Gas Exchange 1 Flashcards

1
Q

What is in the air

A

78% Nitrogen
21% Oxygen
0.9% Argon
0.037% CO2

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2
Q

What is an important variable in respiratory gas exchange

A

Rate of diffusion

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3
Q

Diffusion of gas is influenced by: (5 items)

A
Solubility of the gas in the medium (water, air)
Partial pressure gradient
Temperature
Distance for diffusion
Surface area for diffusion
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4
Q

What is the Fick equation?

A

Rate of diffusion = Diffusion coefficient * SArea * Pressure gradient

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5
Q

Rate of diffusion is smallest when ___

A

The distance is at its smallest

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6
Q

What is the diffusion coefficient

A

Index of ease of diffusion of a particular substance through a given medium

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7
Q

The diffusion coefficient depends on what

A

Temperature and solubility

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8
Q

The pressure of the gas is a measure of ____

A

the thermodynamic activity of the gas molecules

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9
Q

Dalton’s Law of Pressures

A

Each gas exerts its own partial pressure. The sum of the partial pressures = total pressure and is proportional to the total number of gas molecules

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10
Q

What is the Ideal gas law?

A

PV=nRT

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11
Q

What is P equivalent to in the Ideal gas law?

A

P=(nRT)/V

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12
Q

Partial pressure depends on ___

A

Temperature of the gas

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13
Q

If the temperature increases and volume is not constant, what will happen?

A

The volume will increase & pressure stays constant & concentration of gas decreases

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14
Q

If temperature increases and volume is constant, what will happen?

A

Pressure increases & concentration of gas stays the same

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15
Q

What does a gas need to do before it diffuses into a cell?

A

Dissolve into the liquid

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16
Q

The amount of gas that will dissolve in a liquid is dependent on ___

A

Partial pressure in air & solubility in the liquid

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17
Q

What is Henry’s Law

A

Concentration of gas dissolved in liquid = Partial pressure of gas in atmosphere * Solubility of gas in liquid

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18
Q

What has a large effect on solubility of gases in liquids?

A

Temperature & salinity

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19
Q

What is Graham’s Law

A

Diffusion of a gas in a liquid is proportional to its solubility & inversely proportional to the square root of its molecular weight

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20
Q

Which diffuses faster in air: O2 or CO2

A

O2 is 1.2 faster to diffuse than CO2

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21
Q

Which is more soluble in water: O2 or CO2

A

CO2 is 24 times more soluble in water than O2

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22
Q

Which is more soluble in air: O2 or CO2

A

Same

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23
Q

Which has higher molecular weight: O2 or CO2

A

CO2

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24
Q

What is the diffusion rate for oxygen in water vs. air

A

Diffusion rate for O2 in water is 300,000 times more slower than air

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25
Q

What direction is O2 gradient in terms of the body

A

Into the body

26
Q

What direction is the CO2 gradient in terms of the body

A

Out of the body

27
Q

Characteristics of gas exchange organs

A

Must be moist so that gases can dissolve into liquid

28
Q

How does the body compensate for slow O2 diffusion rates in liquid

A

Circulatory system & O2 transport molecules & O2 binding molecules

29
Q

What is hemoglobin

A

O2 transport molecule

30
Q

What is myoglobin

A

O2 binding molecule

31
Q

Why is medium (air or water) flow over respiratory surfaces greater in water breathing than in air breathing animals

A

Because water has a much lower concentration of O2 than air

32
Q

What is dessication

A

When the respiratory surface becomes dry

33
Q

What are problems for water breathing animals

A

Have to expend more energy to move more medium (water) over the gas exchange organ

34
Q

What are problems for air breathing animals

A

Have to keep respiratory surfaces moist to prevent dessication. Water is lost by evaporation

35
Q

How can you deliver O2 directly to internal cells and tissues

A

Bulk flow of water or air

36
Q

3 types of ventilation

A
  1. Nondirectional ventilation (wave gills in medium)
  2. Tidal ventilation (lungs)
  3. Unidirectional ventilation (fish gills)
37
Q

What happens in tidal ventilation

A
  • Bidirectional movement
  • As Po2 in blood increases, Po2 of medium decreases
  • Not the most efficient, but prevents dessication
38
Q

Why is unidirectional ventilation good

A

Makes greater exchange efficiency because blood is always exposed to O2-rich medium

39
Q

The fish gill is an example of what type of flow

A

Countercurrent (best exchange efficiency)

40
Q

What is special about Teleost fish

A

They combine directional flow with concurrent exchange

41
Q

How do birds maximize gas exchange

A

They implement a crosscurrent mechanism

42
Q

What gas exchange organ do birds have

A

Stiff, hexagonal lungs and air sacs

43
Q

What flow type do bird respiratory systems implement

A

Unidirectional & continuous flow

44
Q

Where do the lungs end

A

Alveoli

45
Q

Two types of cells in alveoli

A

Type I & Type 2

46
Q

What do Type 1 cells do

A

Mainly for gas exchange

47
Q

What do Type 2 cells do

A

Release surfactant

48
Q

How is ventilation controlled in mammals

A

Contraction & relaxation of the diaphragm

49
Q

Diaphragm contracts when ___

A

You breath in

50
Q

Diaphragm relaxes when ___

A

You breath out

51
Q

What is tidal volume

A

The volume of air inhaled/exhaled with each breath

52
Q

How much is average tidal volume

A

500 mL

53
Q

What is vital capacity

A

Maximum tidal volume during forced breathing

54
Q

What is the vital capacity for females and males, respectively

A

3.4 L & 4.8 L

55
Q

Why don’t the alveoli in the lung collapse

A

Residual volume & Surfactant

56
Q

What is residual volume

A

Air that remains in the lungs after exhalation. The lungs hold more air than the vital capacity

57
Q

What is surfactant

A

A detergent (mixture of phospholipids and proteins) secreted by alveolar epithelium.

58
Q

What does surfactant do

A

Reduces surface tension in the liquid coating the alveolar surface

59
Q

What does surfactant increase

A

Compliance of alveoli

60
Q

What stimulates surfactant production

A

Corticosteroids