3. Respiratory Physiology I Flashcards
Pulmonary anatomy
Conducting passages – getting the air to where exchange occurs
– Nasal cavity: filters, warms, moistens ____
– Pharynx:oral and nasal cavity meet, ____
– Larynx: ____
– Epiglottis: flap over ____ when swallow
Covered in mucus, ____ to keep damaging agents away
Some structures enclosed in ____ to ensure open during negative pressure. Muscle keeps open smaller tubes.
air mouth breathing voice box trachea cilia cartilage
Pulmonary anatomy
Respiratory structures: where gas exchange occurs
Respiratory Structures:
•Bronchioles: ____
•Alveolar sacs: clusters of alveoli
•Alveoli – increase ____ for exchange (200 micrometers in diameter)
Respiratory Structures:
Maximized for ____
Closely accompanied by ____
____ in bronchioles to control diameter
* This is where gas exchnage occurs! * 1/5 of a cm is an alveoli * Surrounded by capillaries - optimized exchange between air and blood
terminal tubes
surface area
gas exchange
vasculature
smooth muscle
Intrapleural space
The lung floats in the pleural cavity –the lungs are not attached but ____ in the thoracic cavity. ____ lubricates the movement of the lungs in the cavity. The pleural cavity is continuously drained by ____, which cause the pleural cavity to be maintained at a ____.
____: infection of the pleural cavity. Very ____. Often sign of additional ____
* The lungs are not attached to the pleural cavity - they float * Intrapleural space is filled with fluid which is critical for the physics of the exchange of gases, fluids and air * Slightly negative pressure
“float”
pleural fluid
lymphatics
negative pressure
pleurisy
painful
pathology
Pulmonary ventilation
- Normal breathing
• Inspiration – \_\_\_\_ of diaphragm pulls lungs down – \_\_\_\_ forces air into the increased space of the lungs (\_\_\_\_ Law) • Expiration – \_\_\_\_ – \_\_\_\_ of lungs, chest wall – Air leaves
• In normal passive breathing > contraction of diaphragm > space inside the cavity pulls the lungs down ○ Via boyle's law > inc in volume, pulls air into the lungs • Expiration in passive state > relax muscle, springs back to normal space > decreasing volume in cavity > elastic recoil leads to pushing of the air
contraction atmospheric pressure boyle's passive elastic recoil
Boyle’s Law
• Pressure inversely proportional to ____ at constant mass,
temperature
– as volume expands, pressure ____
– As volume shrinks, pressure rises
• Explains why air enters lungs, because air rushes in to
equalize ____. If inhale with passages closed, ____.
• Decrease the volume, pressure will increase
volume
decreases
pressure
vacuum
Boyle’s Law in every breath
• Pressure inversely
proportional to ____ at
constant mass, temperature
• Pressure is proportional to 1/V
volume
Pulmonary Ventilation – extra muscular help for heavy breathing in exercise
• Additional ____ increase rate and magnitude of air influx. The thoracic rib cage moves upward and outward, increasing the volume of the thoracic cavity
- Muscles of Inspiration
- external intercostals: raise ____
- sternocleidomastoid – up on ____
- scalleni – lifts ____
- anterior seratus – lifts other ____
- Muscles of Expiration
- ____
- ____
- More than just the diaphgram contracting and relaxing
- Breathing out can be most problematic in certain diseases
muscles
rib cage
sternum
1st 2 ribs
ribs
abdominal recti
internal intercostals
Pulmonary pressures: inspiration and expiration
- ____ changes as breathe in and out
- ____ changes as breathe in an out – try inhaling when close epiglottis
- Pleural pressure: pressure of pleural fluid between ____. Constant drainage gives ____, holds lungs in place. Lowest at ____
- Alveolar pressure: pressure of air in alveoli. ____ at rest. ____ during inspiration, ____ during exhalation
- Transpulmonary pressure: ____. Elastic forces, r____
- Changes in all variables most rapid during ____ phases• Breath in:
○ Volume in lungs increases, and then you exhale and it decreases
• Pressure
○ Alveolar pressure
§ Pressure starts at ____ because it’s In balance with the outside air (want it to be in equilibrium)
§ Start to breathe in > negative pressure, because the pleural pressure is very negative > increasing the volume creates a vacuum in pleural cavity and tugs on alveolar and opens them up a bit
§ Reach top of inspiration; pleural is at it’s lowest point, but the alveolar pressure ____; when you exhale > ____ > translated into increased pressure in alveolar spaces that slowly goes down
○ Transpulmonary pressure
§ Changes in pressure are greatest at the ____, and slow down when you get to the end of inspiration/expiration
• Why does alveolar pressure rise at end of inspiration?
