Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Term 2: Pulmonary > Respiration, Ventilation, & Perfusion > Flashcards

Respiration, Ventilation, & Perfusion Flashcards

1
Q

At end of normal inspiration, what pressure is most negative?

A

-intrapleural

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is transmural/transpulmonary pressure?

A
  • the pressure that is overall acting on the alveoli

- relationship between the pressure of air in the alveoli and the intrapleural pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the equation for transmural pressure?

A

-PTM = PA – PIP

= Alveolar pressure - intrapleural pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is alveolar interdependence?

A

-the pressure at the pleural surface is transmitted through the alveolar walls to more centrally located alveoli and small airways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

If alveolar pressure is + when compared to atmospheric pressure, what is most likely occurring?

A

-expiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What must respiratory muscles overcome for ventilation to occur?

A
  • pressure gradient
  • mechanical properties
    • Compliance
    • Resistance of airways
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is compliance?

A
  • the distensibility of the lung and chest wall

- kind of like elasticity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the equation for compliance?

A

-CL = V / PTP

= change in volume over change in pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the normal compliance of the human lung?

A

-200mL/cm H2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is compliance related to the elastance of the lungs?

A
  • elastance is the reciprocal of compliance

- high compliance means low elastance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What determines pulmonary compliance?

A
  • compliance of lung

- compliance of chest wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What determines compliance of the lung?

A
  • elastic recoil

- surface tension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the physiologic advantages of surfactant?

A
  • it increases the compliance thus decreasing the work of breathing
  • stabilizes alveoli
  • keeps alveoli “dry”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is hysteresis and why does it occur?

A
  • the difference in the pressure/volume curve during inspiration and expiration
  • caused by difference in compliance in inspiration vs expiration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is functional residual capacity (FRC)?

A
  • the volume of the lung when the opposing forces of the chest wall wanting to expand and the lung wanting to collapse are equal and opposite
  • airway pressure = zero
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does emphysema affect compliance?

A
  • increases compliance and decreases elastance

- less pressure needed to increase volume of lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does fibrosis affect compliance?

A

-decreases compliance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What pathologies increase compliance?

A
  • emphysema

- aging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What pathologies decrease compliance?

A
  • pulmonary fibrosis
  • pulmonary edema
  • increased pulmonary venous pressure
  • Acute Respiratory Distress Syndrome (ARDS_
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the equation for pulmonary resistance?

A

-Q = change in P / R

Airflow = pressure gradient / resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What influences resistance in the lungs?

A
  • Airway radius**
  • muscle tone
  • lung volume
  • Viscosity of gas inhaled
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is Poiseuille’s Law?

A
  • a law for the resistance of an airway that takes into account the:
  • viscosity of the gas
  • the length of the tube
  • and the radius of the tube
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What prevents airway collapse in normal forced expiration?

A

-the positive transmural pressure

24
Q

Where is the site of greatest resistance in the airway?

A

-medium sized bronchi

25
Q

What is minute ventilation? What is its formula?

A

-The total air moved in and out of lungs per minute

Ve = Tidal volume X frequency

26
Q

What is alveolar dead space?

A
  • ventilated areas that are not well perfused
  • wasted ventilation
  • no gas exchange can occur
27
Q

What makes up physiologic dead space?

A
  • the combination of anatomic dead space and alveolar dead space
  • in healthy individual, physiologic dead space is equal to anatomic dead space.
28
Q

How do you calculate Alveolar Ventilation?

A

-the difference between the tidal volume and dead space volume, multiplied by the breathing frequency

29
Q

How do we estimate physiologic dead space?

A
  • based on the measurement of CO2 in mixed expired air

- there’s pretty much no CO2 in inspired air

30
Q

How do we know that the Partial Pressure of alveolar CO2 is?

A

-measure in arterial blood, assuming alveolar CO2 is roughly equal to arterail CO2 (40mmHg)

31
Q

What is the alveolar ventilation equation?

