In what part of the respiratory system are resident flora present?
In the upper respiratory system
What structural feature of the trachea keeps it stable and entact?
C-shaped cartilage rings
Describe Alveoli
Air sacs lined with simple squamous epithelia and surfactant to maintain inflation of alveoli. They are also the site of gas exchange.
What can be an issue with antibiotics in regards of flora?
Antibiotics can destroy resident flora and possibly lead to a yeast infection.
Describe ventilation
Ventilation is the process of acquiring oxygen (inspiration) + eliminating carbon dioxide (expiration) from the blood
What law do the lungs operate under?
Boyle’s law
What does Boyle’s Law determine?
The concept that air will move from high concentration to low concentration
- When we inhale, the movement of the muscles creates negative pressure in the lungs; the pressure inside the lungs is less than the atmosphere, leading air to move in
- When we exhale, the muscles relax, placing pressure on the chest cavity thus increasing the pressure inside the chest cavity; the pressure inside is now greater than the atmosphere, so air expels.
Tidal volume
Amount of air exchanged with normal inhalation and normal exhalation (TV) (Typically 500 mL)
Residual volume
Amount of air remaining after maximum expiration (RV)
Inspiratory Reserve volume
The maximum amount of air inhaled after normal inhalation
Expiratory Reserve volume
The maximum amount of air exhaled after passive/normal exhalation
Vital Capacity
The maximum amount of air exhaled after a maximum inspiration
Total Lung Capacity
The maximum amount of air inhaled
FEV 1
The amount of air forcibly exhaled in 1 second after maximum inspiration
Describe the pathway to hyperventilation
Increased PCO2 in blood and CSF lowers the pH
- This drop in pH stimulates the chemoreceptors
- chemoreceptors trigger the inspiratory muscles
- increases respiratory rate (hyperventilation)
- increased respiratory rate removes more CO2 from the body
Describe the pathway to hypoventilation
Decreased PCO2 in blood and CSF increases pH
- Rise in pH decreases stimulation of chemoreceptors
- decreases action of inspiratory muscles –> decreases respiratory rate (hypoventilation)
- slower respiratory rate retains more CO2
Describe diffusion
oxygen and carbon dioxide are exchanged at the alveolar capillary auctions (ACJ)
- O2 into the cells
- PCO2 escape the body through the lungs
What law determines diffusion?
Dalton’s Law
Gases move based on pressure gradient
Describe diffusion of inspired air with Dalton’s Law
Inspired air has high PO2 and low PCO2, where as the blood in our lungs (to be expelled) body have low PO2 and high PCO2 –> thus the pressure gradient allows O2 to be pulled into the blood and CO2 to be released into the alveoli
What is the typical VQ ration?
0.9 : 1
How much oxygen are dissolved in plasma?
1%
Where are most oxygen?
Bound reversibly to hemoglobin = oxyhemoglobin
What % of CO2 are present in plasma?
7%
What % are reversibly bound to CO2?
20%