○ Start at vacuum > and now you have more air in your lungs and now pressure is ____ (alveoli is given enough time to equilibrate the pressure)
• As air leaves you get equilibration in ____ and alveolar pressure
volume pressure lung and cavity negative pressure max lung volume atmospheric negative positive
pleural pressure - alveolar
recoil pressure
early
0
increasing
contraction
beginning
increasing
atmospheric
Pulmonary pressures: Differences in pressures drive airflow
Why do alveolar pressures change? ____
• Atmo pressure before inspiration is same as \_\_\_\_ pressure; and pleural is \_\_\_\_ • As inpsire > increase vacuum > pleural goes down to \_\_\_\_, creates a vacuum instead the alveoli > air rushes in > equlibrates at \_\_\_\_ • Opposite at expiration ○ Contraction > net increase in pressure in \_\_\_\_ pressure > increase pressure of \_\_\_\_ space > pushes air out ○ Equilibration of air here and air outside • Why do alveolar pressures change > air coming in and \_\_\_\_, and the \_\_\_\_ and \_\_\_\_
boyle’s law
alveolar pressure
-4
-6
0
pleural
alveolar
equilibrating
muscles
Boyle’s law
Compliance
How much does the volume change for a given increase in ____; balloon vs. soccer ball
Caused by
- ____ of lung itself: collagen and elastin.
- ____
Need ____ more pressure to increase volume for lung filled with air than fluid. This difference due to ____ forces.
Surface tension is ____ of lung elasticity
• Compliant - amount of forces you need to expand lung and [???] • Increase the pressure, and the volume of the lung expands quickly ○ Do not need a big increase in pressure to inflate it • [???] ○ Why does it need more pressure to expand on air than just water • [???]
pressure
elastic forces
surface tension
3x
surface tension
2/3
Surface tension
Molecules at edge form ____ bonds, water drop attempts to ____ at surface.
LaPlace’s law
Pressure = 2 x surface tension
radius of alveolus (100 μm)
Need more pressure to inflate alveolus if ____ high, or ____ small, to stop collapse
• Water molecules bonding are happier when it contact with other \_\_\_\_ and not the air • Sphere shape - bondings try to contract the shape and keep this in a \_\_\_\_ more stable situation • If alveoli is small > takes more pressure to take it to cause to open up, or it will \_\_\_\_ upon itself ○ A \_\_\_\_ alveolus is likely to collapse upon itself ○ The way the body deals > uses \_\_\_\_ along the \_\_\_\_, that disrupts the surface tension; the forces that try to pull the alveoli onto the itself
stronger
contract
surface tension
radius
water molecules thermodynamically collapse larger surfactant edge
Surface tension in lung
- In lung, surface tension from fluid coating acts to ____ alveoli
- Pulmonary surfactant – ____
- Detergent-like phospholipid breaks up ____ bonding, surface tension.
- Secreted by ____ cells, released in ____.
- Produced in ____ trimester, so ____ infants given surfactant
- Used to be why premature babies died
- DPPC is secreted by type II alveolar > breaks up the bonding of water molecules and weakens the ____ it tries to get it to collapse upon itself
- Key steps in neonatal survival > added surfactant to neonatal babies > their lungs would not collapse
collapse DPPC (dipalmitoylphos phatidylcholine) H2O type II lamellar bodies 3rd premature force
____ used to measure pulmonary volumes
• Used to get a basic measure of amount air you can ____ into your lungs
spirometer
fit
Pulmonary volumes
Tidal volume: VT -____ breath – ____ L
Inspiratory reserve volume: IRV – ____ with full force - ____ L
Expiratory reserve volume: ERV- ____ with full force. ____ L
Residual volume: RV ____ L
Note: Volumes here are for average young male. Females 25% less. Also ____ for smokers.
• Tidal volume ○ Sitting calmly, diaphragm is contracting and relaxing • Inspiratory reserve volume ○ \_\_\_\_ chest wall as much as you can; getting as much air in as possible ○ 3 L - can put a lot more air in your lungs when you do it \_\_\_\_ • Expiratory reserve volume ○ Exhale as much volume as possible • Residual volume ○ The little bit of air that's always \_\_\_\_ over
normal
0.5
inspire
3
expire
1.1
1.2
reduced
expand
actively
left
Pulmonary capacities
Inspirational capacity: IC
IC=____
IC = ____ L
IC = max ____
Functional Residual Capacity: FRC
FRC=____
FRC=____ L
FRC=air in lungs after ____
Vital Capacity: VC VC=\_\_\_\_ VC = \_\_\_\_ VC=\_\_\_\_ L \_\_\_\_ then \_\_\_\_
Total Lung Capacity: TLC TLC=____
TLC=____
* Everything you can inspire is from bottom of tidal to the top of IRV * Vital capacity - the total range of air you can fit into your lungs
VT+IRV
3.5
inspiration
ERV+RV
2.3
normal expiration
IRV + VT + ERV IC + ERV 4.6 inhale maxillary exhale maxillary
VC+RV
IC+FRC
Summary - Pulmonary Ventilation
- Gas exchange occurs in ____, not conducting passages
- Contraction of diaphragm enough for ____, additional muscles needed for ____
- Increased pulmonary volume creates ____, pulls air into alveoli
- Surface tension decreases ____, lessened by ____
- Pulmonary volumes, capacities quantify air regions• Surface tension makes it more difficult to open up the small alveoli
respiratory structures
normal breathing
heavy breathing
negative pressure
compliance
surfactant
Pulmonary circulation
Getting O2 to the blood and removing CO2
Blood passes through pulmonary capillaries in ____ sec normally, ____ sec with increased cardiac output
Note: pulmonary arteries blue because lacking in O2, pulmonary veins red because oxygenated.
Pulmonary arteries wider____, thinner ____ than systemic; more compliant to accommodate stroke volume of ____, dissipate pressure
0.8
0.3
bore
walled
right ventricle
Pulmonary blood pressures
• Pulmonary artery pressure like ____ for systole, ____ during diastole. Both less than ____
• Pulmonary pressures (mmHg) S=25, D=8, Mean = 15. Fall
rapidly to ____ mm Hg in pulmonary capillaries (peripheral capillaries ____ mm Hg). Helps ____
• RVC goes up and down during contraction ○ Ventricular pressure goes down because the muscle is relaxing • PAC goes down, but not to same extent ○ Some pressure is \_\_\_\_ • Changes in pressure that occurs in PA with \_\_\_\_ ○ Very rapidly, once to the capillaries you have a steady pressure of \_\_\_\_mmHg § Important for dynamics of exchange of air and fluids § Want changes in pressure eliminated by the time you get to the \_\_\_\_
right ventricle
higher
aortic pressure
7
17
gas exchange
kept
distance
7
pulmonary capillaries
Hypoxic pulmonary vasoconstriction
Matching blood and air flow
• Key point to get blood to alveoli with most ____
• Normally, pulmonary vessels adjust to increasing PO2 by ____ and to decreasing PO2 by ____.
