Unit 3: Pulmonary Physiology Pt2 Flashcards
What are the 20 generations of branching of the airway in lung?
Trachea –> Bronchi (11) –> Bronchioles (5)–> Respiratory Bronchioles (4) –> Alveolar ducts –> alveolar sacs –> Alveoli
What part of the branching of the airway in the lungs lacks cartilage?
bronchioles and those that follow
What happens to surface area as we go down the branching in the lungs?
surface area increases
trachea has 2 cm^2 and 300 million alveoli have 50-100 M^2
What is the area where gas exchange cannot occur called?
Dead space (mainly the airways)
What are two subcategories of the Dead space of our pulmonary branches?
- Anatomical Dead Space (=150ml)–> airways
2. Physiological Dead Space = anatomical + non-fxnal alveoli
What is the dead space that equals the anatomical dead space plus the non functional alveoli called?
Physiological dead space
How is the dead space calculated?
using a pure O2 inspiration and measuring nitrogen in expired air
– % area x Ve
How do we calculate the Alveolar volume?
= FRC - dead space
= 2300ml - 150ml
= 2150ml
(FRC = functional residual capacity)
Where is most of the FRC (functional residual capacity) at, at the end of a normal expiration?
at the level of the alveoli
How long does it take to turnover the alveolar air?
about 6-7 breaths
What is the equation for the rate of alveolar ventilation?** What does it equal?
Va = RR (Vt - Vd)
Va = alveolar ventilation RR= respiratory rate
Va = ~ 4 L/min**
What are the three ways Efferent Neural control of the airways occurs?
- SNS
- PSNS
- NANC Nerve (non-adrenergic, non-cholinergic)**
What will the SNS efferent neural control have on the airways? What type of receptors?
beta receptors–> causing dilation
What is the direct and indirect way the SNS can effect the airways? Which is predominant?
direct = weak due to sparse innervation
indirect = predominant via catecholamines
What type of receptors does the PSNS use to control the airways? What effect does it have on them?
muscarinic receptors –> causing constriction
What effect do NANC nerves have when they are inhibitory to the airways?
release VIP and NO = bronchodilation
What effect do NANC nerves have when they are stimulatory on the airways?
bronchoconstriciton, mucous secretion, vascular hyperpermeability, cough, vasodilation
= “neurogenic inflammation”
What stimulates the “neurogenic inflammation” of the airways?
NANC nerves (non-adrenergic and non-cholinergic)
What type of afferent nerve receptors are associated with smooth muscle of proximal airways and stretch receptors, involved in reflex control of breathing and cough reflex?
Slow Adapting receptors
What type of afferent never receptors are sensitive to mechanical simulation, protons, low Cl- solutions, histamine, cigarette smoke, ozone, serotonin, PGF?
Rapidly adapting receptors
(some response may be secondary to mechanical distortion produced by bronchoconstriction
What autonomic control of the airways is selectively stimulated by capsaicin?**
C-fibers (high density)
also activated by bradykinin, protons, hyperosmole solutions, and cigarette smoke
What effect will these local factors have on the smooth muscle of the airway?
- Histamine binds to H1 receptors
- Histamine binds to H2 receptors
- constriction
- dilation
(“1 before 2, and C before D”)
What effect will these local factors have on the smooth muscle of the airway?
- Prostaglandins E series
- Prostaglandins F series
- dilation
- constriction
(“take it E-asy and Dilate”
What effect will a slow reactive substance of anaphylaxsis (SRS-A) have on the airway smooth muscle?
constriction–> allergic response to pollen
What will environmental pollution such as smoke, dust, sulfur dioxide, and some acidic elements in smog have on the smooth muscle of the airway? What is this mediated?
elicit contrition of the airways
- parasympathetic reflex
- local constrictor responses
What are the normal levels of HCO3- (bicarbonate)?
= 24 mEq/L
When the HCO3- is less than 24 mEq/L, what is this considered and what will happen to ventilation?
Metabolic acidosis–> stimulate ventilation
When the HCO3- is greater than 24 mEq/L, what is this considered and what will happen to ventilation?
Metabolic alkalosis–> will inhibit ventilation
What regulates the HCO3- (bicarbonate) levels?
the kidney
What is the normal level of CO2 in arterial blood?
40 mmHg*
When we see “metabolic” what should we think? When we see “respiratory” what should we think?
metabolic–> think kidneys
respiratory–> think lungs
What is it considered and what occurs when the CO2 levels in arterial blood is greater than 40 mmHg?
Respiratory acidosis–> will stimulate ventilation
What is it considered and what occurs when CO2 in arterial blood is less than 40 mmHg?
Respiratory alkalosis –> will inhibit ventilation
What regulates the CO2 levels detected in arterial blood?
Lungs
Pulmonary artery wall is _____ as thick as aorta.
1/3 as thick
The Right Ventricle is ____ as thick as the Left Ventricle.
1/3
Do pulmonary arteries have a smaller or larger lumen? Why? ***
larger lumen b/c:
- more compliant
- operate under a lower pressure**
T/F. Pulmonary veins are shorter, but similar compliance compared to systemic veins
True
What is the average total pulmonic blood volume? What percentage is this of total blood volume?
450 ml (9% of total blood volume)
What will shifts in volume from pulmonic to systemic or vise versa have a greater effect on?
pulmonary circulation**
shifts effect the smaller one more
Pulmonic circulation and systemic circulation are in what type of circulation together?
are in series
What are the branches off the thoracic aorta which supply oxygenated blood to the supporting tissue and airways of the lung?
Systemic Bronchial Arteries
What percentage of our CO do the systemic bronchial arteries use?
(they supply blood to supporting tissue and airways of lungs)
1-2%
T/F. The Right ventricle pumps more blood than the left ventricle.
