Brainscape's Knowledge GenomeTM

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


See full index

111: Anatomy/Phys 2 > 2.3 Mechanics of Breathing > Flashcards

2.3 Mechanics of Breathing Flashcards

1
Q

how are respiratory pressures described

A
  • relative to atmospheric pressure pressure exerted by air surrounging the body)

atm = 760 mm Hg

negative resp pressure: less than Patm

Positive resp pressure: greater than Patm

Zero resp pressure: equal to Patm

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

what is intrapulmonary pressue

A

– Pressure in alveoli (also called intra-alveolar pressure)

– Fluctuates with breathing and always eventually equalizes with Patm

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

what is intrapleural pressure

A

Pip

  • Pressure in pleural cavity (fluctuates with breathing)

** Always a negative pressure (

  • > Usually ~4 mm Hg less than Ppul
  • fluid level must be kept at a minimum -> excess is pumped out by lymphatic system
  • if fluid accumulates, positive Pip pressure develops and lung collapses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what promotes lung collapse

A

*tlaking about intrapleural pressue

  • two inward forces promtoe lung collape
    1. Lungs’ natural tendency to recoil because of elasticity *lungs want to assuem smallest size)
    2. Surface tension of alveolar fluid pulls on alveoli to try and reduce alveolar size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what forces promtoe lung collapse

A
  1. Lungs natural tendency to recoil bc of elastcity
  2. Surface tension`of alveolar fluid pulls on alveoli to try reduce alveolar size

* elasticity in chest wall pulls thorax outward (tends to enlarge lungs)

  • Negative Pip is affected by these opposing forces but is maintained by strong adhesive force between parietal and visceral pleurae

*thoracic cavity prevents it from collapse countering tendence to recoil and surface tension

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

What is transpulmonary presure

A

* ALWAYS -ve, usually -4 mmHg

  • raspulmonrary pressure = Ppul - Pip
  • pressure that keep lung spaced open and keeps lungs from collapse
  • greater transpulmonary pressure, the larger the lungs weill be -> more neg = larger lungs

• Negative Pip must be maintained to keep lungs inflated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Lungs will collapse if Pip = _____

A

• Pip =Ppul or Pip =Patm

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

what are the 4 pressues to know

A
  • atmospheric pressue Patm = 0 mmHg aka 760 mmHg

Intraplural pressure Pip -4mmHg (756 mmHg)

  • transpulmonary pressure 4mm Hg (diff between atm and -4mmHg)

intrapulmonary pressure Ppul mmHg

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

effects of changes in volume and changes in pressure on ventilation

A

– Volume changes lead to pressure changes
– Pressure changes lead to flow of gases to equalize pressure

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

boyles law

A

Gases always fill the container they are in
– Pressure (P) varies inversely with volume (V)

P1V1 = P2V2

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

describe quiet inspriation

A

Active process involving inspiratory muscles (diaphragm and external intercostals)

  • action of diaphragm: contracts and moved inferiorly, flattens -> INC thoracic voume

intercoastal muscles: external contract, rib cage is lifted up and out -> INC thoracic volume

  • lungs are stretched as they are pulled out with thoracic cage causing intrapulmonary pressure to drop by 1mmHg (becomes more negative

*Ppul < Patm

  • air flows into lungs, down its pressure gradient until Ppul = Patm
  • Pip lowers to 6mm Hg less than Patm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe forced deep inspirations

A
  • can occur during vigorous excercise or in ppl wtih COPD
  • activates accessory muscles: Scalenes, sternocleidomastoid, and pectoralis minor (plus external intecostals and diaphagm)

*Erector spinae muscles of back also help to straighten thoracic curvature

  • act to further inc thoracic cage size, create larger pressure gradient so more air is drawn in
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

describe quiet expiration,

A

typically passive

  • inspiratory msucles relax, thoracic cavity volume decreases and lungs recoil
  • Volume decrease causes intrapulmonary pressure (Ppul) to increase by +1 mm Hg
  • Ppul > Patm so air flows out of lungs down its pressure gradient until Ppul = Patm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe forced expiration

A

active process that uses oblique & transverse abdominal muscles, as well as internal intercostal muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

intrapulmonary and intrapleural pressure during ventilation

A
  • intrapulmonary:
    • inspiration: pressure inside lung decreases as lung volume increases
    • during expiration: pressure increases
  • intrapleiral pressure
    • inspiration: pleural caity pressure becomes more negative as chest wall expands
    • returns to intial vlaue as chest wall recoils
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

volume of breathe during ventilation

A

0.5L of air moves into and out of lungs in each breath

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

what are the factors that affect pulmonary ventilation

A
  • three physical factors the ease of air passage and amount of energy required for ventilation
  • ariway resitance
  • alveolar surface tension
  • lung compliance
18
Q

what is airway resistance

A
  • caused by frication: major nonelastic source of resistance to gas flow’ occurs in airways

Relationship between flow (F), pressure (deltaP) and resistance (R) F=P/R

*deltaP = pressure gradient btwn atm and alveoli

19
Q

why is airway resistance usually insignificant

A
  1. Diameters of airways in first part of conducting zone are huge
  2. progressive branching of airways as they get smaller leads to an increase in total croos sectional area
    - any resitance usually occurs in medium sized bronchi
    - resistance disappears at termianl bronchioles where diffusion is what drives gas movement
20
Q

describe alveolar suface tension

A
  • attraction of liquid molecules to one another at a gas-liquid interface
  • > tendsto draw liquid molecules closer together and reduce contact with dissimilar gas molecules
  • > Resists forces that increase surface area of liquid

*Water has a very high surface tension and tends to cause alveoli to shrink to smallest size/ collapse

21
Q

what is surfactant

what produces it

A

detergent-like lipid and protein complex that helps reduce alveolar surface tension of alveolar fluid

  • prevents alveolar collapse
  • produced by type II alveolar cells
22
Q

what is infant respiratory distress syndrome (IRDS)

how do you treat it?