A

-PACO2= 0.863 x VCO2 / VA

32
Q

What is the normal VCO2?

A

-200 ml/min

33
Q

What is the body’s ideal PaCO2? (Arterial)

A

-40 mmHg

34
Q

What does the alveolar gas equation describe?

A

-it is used to predict the alveolar PO2

35
Q

What is the alveolar gas equation?

A

-PA O2 = (Pb – PH20) (F02) – PaC02 /R

R = 0.8

36
Q

What is the respiratory exchange ratio?

A
  • reflects the metabolism of body tissues in a steady state

- R = Vco2/Vo2

37
Q

What does A and a stand for?

A

A = alveoli

a = arterial

38
Q

What are the differences between pulmonary and systemic circulation?

A
  • Pulmonary circulation has higher capacity

- Pulmonary circulation has lower resistance and pressure than systemic circulation

39
Q

What is the equation for pulmonary vascular resistance?

A
  • R = (delta)P/Q

- Resistance equals pressure gradient between pulmonary artery and left atrium, divided by the cardiac output

40
Q

What happens to pulmonary vascular resistance as cardiac output increases, such as during exercise?

A

-it decreases so that the mean pulmonary pressure increases only slightly

41
Q

How is pulmonary vascular resistance decreased?

A

–recruitment of previously closed pulmonary vessels

-distension of existing open vessels

42
Q

What happens to total pulmonary resistance during inspiration?

A
  • it increases
  • remember that the total pulmonary resistance is the resistance of alveolar blood vessels plus resistance in the extra alveolar blood vessels. The resistance in the extra alveolar blood vessels will decrease, but the resistance in the alveolar blood vessels will increase proportionately more. Thus the overall increase in total pulmonary vessel resistance will increase.
43
Q

What happens to resistance in the extra-alveolar blood vessels during inspiration?

A
  • it decreases

- more negative intrapleural pressure pulls open extra-alveolar vessels

44
Q

What happens when alveolar O2 decreases?

A

-hypoxic vasoconstrictiction

45
Q

What is the purpose of hypoxic vasoconstriction?

A
  • to reduce blood flow to poorly ventilated alveoli

- this increases the perfusion to well-ventilated areas that allow for greater gas exchange

46
Q

What is the mechanism of hypoxic vasoconstriction?

A
  • poorly understood
  • hypothesis is that lower levels of alveolar O2 are sensed, triggering Ca entrance into muscle cells leading to vasoconsriction
  • also possible inhibition of nitric oxide synthase
47
Q

What influences the distribution of blood flow in the lung?

A
  • gravitational effects
  • hydrostatic pressures within the blood vessels
  • regional ventilation-perfusion matching
48
Q

Where is perfusion of the lung higher?

A
  • base of lung (while standing)

- Posterior lung (while supine)

49
Q

What is P-out in the lung in relation to blood flow?

A

-alveolar pressure

50
Q

Why is zone 1 of the lung considered dead space?

A
  • Alveolar pressure is very high, causing compression of the pulmonary capilliaries
  • though, the arterial pressure is still just high enough to perfuse, just at a lower rate
51
Q

What is the normal V/Q ratio in an adult lung?

A
  • 0.8

- this means we breath 20% less air by volume than blod flows through the lungs

52
Q

Where in the lung is matching of perfusion and ventilation the best?

A

-Zone2 (middle lung)

53
Q

What is an area of the lung that is not ventilated called, but has good perfusion?

A

-Alveolar Shunt

54
Q

What is the body’s compensation for a shunt?

A

-Hypoxic vasoconstriction

55
Q

What is the A-a gradient?

A

-the difference between alveolar oxygen and arterial oxygen

56
Q

What determines alveolar PO2 and PCO2?

A

-the relationship between alveolar ventilation and pulmonary capillary perfusion

57
Q

what is an anatomic shunt?

A

-when cardiac output bypasses the pulmonary circulation

Term 2: Pulmonary (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions