hg at end of normal inspiration
  • Is equal to -6 mm Hg at end of normal expiration
  • becomes positive in valsalva s experiment 
  • becomes positive in muller s experiment

intra-alveolar pressure :

  • Is negative during normal expiration
  • Is negative during deep inspiration with closed glottis
  • Is positive during normal inspiration
  • a and b are correct

surfactant :

  • Is secreted by type II alveolar endothelial cells
  • increases work of breathing
  • increass the compliance of the lung 
  • prevents inflation of the lungs after birth

Airway resistance :

  • is increased by sympathetic stimulation
  • is controlled by the radius of airway
  • does not affect work of breathing
  • None of the above is correct

regarding dead space :

  • anatomical dead space is slightly more than physiological dead space
  • physiological dead space is increased during respiratory diseases that affect the function of alveoli
  • dead space causes less O2 tension in the expired air compared to the alveolar air
  • None of the above

oxygenation of venous blood at the lungs increases O2 tension of the blood (PO2). this increase in PO2 :

  • Affects the CO2 dissociation curve
  • decreases the saturation of haemoglobin
  • stimulates respiratory center and leades to hyperventilation
  • None of the above

Bohr effect is the effect of :

  • CO2 on the affinity of haemoglobin to O2 
  • O2 on the affinity of haemoglobin to CO2
  • 2,3 DPG on the affinity of haemoglobin to O2
  • increased saturation of haemoglobin to O2

which of the following conditions increases the delivery of oxygen to tissues :

  • decreased temprature 
  • increased H+ concentration
  • decreased PO2
  • All of the above