Physiology Respiratory Sukoawsi 1 Flashcards

(62 cards)

1
Q

What are the muscle used for rested inspiration? for forced?

A

Rested- Diaphragm and External Interncostals

Forced- Accessory muscles in teh neck, thorax, and abdominal cavities

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2
Q

What are the muscles used in rested expriration? Foreced?

A

rested- None, passive elastic recoil

Forced: Internal Intercostals, neck, and abdominal muscles

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3
Q

Definition of elastic

A

ability to spring back and resist deformation

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4
Q

Definition of Compliance

A

ability to yeild and be nonresistant (distensibility)

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5
Q

Definition of recoil

A

Ability to rebound or spring back

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6
Q

relation of recoil and compliance

A

The higher the compliance, the lower the recoil (mush ball)- Obstructive disease, emphysema,

The lower the compliance, the higher the recoil (golf ball), Restrictive disease

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7
Q

Examples of Obstructive lung diseases

A

Increased Resistance
Asthma
Bronchitis
Emphysema

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8
Q

Examples of Restrictive lung disease

A

Decreased compliance (higher recoil)
Diffuse Interstitial Fibrosis
Pulmonary Edema

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9
Q

Type A vs Type B COPD

A

Type A- symptoms of Emphysema (man culprit is cigarette smoking, alpha 1 antitrypsin deficiency)

Type B- symptoms of chronic bronchitis

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10
Q

What are clinical features of emphysema

A

HypoxemiaL milkd (PaO2 = ~80)

(A-a) PO2 = 10-15 (normal is

Hypercapnia: None

Acid-base problems: None as long as PaCO2 is normal

Tissue oxygenation: Normal

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11
Q

What is a “pink puffer”

A

Type A COPD

PaO2 - slighly reduced (~80)
PaCO2- normal

Acts like dead space
enough O2 in blood (pink)
needs to breathe more to maintain normal O2 and PaCO2 (puffer)

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12
Q

Chronic Bronchitis

A

Type B COPD
Narrowing of airwasy caused by hypersecretion of mucous and thickening of walls of respiratory tree

Chief culprit is smoking

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13
Q

Clinical Features of Type B COPD (chronic bronchitis)

A

Peristent, productive cough

Hypoxemia : Significatn to severe (PaO2= 40-70)

A-a PO2 ( 20-50)

Hypercapnia: Moderate (PaCo2=~50)

Acid-Base Disorder: mild to moderate acidosis

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14
Q

What is a blue-bloater

A

Decreased arteriolar PO2

Increased PCO2

May show signs of fluid retention with dependent edema

Acts like shunt

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15
Q

What potentiates Hypoxic Vasoconstriction

A

Decreased blood pH

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16
Q

What is the primary diorder in pulmonary blood flow

A

High V/Q ratio

theoretically, hypoxia shouldn’t develop,but often does

Diffusion impairment in areas with high flows

Pulmonary shunts develop

  • Opnieng AV anastomoses
  • blood though areas of hemorrhagic atelectasis
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17
Q

Clinical of Pulonary emoblism

A

PaCO2: Normal or mild hypocapnia

Acid-base disorder: None or mile alkalosis

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18
Q

What is Absorption Atelectasis

A

Occluded airway ,
Nitrogen is poorly soluble in plasma, and thus remains in high concentration in alveolar gas. If the proximal airways are obstructed, for example by mucus plugs, the gases in the alveoli gradually empty into the blood along the concentration gradient, and are not replenished: the alveoli collapse, a process known as atelectasis. This is limited by the sluggish diffusion of Nitrogen. If nitrogen is replaced by another gas, that is if it is actively “washed out” of the lung by either breathing high concentrations of oxygen, or combining oxygen with more soluble nitrous oxide in anesthesia, the process of absorption atelectasis is accelerated. It is important to realize that alveoli in dependent regions, with low V/Q ratios, are particularly vulnerable to collapse.

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19
Q

How do you treat Absorption Atelectasis

A

Problem can be minimezed by regularly hyperinflating lungs during anesthesia (a sigh) or by PEEP (positive and expiratory pressure)

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20
Q

What are static characteristics of respiration

A

Compliance and Recoil

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21
Q

What is equation of compliance

A

Change in volumepressure

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22
Q

What are two factors of recoil

A
  1. Recoil due to surface tension (major part of recoil force of lung)
    - reduced by surfactant but not elimated (80%)
  2. Recoil due to tissue elastic elements (Elastin, collagen, etc) 20%
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23
Q

What are the dynamic characterisitcs of respiration

A
  1. Resistance to airflow due to airway resistance (AWR) - 80%
  2. Resistance to airflow due to tissue frictional or viscour resistance (20%)
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24
Q

