Module 7 - Pulmonary / Respiratory Flashcards
Exam 3
Respiratory zone
Where gas exchange occurs
Conducting zone
Area that is transferring the O2 into the respiratory zone
Name 3 functions of the nostrils / nasal passage
(1) warm / humidify / moisten the air
(2) get air into the body
(3) filtration of particles
What do the nasal passages, trachea, and bronchi have in common?
They both have ciliated mucous membranes / epithelial cells that filter out pathogens and debris.
the two membranes in the lungs are called?
visceral and parietal membranes
Which membrane is interior and which is exterior in the lungs?
Visceral = interior
Parietal = exterior
The space between the visceral and parietal membranes
Pleura
What is inside the pleura?
Thin space with a small amount of fluid
What is the purpose of the pleura?
Prevent friction during the breathing process
Type I alveolar cells are made up of what type of cells?
Simple squamous epithelial cells
What is the function of Type I alveolar cells
Responsible for gas exchange
What is the function of Type II alveolar cells?
Produce surfactant
What is surfactant?
Lipoprotein that reduces surface tension and prevents the alveoli from collapsing
Why is surfactant important?
Surfactant reduces surface tension, which allows the alveoli to inflate, ultimately allowing for gas exchange to occur
Gas Exchange definition
Getting oxygen into the body and getting CO2 out of the body
What are the 4 phases of gas exchange?
Ventilation
External Respiration
Gas Transport
Internal Respiration
Process by which we get air from the atmosphere into the lungs and vice versa
Ventilation
Process by which we get gas from the type I alveolar cells into the blood, and other gasses from the blood into the type I alveolar cells
External respiration
Transport of oxygen to metabolically active tissues and transport of CO2 from the tissues back into the lungs
Gas transport
Gas exchange from blood with metabolically active tissue; O2 in and CO2 out
Internal respiration
Boyle’s Law
At a constant temperature for a fixed mass, the absolute pressure and the volume of gas are inversely proportional.
Dalton’s Law
In a mixture of non-reacting gasses, the total pressure exerted is equal to the sum of the partial pressures of the individual gasses.
Henry’s Law
The amount of gas dissolved in a liquid is directly proportional to the partial pressure of that gas
Law of Laplace
Pressure required to keep the alveoli from collapsing (P) is proportional to tension (T) and inversely related to the radius of the alveoli (P = 2T/r)
During inspiration, what is Palv and Patm?
Palv < Patm
During expiration, what is Palv and Patm?
Palv > Patm
Palv stands for?
alveolar pressure
intrapulmonary pressure
intra-alveolar pressure
(synonymous)
Pip stands for?
Intrapleural pressure
What is intrapleural pressure?
The pressure inside the pleura; hydrostatic pressure because the pleura has the small amount of liquid
What is alveolar pressure?
The pressure inside the lungs / alveoli where gas exchange occurs
What does TP stand for?
Transpulmonary pressure
What is transpulmonary pressure (TP)?
Difference between alveolar pressure and intrapleural pressure
The pressure difference holding the lungs open
During inspiration, are we changing Palv or Patm?
Palv
What helps to generate subatmospheric pressure of the Palv?
Diaphragm and inspiratory intercostals contract d/t phrenic nerve innervation
Diaphragm pulls down on parietal pleura and the ribcage opens
Thorax area then opens
T/F: There will always be some elastic recoil force during inspiration.
True
If we pull down on the parietal pleura and we have some elastic recoil, what happens to the volume of the pleural region?
Pleural region volume will increase, Pip will decrease
At the end of inspiration, which pressure changes?
Transpulmonary pressure (TP) increases
What does the increase in TP cause?
Lungs to expand
What values are we ultimately trying to reduce (pressure) to get air into the lungs?
Palv
What governs Palv?
(1) Mechanics of increasing thoracic volume
(2) PiP will decrease
(3) TP will increase
What happens if the lungs expand?
Palv will decrease and become subatmospheric
What happens when the diaphragm relaxes?
Phrenic nerve relaxes, parietal pleura no longer being stretched, elastic recoil still present and this pushes the volume to decrease and pressure to increase
The amount of air inhaled or exhaled in one breath
Tidal Volume (TV)
The amount of air in excess of tidal inspiration that can be inhaled with maximum effort
Inspiratory Reserve Volume (IRV)
Maximum amount of air that can be inhaled after a normal tidal expiration (TV + IRV)
Inspiratory Capacity (IC)
Amount of air in excess of tidal expiration that can be exhaled with maximum effort
Expiratory Reserve Volume (ERV)
Amount of air that can be exhaled with maximum effort after maximum inspiration
Vital Capacity (VC)
Amount of air remaining in the lungs after maximum expiration
Residual Volume (RV)
Ohm’s Law
Flow = Pressure gradient / Resistance
What is the most important factor of resistance?
