Physiology- Respiratory part II Flashcards
Why is it beneficial for lungs to vasoconstrict when there is a drop in oxygen
Forces blood to parts of the lungs that are getting better air flow; keeps blood away from dead space
When does vasoconstriction occur in pulmonary circulation
When oxygen levels drop
Ventilation/perfusion ratio
Volume of air perfused in alveoli/BF
Amount of air ventilating an area of lung relative to amount of blood flow that area receives
Ideal ventilation/perfusion ratio
1.0 (perfect matching)
Actual ventilation/perfusion ratio in healthy people
~.8
Why healthy people typically have ratios of ~.8
When standing, gravity causes more blood to flow to bottom of lungs
What happens to VA/Q when there is blockage of air supply to an area of the lung
Decreases
What happens to tidal volume when there is a blockage of air supply to an area of the lungs
Does not decrease, just gets redistributed
Embolus
Anything blocking a blood vessel
What happens to VA/Q when there is decreased BF to an area of the lungs
Increases (because VA stays the same, but Q decreases)
Positive cooperativity
As one oxygen attaches, it makes it easier for others to attach
Positive cooperatively is a property of what blood protein?
Hemoglobin
Why is it important for hemoglobin to have the property of positive cooperativity?
Allows hemoglobin to load oxygen very rapidly and lose it very rapidly
What will happen to the association/dissociation curve of oxygen and hemoglobin in skeletal muscle that is exercising?
It will shift to the right
Why is it valuable for the association/dissociation curve of oxygen and hemoglobin to shift to the right during exercise?
Increases the rapid release of carbon dioxide
Amount of oxygen released from hemoglobin depends on
Amount of oxygen in tissue (PO2)
Three forms of transportation of carbon dioxide
Physically dissolved
Carbamino compounds
Bicarbonate
Feedback loop of respiration
Inspiratory cells are self stimulating–> activate muscles of breathing
Inspirational cells–> gradually stimulate expiratory cells–> inhibit inspiratory cells
Pneumotaxic center–> inhibits inspiratory cells
What can the respiratory center be altered by
Central and peripheral chemoreceptors
What do the chemoreceptors monitor
Oxygen Carbon dioxide pH Carbon dioxide in tissue fluid (PCO2) Oxygen in tissue fluid (PO2)
Where are peripheral chemoreceptors located?
Carotid sinus
Aortic arch
Where are central chemoreceptors located?
Medulla
Peripheral chemoreceptors are more sensitive to
Oxygen
Central chemoreceptors are more sensitive to
Carbon dioxide
What will stimulate an increased rate and depth of breathing
Decreased PO2
Increased PCO2
Decreased pH (increased acidity)
What is lungs role in acid-base control
Alters carbon dioxide levels
Metabolic acidosis
pH below 7.4 due to a metabolic process
What will lungs do in response to metabolic acidosis
Increase rate and depth of breathing
What will kidneys want to do in response to metabolic acidosis
Get rid of hydrogen ions and conserve bicarbonate
Examples of when metabolic acidosis happens
Long term exercise
Diabetes
Metabolic alkalosis
pH above 7.4 due to a metabolic process
What will kidneys want to do in response to metabolic alkalosis
Conserve hydrogen
Lose bicarbonate
What will the lungs do in response to metabolic alkalosis
Not much of an option to conserve carbon dioxide due to need for gas exchange
What can cause metabolic alkalosis
Bulimia or chronic vomiting
Antacid abuse
Respiratory alkalosis
pH above 7.4 due to respiratory system
What will kidneys want to do in response to respiratory alkalosis
Kidneys will not have much of an effect because this is typically an acute situation and the kidneys have slow action
What will the lungs want to do in response to respiratory alkalosis
Conserve carbon dioxide
What is an example of respiratory alkalosis
Hyperventilation (decreased carbon dioxide, increased constriction….you will pass out)
Respiratory acidosis
pH below 7.4 due to respiratory system
What will the kidney want to do in response to respiratory acidosis
Lose hydrogen ions
Conserve bicarbonate
What will lungs want to do in response to respiratory acidosis
Lose carbon dioxide
…but has difficulty with this due to poor gas exchange, so the body relies mostly on kidney; lungs malfunction
What can cause respiratory acidosis
Emphysema Hypoventilation (drug overdose, head trauma, heat stroke)