What detemrines airlow/ AWR

A
  1. flow rate
  2. flow pattern (diameter of airways and branching)
  3. Density
  4. Viscosity
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25
What determines Flow rate?
1. recoil pressure (determined by lung volume and compliance) 2. AWR
26
What are factors that increase compliance (easier to inflate)
Emphysema Asthma Age Asthma
27
Decreased Compliance (harder to inflate)
Fibrosis Edema High pulmonary venous pressure Lack of surfactant Increased recoil
28
Definition of Ventilation
Movement of flow of air form outside through air passages to terminal respiratory units (alveoli)
29
What determines the amt of ventilation (
1. Distensibility of lungs (compliance) 2. Factors that govern air movement - Muscular effort required to enlarge thorax and lungs, thereby generating a pressure differnce to drive air flow AWR impedes air flow
30
What par tof lung receives greatest ventilation? Why?
Bottom of lung receives the greates ventialtion when one spires from FRC 1. diferent IP P vertically, with top alveoli experiecning a more negative pressure holding them open before inspritation . Top alveoli has less reserve to enlarge 2. Weight of lung compresses lower alveoli. With inspriationa nd lowering dipahram, elastic componens of lung reduces this effect 3. Sum of all factors places lower lugn ona more favorable segment of the compliance curve at FRC
31
What is surface tension
at he air-liquid interphase inside the lung; tends to collapse the lung to a smaller volume
32
What is LaPlace's Law
Pressure (inside) = (2xST) / Radius
33
What is responsible fo tissue elastic recoil?
Geometric arrangement of elastin and collagen fibers COnsider effects on compliance of lung fibrosis or elastin changes seen with aging
34
Are alveoli bigger at base or apex of lung? WHy
At apex (top) they are bigger. The alveoli are smaller at the base b/c of gravity The Bottom of the lung has a higher negative pressure (more positive) than top of lung
35
Where d you meaures P-V bevavior in a pateint
in teh esophagus! Place small balloon in esophagus and measure pressure
36
What is the normal compliance of the lung
1000/5 = 200 ml/cm H20
37
What needs to happen to intrapleural pressure in ordr for lungs to expand?
Intrapleural pressure needs to decerase so lungs can expand
38
Which alveoli are more compliant, larger or smaller alveoli?
Smaller alveoli at the bottom! Using LaPlace's Law , where Presssure is lower with smaller radius (smaller alveoli)
39
What is responsible for elasticity/ compliance of lung?
1. geometry of fibers | 2. Surface tension
40
In a closed thorax, what is responsible for negative IP pressure at FRC
elastic recoil of chest wall outward Lung recoil inweard
41
What happens to IP Pressure duing forced expiration? Forced inspriaton?
Forced expiration- IP more positive at FRC Forced inspiration- IP more negative at FRC
42
What is the units of measurement used for ST
Dynes/cm
43
What do pressure-volue curves describe
lugn compliance at different lung volumes and show HYSTERESIS
44
What does difference in compliance depnd on
level in lung at any one lung volume at FRC (after normal expiration)
45
what happens to small airways athe base of lung at !0% Vital Capcity or less? At RV (after forced expiration)
small airways at the base of lung CLOSE b/c of the POSITIV PRESSSURE (intraplural), trapping air in teh distal alveoli This CLOSING VOLUME increases with age and disease
46
What is the PRIMARY factor that causes static recoil of lungs?
Surface Tension
47
What kind of cells produce surfactant
Type II alveolar Cells
48
What does Surfactant do to surface tension? What molecule?
Reduces ST and stabilizes lung alveoli Surfactant contains DPP , detegent synthesized by FFAs and other These cause HYSTERESIS seen in compliance curves
49
What does impedence of blood flow to a region do to surfactant synthesis
It prevents surfactant synthesis
50
What are the functions of Surfactant (3)
1. Increases Compliance (makes it easier to inflate lungs) 2. Surfacatant keeps lung dry/reduces tendency of alveolar edema (reduces forces that "pull" fluid out of capillary" 3. Increases Alveolar stability (less likely that smaller alveoli empty into larger alveoli)
51
How does surfactant reduce tendency of alveolar edema
B/c without surfactant, alveoli with lining layer --> alveolus contracts due to high ST Pressure --> reduces pressure around capillaries of alvelar wall --> edema moves out Interdependence also increases alveolar stability and eeps pressure low around large BV and airways as sthe lung epands. This ist eh site of early edema
52
Loss of surfacatnat results in (3)
1. Stiff lungs (elevated surface tenson) 2. Areas of atelectasis 3 Alveoli filled iwth fluid
53
How does surfactatn keep lungs dry? Whawt happens without surfactant?
Lack of surfactant increases ST of the alveolus, drawing the alveolar walls inward (recoil) This causes greater negative interstitial space, overcoming colloid osmotic pressure (COP) of blood, resulting in more fluid filtering out of capillaries into interstiial space and into alveoli
54
What happens to surfactant in premature inants
Lack of surfactatn resuts in infant respiratory distress syndrome Similar condition exists in adutls nad is called Adult Respiratory Distress Syndrom (ARDS)
55
What are factors that increase compliance (easier to inflate)
Emphysema Age Asthma
56
Decreased Compliance (harder to inflate)
Fibrosis Edema High pulmonary venous pressure Lack of surfactant
57
Definition of Ventilation
Movement of flow of air form outside through air passages to terminal respiratory units (alveoli)
58
What determines the amt of ventilation (
1. Distensibility of lungs (compliance) 2. Factors that govern air movement - Muscular effort required to enlarge thorax and lungs, thereby generating a pressure differnce to drive air flow AWR impedes air flow
59
What par tof lung receives greatest ventilation at FRC? Why?
Bottom of lung receives the greates ventialtion when one spires from FRC 1. diferent IP P vertically, with top alveoli experiecning a more negative pressure holding them open before inspritation . Top alveoli has less reserve to enlarge 2. Weight of lung compresses lower alveoli. With inspriationa nd lowering dipahram, elastic componens of lung reduces this effect 3. Sum of all factors places lower lugn ona more favorable segment of the compliance curve at FRC
60
Which lung gets more ventialtion at RV? Why?
Upper lungs receive greateest venitaltion intiially! Small airways (Respiratory bronchioles) in teh bottom of lung close as one exhales and approacehs RV Restuls in air trapping in lower lunga nd greater precetnatge of expired air coming from uper protions of lung at eh end of a forced expiration to RV With age, lugns more compliant, closure of small aiways occurs at higher lung ovluems (even at FRC)
61
Chest wall and lungs- relaxation curve
Chest wall and lungs each attempt to recoil to their lowest free energy equilibrium position
62
What is chest walla and lungs at FRC
outwards at FRC for chest wall Inward at FRC for lungs FRC is determined when the two reocil forces balane each other