Respiratory Physiology Flashcards
What is the equation for physiologic dead space?
Vd=Vt x (PaCO2 - PeCO2) / (PACO2)
PACO2 is PCO2 of alveolar gas
PECO2 is the PCO2 of expired air
What is the equation for minute ventilation
Minute ventilation= Tidal Volume x breaths/minute
In an obstructive lung disease, what happens to the FEV1/FVC ratio?
Decreases
In a restrictive lung disease, what happens to the FEV1/FVC ratio?
Increases
Describe the changes in lung compliance that occurs in emphysema?
The lung compliance is increased and the elastic recoil is decreased making the tendency for the lungs to collapse is decreased. This makes the tendency of the lungs to expand less than the tendency to collapse so the body tries to create a new functional residual capacity so that these forces are balanced.
This will INCREASE the volume of the chest making the barrel shaped chest
Describe the lung compliance changes that occur with fibrosis?
The lung compliance is decreased and the elastic recoil is decreased. Tendency of the lungs to collapse is increased, resulting in a compensatory lower FRC to balance the forces
Large alveoli have (low/high) collapsing pressures and are _____ to keep open
Low and easy to keep open
Small alveoli have (low/high) collapsing pressures and are ______ to keep open
High and are difficult to keep open
Describe asthma in terms of FEV1/FVC and FRC
Asthma is an obstructive disease
FEV1/FVC is decreased
Air trapping from the asthma is increased
Describe COPD in terms of FEV1/FVC and FRC
COPD is an obstructive disease
FEV1/FVC is decreased and the FRC is increased that can lead to a barrel chest
Blue bloaters
What are some things that cause the hemoglobin O2 curve to shift to the right
The affinity of Hb to O2 is decreased
- Increases in PCO2 or decreases in pH
- Increases in temperature from exercise or something
- Increases in 2-3 DPG concentration
What are some things that cause the hemoglobin O2 curve to shift to the left?
The affinity of Hb to O2 is increased
- Decreases in PCO2 or increases in pH
- Decreases in temperature
- Decreases in 2-3 DPG
- HbF
- CO poisoning
Describe the 3 zones that are present in the lungs
Zone 1 is at the apex of the lung
Zone 2 in the middle
Zone 3 is at the base of the lung
Where is the blood flow the most in regard to the 3 zones of the lung?
Zone 3 or the base bc gravity
Airflow is highest at the base as well because gravity
At the apex (Zone 1) of the lung, the V/Q ratio is (higher./lower), PO2 is the (highest/lowest) and PCO2 is the (highest/lowest) because gas exchange is (more/less) efficient.
At the apex (Zone 1) of the lung, the V/Q ratio is HIGHER, PO2 is the HIGHEST) and PCO2 is the LOWEST because gas exchange is MORE efficient.
At the base (Zone 3) of the lung, the V/Q ratio is (higher./lower), PO2 is the (highest/lowest) and PCO2 is the (highest/lowest) because gas exchange is (more/less) efficient.
At the base (Zone 3) of the lung, the V/Q ratio is LOWER, PO2 is the LOWEST and PCO2 is the HIGHESTbecause gas exchange is LESS efficient.
A man comes in with steak lodged in his throat. What is going to happen to his V/Q, PO2 and PCO2, and the A-a gradient?
V/Q will be zero and the PCO2 and PO2 will reach their venous levels in time because there is no perfusion. The A0-a gradient is increased
The dorsal respiratory group is responsible for (inspiration/expiration)
The ventral respiratory group is responsible for (inspiration/expiration)
DORSAL: INSPIRATION
VENTRAL: EXPIRATION
DIVE
What are the input and output for inspiration from the dorsal respiratory group?
Input: vagus and glossopharyngeal nerves
Output: Phrenic nerve
Describe the effects of pregnancy on the respiratory system
Pregnancy can cause chronic hyperventilation from the progesterone
This can lead to respiratory alkalosis with metabolic compensation (increased renal bicarb excretion)