Radius of the airways
In Ohm’s Law, what is the pressure gradient in reference to?
Palv and Patm
What are the two major determinants of lung compliance?
(1) stretchability of the lung tissues
(2) surface tension at the air-water interfaces within the alveoli
Which law explains why partial pressure of O2 in the alveoli (PAO2) is 105 mmHg?
Henry’s Law
PAO2 stands for?
Partial pressure of O2 in the alveoli
PaO2 stands for?
Partial pressure of O2 in the arteries
What regulates diffusion?
Fick’s Law
What are the factors that increase Flux?
Pressure gradient, surface area, diffusion, permeability
What factors oppose flux?
Thickness
Distance
Why is the V/Q Ratio important?
In order for O2 to get into the blood and RBCs, we need a supply of blood to the area of the lung that is receiving the O2
The normal V/Q ratio is what?
0.8
What does it mean if V/Q ratio >0.8?
Ventilation is high, Perfusion is low; ventilation is exceeding perfusion in that area
What does it mean if V/Q ratio <0.8?
Perfusion is high, Ventilation is low; Perfusion is exceeding ventilation in that area
Name 2 causes of V/Q ratio < 0.8.
Asthma, airway obstruction
Name 2 causes of V/Q > 0.8.
pulmonary hypertension, pulmonary embolism (less blood to the area)
Would someone with COPD have a high or low V/Q ratio?
Low because low ventilation, higher perfusion
Why does hypoxic vasoconstriction occur in people with COPD?
Body will try to restore the V/Q ratio naturally by constricting the vasculature that normally supplies blood to that area of the lung that is not working –> decrease perfusion to match to ventilation
Why do people with COPD sometimes get pulmonary hypertension?
Decreased SA, we don’t want to waste blood in that area, so we constrict blood vessels in that area –> increases pressure in the vasculature –> leads to hypertension
CaO2 stands for?
Total arterial oxygen content
What is the most important factor of CaO2?
Hemoglobin
SaO2 stands for
Hemoglobin O2 saturation expressed as a fraction
What are the three key factors of CaO2?
Hb, SaO2, and PaO2
What are the two constants in the CaO2 equation?
0.003 - solubility for O2
1.39 - oxygen binding capacity of Hb
What is a normal Hb?
11-16
What is a normal SaO2?
93-98%
What is a normal PaO2
80-100 mmHg
What variable can we alter by the use of hyperbaric therapy?
PaO2
During anemia, there is a ____ in RBC, which causes ____ to Hb and O2 delivery
decrease, decrease
What factor does anemia affect in terms of the CaO2 equation?
Hb
What factor does Pulmonary Disorders / COPD affect in the CaO2 equation?
SaO2 and PaO2
Why does pulmonary disorder / COPD result in a similar CaO2 as normal?
Because Hb is not affected and because of compensation
What state is iron in in Hemoglobin?
Ferrous state
What is the structure of Hb?
4 globin units; 2 alpha, 2 beta
The deoxygenated Hb form is also called?
T / Taut configuration
During which configuration (taut or relaxed) does O2 bind better?
Relaxed configuration
Cooperative binding
once one O2 binds to a globin unit, it makes it easier for the 2nd, 3rd, and 4th to bind
PaO2 is influenced by what 4 main factors?
(1) Composition of inspired air
(2) Alveolar ventilation
(3) Oxygen diffusion between alveoli and blood
(4) Adequate perfusion of alveoli
Why is O2 therapy used to increase PaO2?
Because O2 therapy will alter the composition of inspired air to increase the amount of O2 available to get into the body.
What 3 factors affect alveolar ventilation?
(1) rate and depth of breathing
(2) airway resistance
(3) lung compliance
If you have narrowing of the airways, this will _____ resistance and ______ PaO2
increase, decrease
Alveolar ventilation is related to what factor in Fick’s Law?
Pressure gradient
What two factors impact oxygen diffusion between alveoli and blood?
(1) surface area
(2) diffusion distance
T/F: As membrane thickness increases, membrane diffusion increases.
False.
If you have a high V/Q ratio, how will this affect diffusion?
Diffusion will decrease or stop altogether because there is no blood perfusing to the area for the O2 to enter into
When we have a high PaO2, the SaO2 will do what?
Increase
When PaO2 drops below 80 mmHg, what happens to SaO2?
This is when we start to see SaO2 drop / decrease.
What makes it difficult for O2 to bind to Hemoglobin in the Taut configuration?
O2 is not on the same plane so it has trouble binding
What disrupts the electrostatic interactions between globin molecules?
When O2 binds
When electrostatic interactions are disrupted between globin molecules, what happens next?
It allows for the iron to get on the same plane as the porphyrin –> makes it easier for other O2 to bind to the iron
Triggers Relaxed state
