Respiratory 3 Flashcards
What are lung compliance and recoil?
How easily an elastic material can be stretched or inflated
Recoil: the ability of an elastic material to get back into its original position after stretching (inversely related to compliance)
What is Emphysema in regard to compliance and recoiling?
disease with high compliance: (lungs stretch easily based on the pressure of the lung wall (P tp, transpulmonary)
more dead space, less O2 in alveoli?
-> expiration difficult
What is the Compliance-recoil relation in fibrosis?
shows low compliance and high recoil (inspiration difficult)
What is the relation between surface tension and pressure?
greater radius -> less pressure -> lower probability for the alveoli to collapse
smaller radius -> more pressure -> smaller alveoli tend more to collapse
How does the lung prevent alveoli to collapse?
reduction of surface tension through surfactants produced by alveoli cell type 2
reminder: alveoli cell type 1 makes up the wall of the alveoli
How is airway resistance defined?
R aw = delta Pressure / V (of air taken)
contraction of smooth muscle will increase Resistance
dilation will decrease R
Which NS controls air resistance? (When we need more O2)
FIGHT OR FLIGHT: sympathetic
ß2 receptors: dilate bronchioles and relax smooth muscles in walls of airways
How can lung capacity be measured?
Spirometer -> the amount of water you push away
the graph (output): Vol vs time -> Spirogram
What is the tidal volume (TV)? (EXAM)
What is the inspiratory reserve volume (IRV)? (EXAM)
TV: the air we breathe in and out normally with each breathe (500 ml)
IRV: the amount of volume we can breathe in beyond the tidal volume (2100-3200 ml)
What is the expiratory reserve volume (ERV)? (EXAM)
What is the residual volume (RV)?
(ERV): air that can be evacuated after tidal expiration (1000-1200 ml)
RV: air left in the lungs after strenuous expiration (there will always be air left)
What is the inspiratory capacity (IC)?
What is the functional residual capacity (FRC)?
The total amount of air we can inspire after a tidal expiration (IRV + TV)
Amount of air remaining after a tidal expiration (ERV+RV)
What is the vital capacity (VC)?
What is the total lung capacity (TLC)?
VC: the total amount of exchangeable air (TV + IRV + ERV)
TLC: sum of all lung volumes (6000 in males)
Alveolar ventilation
similar to CO = SV * HR
Amount of air we breathe in and out in a minute:
Tidal volume (ml/breathe) * respiration rate (breaths/min) -> ml/min
- MINUS dead space: 150 * respiration rate
Reminder: CO: the amount of blood forced out of the heart by each ventricle per minute
How is the area called where air doesn’t reach the alveoli? (EXAM)
dead space, air that stays in conduction airway, no alveoli (150 ml)
How would you calculate alveoli ventilation? (EXAM)
TV * respiration rate MINUS dead space * respiration rate
How is the lung itself supplied with oxygenated blood?
Through bronchial arteries arising from aorta, doesn´t supply alveoli with blood
Explain the ventilation (airflow) - perfusion (blood flow) inequality!
The upper area of the lung has lower blood flow (due gravity) -> low partial pressure of CO2 (because less CO2-rich blood goes there) ->causing bronchoconstriction -> causing decreased airflow in that area
What happens in areas that have decreased airflow? (due to disease)
Hypoxic pulmonary vasoconstriction
Less blood will be sent to this area, due to vasoconstriction -> because there is less airflow there (pO2 low)
What drives the movement of gases between tissues, blood, and alveoli?
partial pressure, it goes from high pressure to low pressure and it flows until partial pressure in two areas are equalized
What is hyperventilation?
increased alveolar ventilation -> through increased respiratory rate or tidal volume (it’s better to increase volume when you efficiently want to increase your rate=: more O2 to alveoli and more CO2 removed
f.e.: exercise
What is hypoventilation?
reduced alveolar ventialtion -> less O2 in alveoli and less CO2 removed (more CO2)
f.e.: taking oxicodon; respiratory depression
At what point is hemoglboin completley saturated?
at about 100 mm Hg, all 4 heme groups carry O2
(at the pulmonary venous end, when blood receives O2)
At what point is blood considered deoxygenated?
How saturated is blood according to dissociation curve
in the venues of systemic circulation,
with the partial pressure of 40 mmHg, still saturated to 80%
What is the effect of Hemoglobin in terms of partial pressure?
Hemoglobin and bound O2 do not contribute to partial pressure -> Hb will increase the amount of O2 to establish equilibrium again, which was pushed out of balance because of bound O2 to hemoglobin not contributing to partial pressure anymore
Movement of oxygen from the lung to tissue:
O2 moves from alveoli to pulmonary capillary: 2% stays dissolved in plasma, 99% goes into the blood and binds to Hb -> HbO2 (oxyhemoglobin)
in tissue capillary: HbO2 releases O2 -> dissolved O2 moves from tissue capillary plasma to tissue
What affects the release process of O2 from hemoglobin?
(EXAM)
Temperature and pH
Temperature: when we increase temperature, hemoglobin is more act to let go O2 -> makes sense: metabolic active tissues create heat, which facilitates Hb letting go of O2
pH = -log[H+], so as H+ goes up and acidity increases it facilitates Hb letting go O2
makes sense: metabolic active tissues sometimes create acid: f.e lactic acid
Why is Hb affected by pH and temperature?
(EXAM)
Because it is a protein, and pH and temp. affects the function of proteins