• Stretching of alveoli releases ____, dilates pulmonary arteries
• If oxygen in alveoli fall below 70% of normal, less ____, adjacent blood vessels ____, increase vascular resistance: hypoxic lung ____.
• Opposite in systemic vessels where low oxygen ____ vessels to increases
flow. ____ in body, ____ in lung.
* Make sure you're getting blood to alveoli with most oxygen; don’t waste blood in areas that don't have a lot of oxygen * Reduction in stretching > reduction in release of NO > reduction in dilation, resulting in less blood being diverted to the alveoli > increases vascular resistance * Deposit in body, withdraw in the lungs
oxygen enlarging contracting NO NO constrict vasoconstriction
dilates
deposit
withdrawal
Dead Space: air that does not reach respiratory structures, no gas exchange
Anatomical dead space: Anywhere that air enters passages but not available for ____
____ more efficient than shallow because less dead space. Dead space expired ____
Breathe
Alveolar dead space :
No blood to ____. ____ situation
• Air enters into the bronchi, but if not in respiratory structures the air isn't available for gas exchange ○ Breathe in deeply > increasing % of inhaled air that goes into alveoli spaces ○ Reducing the amount of anatomical dead space • If taking a shallow breath, the air you exhale comes first from the \_\_\_\_ passages
gas exchange
deep breaths
first
alveolus
pathological
conducting
Blood only flows when pulmonary capillary pressure > alveolar pressure
Vertical lung – gravity and hydrostatic forces mean pulmonary arterial pressure subject to considerable ____
More blood towards ____ of lung than top
Standing upright creates problems for
____
• The lung was previously horizontal, and it changed shape > created problems for pulmonary blood flow • [???] ○ More blood at lower part of lung rather than the top
gradient
bottom
pulmonary blood flow
Zones of pulmonary blood flow
Blood only flows when
pulmonary capillary pressure > alveolar pressure
Zone 1: blood pressure less than ____ all the time. No ____. Not normal, but occurs if ____ drops e.g. after blood loss
Zone 2: alveolar pressure greater than ____ but less than ____ blood pressure. Blood flows ____
Zone 3, Blood pressure greater than ____ all the time. Blood flows ____
PA = alveolar pressure Pa = artery pressure Pv= venous pressure
• Zone 1 ○ \_\_\_\_ of the lung ○ Blood pressure is less than alveolar pressure always ○ No blood flow into the apex of the lung ○ Most people will have no zone 1 in their lungs; this is \_\_\_\_ § Will be seen in drop in arterial pressure, where you lost a lot of lung • Zone 2 ○ Middle portion of lung ○ Alveolar pressure is greater than diastolic, but less than systolic § Blood flows into the lung sometimes - intermittent • Zone 3 ○ Bottom of lung ○ BP > alveolar pressure throughout the entire cycle § Blood flows continuously
alveolar pressure
blood flow
arterial pressure
diastolic
systolic
intermittent
alveolar pressure
continuously
apex
abnormal
Zones of pulmonary blood flow
Capillaries are ____ by blood pressure and ____ by alveolar air pressure
Zone 1: No blood flow during any part of the cardiac cycle; alveolar pressure > ____. ____
Zone 2: Intermittent blood flow only during ____ peak pressure
Zone 3: Continuous blood flow; ____ always > than alveolar pressure
distended
contracted
capillary pressure
RARE
systolic
capillary pressure
Pulmonary blood pressure in exercise
Blood flow to lungs increased ____ with heavy exercise because:
- Increasing # of ____
- Increasing ____ to double ____ through capillaries
- Increased ____
Together, moderate rise in pulmonary arterial pressure
• Less ____ on heart
• Prevents ____ in lungs
7x open capillaries diameter rate of flow pulmonary arterial pressure
strain
edema
