Respiratory Flashcards
what are the three components of the blood air barrier
alveoli cell, fused basement membrane, capillary endothelium
what is surfactant and where is it secreted from
secreted from the alveoli cells to reduce surface tension (stops lungs collapsing)
what is the pathway of air down the respiratory tract
nasal and oral cavity, pharynx, larynx, trachea, bronchi, bronchioles, alveoli ducts, alveoli
what is Boyles law
as volume increases, pressure decreases and vice versa
what is Patm
atmospheric pressure, outside the lungs
what is Palv
pressure within the alveoli
what is Pip
intrapleural pressure (within the pleural cavity), negative pressure
inspiration is active or passive
active
pressure in the lungs needs to be __ than pressure in the atmosphere for air to move in
lower
what intercostal muscles are involved in inspiration
external
internal intercostals are used for
forced expiration
what are the inspiration accessory muscles
sternocleidomastoid, pectoralis minor
expiration is active or passive
passive
pressure in the lungs needs to be __ than the atmospheric pressure for air to flow out
higher
the chest tends to __ outwards
recoil
the lungs have elastic elements so tend to __ inwards
recoil
intrapleural pressure is always
negative, like a suction pressure
Vt
tidal volume, volume of air moves in and out during normal quiet ventilation
I
inspiratory
E
expiratory
R
reserve/residual
F
functional
C
capacity
Ve
minute ventilation
Va
alveolar ventilation
Vd
dead space
f
frequency
P
partial pressure
PA
alveolar pressure
Pa
arterial pressure
Pv
venous pressure
IRV
inspiratory reserve volume, extra volume that can be inspired in a forced inspiration
ERV
expiratory reserve volume, extra volume that can be expired in a forced expiration
RV
residual volume, inflation after a forced expiration, to keep lungs from collapsing
VC
vital capacity, maximal breath in to maximal breath out
TLC
total lung capacity, amount of air if you breath all the way in
IC
inspiratory capacity, total amount able to be drawn into lungs after normal expiration
FRC
functional residual capacity, volume in lungs at end of tidal expiration (represents equilibrium as to change volume from here need to do work)
how to calculate VC
ERV + Vt + IRV
how to calculate TLC (total lung capacity)
VC + RV
how to calculate IC
Vt + IRV
how to calculate FRC
RV + ERV
equation for Ve
Vt x f
how many breaths does the average person take per minute
12
how much volume is dead space
150ml
hyperventilation is
fast, deep breathing
hypoventilation is
slow, shallow breathing
equation for Va
f x (Vt-Vd)
the partial pressure of a gas is directly proportional to
its concentration or fractional content
in a mixture of gases, the total pressure exerted is the sum
of the partial pressures
daltons law is to do with
partial pressure
the sum of the partial pressures is called
Patm
how to calculate partial pressure of any gas
fractional content x total pressure
is the PO2 higher in the alveoli or the atmosphere and why
atmosphere as in the alveoli some exchanges out so there is less of it
is PCO2 higher in the alveoli or the atmosphere and why
in the alveoli as some has been diffused from the body into the alveoli
what is Ficks law
F = D x A x (P1 - P2) / T
what is F in Ficks law
rate of diffusion
what is A in ricks law
surface area
what is D in Ficks law
diffusion constant
what does the diffusion constant depend on
gas solubility and its molecular weight
CO2 diffuses __x faster that O2 due to __
20, higher solubility in CO2, even though it has a smaller partial pressure gradient
what is emphysema
decrease in surface area of the lungs leading to decreased PO2 in blood
what is T in Ficks law
thickness
what is pulmonary fibrosis
thickening of alveolar membranes, leading to decreased PO2 in blood
everything above the line in Ficks law is __ proportional to flux
directly, so if they go up, so will flux
everything below the line in Ficks law is __ proportional to flux
indirectly, so if they go up, flux will go down
what is the main factor in flux
partial pressure difference as this drives diffusion of gases from alveolar to arterial
Ficks law of diffusion is related to
flux, diffusion, surface area, partial pressure and thickness
PO2 is __ in muscles than in blood
lower, there is a gradient for O2 to move in
PCO2 is __ in muscles than in the blood
higher, so there is a gradient to move out of the muscles, this increases during exercise
PO2 is __ in the blood than in the alveoli
lower
PCO2 is __ in the blood than in the alveoli
higher
does O2 or CO2 have a larger pressure gradient
O2, however CO2 diffuses 20x faster due to higher solubility
what are the two forms that O2 is transported
combined with haemoglobin and dissolved in plasma
what are the three forms that CO2 is transported
dissolved in the plasma, as bicarbonate, combined with haemoglobin
98% of O2 is transported
bound to haemoglobin
1 Hb molecule can carry __ molecules of O2
4
2% of O2 is transported
dissolved within plasma (around 3mL in each L of blood)
1 Hb molecule has __ haem groups
4
each molecule of O2 that binds to Hb __ another molecule of O2 binding
facilitates
what is the co-operative effect
one O2 molecule binding to Hb making it easier for the next to bind which makes it even easier for the next etc
what is O2 binding to Hb called
oxygenation
is oxygenation reversible
yes, so that O2 can be offloaded to muscles, as one leaves it makes it easier for the next etc
Hb being fully saturated is represented by the percentage
98%, the other 2% is dissolved in plasma
the Hb-O2 saturation of Venous blood is
75%, as one O2 molecule has been offloaded at rest, venous saturation will be lower during exercise as there is more demand for O2 so more is offloaded
the Hb-O2 saturation of arterial blood is
98%, as it has just been oxygenated
the amount of O2 bound to Hb is determined by
the PO2 in the blood
Hb has a high __ for O2 at full saturation, this decreases as O2 is offloaded
affinity
What is the Bohr effect
describes Hb’s affinity for oxygen
what happens in the Bohr effect
a left or right shift in the oxy-haemoglobin dissociation curve which is caused by an increase/decrease in CO2, H+ ions (pH) and temperature
according to the Bohr effect, a left shift occurs in the __ and facilities more ___ of oxygen (increased __) caused by __ levels of CO2, H+ and __ temperature
lungs, loading, loading, lower, low
according to the Bohr effect, a right shift occurs in the __ and facilities more ___ of oxygen (increased __) caused by __ levels of CO2, H+ and __ temperature
tissues, release, unloading, higher, high
how much of CO2 is transported in dissolved plasma
7%
how much of CO2 is transported combined with haemoglobin
23%
how much of CO2 is transported as bicarbonate
70%
when CO2 is bound to Hb (globin chains) Hb has a much __ affinity for O2
lower
is CO2 binding to Hb subunits (globin chains) reversible or irreversible
reversible, so it can be offloaded at gas exchange
conversion from CO2 to HCO3- happens in
red blood cells with enzyme assistance
once CO2 has been converted to HCO3- it can then
move into the plasma and CO2 now travels around the body as HCO3- in the plasma
Remember to learn Spirometry tracing
so you can label the diagram
alveolar ventilation is decreased by
hypoventilation
alveolar ventilation is increased by
hyperventilation
what is PO2 when Hb-O2 saturation is at 75%
40mmHg
what is PO2 when Hb-O2 saturation is at 98%
100mmHg
what is Patm of O2
160mmHg
what is Palv of O2
100mmHg
what is the Fair of O2
0.21
what is Patm of CO2
0.2mmHg
what is Palv
40mmHg
what is the Fair of CO2
0.0004