FALSE—- the LV pumps slightly more blood (1%) than the RV
Why does the LV have a slightly higher (1%) output than the RV?
b/c of the drainage into pulmonary veins–> causing it to dump some deoxygenated blood into oxygenated pulmonary venous blood and go to the left atrium, then left ventricle and out of heart
What is the only organ that receives blood flow in excess of cardiac output? Why?
lungs; b/c it receives both total pulmonic flow and some systemic flow simultaneously
What does the Total Flow to the Lungs equal?
= RV output (pulmonic flow) + bronchial artery flow (a small portion of systemic flow from aorta)
T/F. Right ventricular output = 100% cardiac output.
True
What percentage of cardiac output is bronchial artery flow of systemic blood flow?
1-2% of CO
What makes pulmonary lymphatics different than any other lymphatics?**
remove particulate matter absorbed from alveoli**
(also remove plasma filtrate, and escaped protein from vascular system
What is the “respiratory membrane” made up of?
2 layers: alveolar epithelium and capillary endothelium
What helps maintain negative interstitial pressure, which pulls alveolar epithelium against capillary endothelium (aka “respiratory membrane”)?
Pulmonary lymphatics
What are the following mean Pulmonary pressures?
- Pulmonary Artery Pressure =
- Mean Pulmonary Capillary P =
- Major pulmonary veins and left atrium =
- 15 mmHg
- 7 mmHg
- 2 mmHg
If an alveolar has lower O2, what will that cause release of? Why?
local vasoconstrictors –> which automatically redistributes blood to better ventilated areas
(b/c no point to send blood to an area that isn’t getting the oxygen we are trying to take in)
How will the SNS influence the pulmonary vascular smooth muscle?**
cause a mild vasoconstriction
How will the parasympathetic influence the pulmonary vascular smooth muscle?**
cause a mild vasodilation
unique that has parasymathetic innervation at all, usually only have sympathetic influence turning up and down
What is the major constrictor effect on pulmonary vascular smooth muscle?
is low alveolar O2
Under resting conditions, at what point is the blood of the pulmonary capillary fully oxygenated as it is passing the alveoli?
once as passed first 1/3 of pulmonary capillary
even if velocity increase 3x–> fully oxygenation occurs
What is the normal transit time for the oxygenation of blood in the pulmonary capillary? What is it under high CO? Does full oxygenation still occur?
.8 sec
high CO = ~.3 sec; Yes full oxygenation still occurs
When it comes to oxygenation of blood in pulmonary capillaries, what is the limiting fator in exercise?
SV
From the apex to the base of the lungs, will the capillary pressure increase or decrease? why?
capillary pressure increases–> due to gravity
What zone type of the lung will have no flow? Does this normally exist?
Zone 1; does not normally exist
In what is called Zone 1, is the alveolar P greater or less than capillary P?
alveolar P > capillary P
What zone type of the lung will have intermittent flow and it located toward the apex? Describe the P b/w the capillaries and alveolar.
Zone 2
during systole–> capillary P > alveolar P
during diastole: alveolar P > capillary P
What zone type of the lung will have continuous flow and it located toward the base of the lung?
Zone 3 (capillary P > alveolar P)
What zone type will the entire lung be in during exercise?
Zone 3 (= continuous flow; capillary P > alveolar P)
What are the Net forces favoring for the pulmonary capillary dynamics?
filtration by 1 mmHg
Filtration forces = 15 mm Hg from:
- Capillary hydrostatic P = 7mmHg
- Interstitial hydrostatic P = -8mmHg
Reabsorption forces = 14 mmHg from:
- Plasma colloid osmotic P = 28 mmHg
- Interstitial colloid osmotic P = 14 mm
What is the idea gas law?
PV = nRT
P = gas pressure V = vol of gas occupies n = number of moles of a gas R = gas constant T = absolute temp in K (C = - 273)
What gas law is the diffusion of a gas is inversely proportional to the square root of its molecular weight?
Graham’s Law
What gas law is the quality of gas that can dissolve in a fluid is = to the partial pressure of the gas times the solubility coefficient?
Henry’s law
What gas law is the pressure exerted by a mixture of gases is equal to the sum of the ind. (partial) pressure exerted by each gas?
Dalton’s Law of Partial Pressure
What is the term for the pressure that is exerted by the H2O molecules to escape from the liquid to air?
What is this due to?
What is it proportional to?
Vaper P of H2O
molecular motion
temperature
What is the vapor P of H2O at body temperature (37 degress C)?
= 47 mmHg
Atmospheric Air vs Alveolar Air, which is high? H2O vaper Oxygen Nitrogen CO2
H2O vaper = alveolar air
Oxygen = atm air
Nitrogen = atm air
CO2 = alveolar air
What is the most abundant gas in air behind Nitrogen and oxygen?
argon at about 0.93%
How do the follow relate to diffusion across the respiratory membrane?–are they proportional or inversely proportional?
- Temp
- Solubility
- Cross-sectional area
- Sq root of molecular weight
- Conc. gradient
- distance
- temp – is proportional
- solubility – “ “
- cross-sectional area – “ “
- sq root of molecular weight – inversely prop.
- conc. gradient – is proportional
- distance– inversely prop.
(Solubility and MW are properties of gas)
What do relative diffusion coefficients represent?
how readily a gas will diffuse across the respiratory membrane
- are proportional t solubility
- are inversely proportional to sq root of MW
List in order the solubility of the following gases from most to least in a aqueous solution? O2, CO2, N2
CO2 (20.3) > O2 (1.0) > N2 (0.53)
CO2 is ____ times more diffusable than O2.
20x
Nitrogen is ___ as diffusable as O2.
1/2