A

Insufficient quantity of surfactant in premature infants

  • results in collapse of alveoli after each breath
  • treatment: spraying natural or synthetic surfactant into newborns air passages
  • > Positive pressue devices also help alveoli open betwen breaths
  • > severe cases may require mechanical ventilation

*Survivors of mechanical ventilation may develop bronchopulmonary dysplasia, chronic childhood lung disease

23
Q

describe lung compliance

A

Measure of change in lung volume w/ given change in transpulmonary pressure

*how much stretch lung has

  • norally high bc of distensibility of lung issue and surfactant (dec alveolar surface tension)

*high lung compliance means easier for lugns to expand

24
Q

mathematical representation of lung compliance

A

ΔCL =ΔVL/ Δ(Ppul - Pip)

ΔCL equals compliance

ΔVL equals change in lung volume,

Δ(Ppul - Pip) equals change in transpulmonary pressure

25
Q

how can lung compliance be diminished

A

Nonelastic scar tissue replacing lung tissue (fibrosis)

  • Reduced production of surfactant
  • Decreased flexibility of thoracic cage
26
Q

4 respiratory volumes

A
  • Tidal Volume (TV): amount of air moved intoa dn out of lung w/ each breath (500 mL)
  • Inspiratroy reserve volume (IRV): amount fo air that can be inspired forcible beyond the TV (2100-3200mL)

Expiratory Reserve Volume (ERV): amount of air that can be forcibly expelled from lungs (1000-1200mL)

Resideual Volume (RV): amount of air that always remains in lungs needed to keep alveoli open

27
Q

wha are respiratory capacties

A

Combinations of two or more respiratory volumes

28
Q

what is inspiratory capactity

A

Inspiratory capacity (IC): sum of TV + IRV

29
Q

what is Functional resideual capacity (FRC)

A

(FRC): sum of RV + ERV

30
Q

what is vital capacity

A

(VC): sum of TV + IRV + ERV

31
Q

what is total lung capacity

A

(TLC): sum of all lung volumes (TV + IRV+ ERV + RV)

32
Q

male vs female volume and capacity

A

tidal volume si the only thing thats the same in males and females

(amount of air moved in to and out of lung with each breath (~500ml)

33
Q

what are the dead spaced in the lung

A
  • Anatomical dead space:
    • does not contribute to gas exchange
    • Consists of air that remains in passageways ~150ml out of 500ml TV
  • Alveolar dead space
    • occurpied by nonfunctional alveoli
    • can be due to collapse or obstruction (not participating in gas exchange)
  • Total dead space
    • sum of anatomical and alveolar dead space
    • usually not a thing unless certain diseases
34
Q

what does spirometry distingusih between

A

*pulmonary function tests

  • Obstructive pulmonary disease: increased airway resistance (bronchitis)
    • TLC, FRC, RV may increase beacuse of hyperinflation of lugns
  • Restictive disease: reduced TLC due to disease (ex: tuberculosis) or exposure to environmental agents (fibrosis)
    • VC, TLC, FRC, RV decline because lung expansion is compromised
35
Q

what pulmonary function tests measure rate of gas movement

A
  • Forced vital capacity (FVC)
    • amount of gas forcibly expelled after taking deep breath
    • ie how fast you cn move air out
  • Forced expiratroy volume (FEV)
    • amount of gas expelled during specifc time interval of FVC
      • FEV1 measures gas expelled in 1st second
      • health ppl can expel 80% of FVC in 1st second
36
Q

EV value of patients with obstructive and restircutive disease

A

Obstrictive: exhale less than 80% in 1st second (associated w/ ability to get air out)

Restrictive: exhale 80% or more even with reduced FVC (associated with ability to get air in)

37
Q

what is minute ventilation

A

*alveolar ventilation

  • total amount of gas that flows into or out of respiratory tract in 1 minute
  • > normal at rest = ~ 6L/min
  • > Normal with exercise = up to 200 L/min
  • > only rough estimate of respiratroy efficiency
38
Q

what is Alveolar ventilation rate (AVR)

  • flow of gases into and out fo alveoli during a aprticular time

*better indictor of effective ventilation then mintue ventilation

A
  • flow of gases into and out fo alveoli during a aprticular time

*better indictor of effective ventilation then mintue ventilation

*takes into account amount of dead space, TV, and rate of breathing

39
Q

how do you calcular AVR

what affects it?

A

*aveolar ventilation rate

AVR = Frequency * (TV-dead space)

(mL/min) = (breaths/min) *(mL/beath)

  • > affected by TV and frequency bc dead space in an individual is normally constance
  • > significant inc in AVR are caused by INC TV rather than freq

*RAPID SHALLOW BREATHING CAN DECREASE AVR

40
Q
A
41
Q
A
42
Q

what would happen if you had a punctured parietal pleural vs ruptured visceral pleura

A
  • Punctured parietal pleura
    • pneumothorax (air in pleural cavity)
    • intraplural pressure becomes equal to atmospheric
      • intrapleural should be -4mmHg
  • Ruptured visceral pleura
    • ????

111: Anatomy/Phys 2 (31 decks)

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