Unit 6 - Respiratory System Flashcards Preview

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Flashcards in Unit 6 - Respiratory System Deck (80)
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1
Q

What are the two membranes of the pleura?

A
  1. Parietal pleura

2. Visceral pleura (against the lungs)

2
Q

What is the space called between the parietal and visceral pleura?

A

Pleural space

- contains a little fluid

3
Q

What is each lung surrounded by?

A

Pleural cavity

4
Q

What are the functions of the pleurae and pleural fluid (3)?

A
  1. Reduction of friction
  2. Creation of pressure gradient
  3. Compartmentalization
5
Q

Regarding the atmospheric, pleural and alveolar pressures, which is greatest? which is lowest?

A

P(atm) > P(alv) > P(pl)

6
Q

Why is it important that atmospheric pressure is greater than alveolar pressure?

A

So we can breathe in!

- pressure goes from HIGH to LOW

7
Q

Why doesn’t the atmospheric pressure collapse the lungs?

A

Because of pleural pressure

- pleural pressure is lower than alveolar pressure and keeps the alveoli INFLATED

8
Q

Why might breathing become impossible if there is inflammation of the pleura?

A

This would increase the pressure of the pleura, collapsing the alveoli

9
Q

What is the benefit of compartmentalization of the lungs?

A

Helps to prevent/reduce the spread of infection

10
Q

What does the upper respiratory tract consist of (3)?

A
  1. Nasopharynx
  2. Oropharynx
  3. Larynx
    (Sometimes trachea is included too)
11
Q

What does the lower respiratory tract consist of (4)?

A
  1. Trachea
  2. L and R primary bronchi
  3. Bronchioles
  4. Lungs
12
Q

What is extrathoracic? (Where is it?)

A

Trachea and UP!

13
Q

What is intrathoracic?

Where is it?

A

Bronchi and DOWN!

14
Q

What are the 3 functions of the upper respiratory tract?

A
  1. Filters incoming air
  2. Humidifies incoming air
  3. Warms incoming air
15
Q

Why is it important that air is humidified on the way INTO the lungs?

A

So that when you exhale air from the lungs, you don’t lose any more moisture

16
Q

What does the tracheobronchial tress consist of?

A
  1. Trachea
  2. Bronchi
  3. Terminal bronchioles
    - 23-28 branches of conducting tubes
17
Q

How are conducting tubes different than alveoli?

A

Conducting tubes cannot exchange air between the blood and the airway

18
Q

Where along the respiratory tract is smooth muscle present?

A

Wall of the bronchi and bronchioles
- amount of smooth muscles increases distally to the small bronchi then decreases and is eventually absent at the respiratory bronchioles

19
Q

Where along the respiratory tract is cartilage present?

A

In the wall of the trachea and bronchi

- amount of cartilage decreases distally and disappears in the terminal bronchioles

20
Q

What does smooth muscle in the wall of the bronchi and bronchioles help to control?

A

Airway conductance

21
Q

What is the functional role of the smooth muscle around the airways?

A

Prevent inhalation of toxic, pollen, dust, etc.
- If there is an irritant in the air (smoke, dust, glass particles), if the airways don’t constrict, the person will suffer a lot of damage to the airways

22
Q

What is the role of tracheobronchial epithelium?

A

Mucus-secreting ciliated epithelium

  • Traps particles
  • Cilia beat to expel trapped particles
23
Q

What happens to tracheobronchial epithelium if you are a chronic smoker?

A

Metaplasia: epithelium

  • stratified squamous epithelium (cannot produce mucus)
  • higher risk of respiratory infections
  • ability to filter is reduced
24
Q

Where does gas exchange take place?

A
  • Respiratory bronchioles

- Alveoli

25
Q

What is the function of elastic and collagen fibers in alveoli?

A
Collagen = restricts stretch (can't over-inflate)
Alveoli = ability to recoil
26
Q

What happens to the connective tissue of alveoli in COPD (emphysema)?

A

Fibers are getting destroyed

  • ability to prevent over-inflation is lost as well as ability to recoil
  • alveoli get BIG!
27
Q

Describe the relationship between alveoli and blood vessels.

A

When an alveoli is open, there is blood flow.

When an alveoli is closed, the blood vessels collapse (poor blood flow through lungs)

28
Q

What facilitates gas exchange between the alveolar lumen and the blood?

A

Thin membrane

- intimate contact with a rich network of capillaries

29
Q

What do Type 1 alveolar cells do? What do they look like?

A

Simple squamous epithelium (FLAT CELLS)

- facilitates diffusion of gases between bloodstream and alveoli)

30
Q

What do Type 2 alveolar cells do? What do they look like?

A

Cuboidal (septal) cells

- secrete surfactant

31
Q

What do alveolar macrophages do? What is another name for them?

A

Engulf foreign particles in the lungs

- also called dust cells

32
Q

How thick is the endothelium of the capillaries and the alveolar epithelium combined?

A
  1. 1 - 1.5 MICRO meters

- allows for optimal diffusion of oxygen and carbon dioxide

33
Q

How does pneumonia affect diffusion across the alveolar epithelium?

A

Fluid is in alveoli

  • increases thickness of the membrane
  • makes it harder for gases to diffuse across
34
Q

What are the 4 normal respiratory functions?

A
  1. Alveolar ventilation
  2. Alveolar perfusion
  3. Alveolar-capillary diffusion
  4. Gas transport in circulation
35
Q

What is ventilation?

A

The act of driving air in and out of the lungs

36
Q

What is perfusion?

A

Adequate blood supply to the alveoli

37
Q

What is diffusion?

A

Gas movement (down concentration gradients) from alveolar space to blood

38
Q

Lung ventilation is dependent on which two things?

A
  1. Lung compliance

2. Action of respiratory muscles - (chest compliance)

39
Q

What is chest compliance?

A

Allows the chest to be expanded

40
Q

What is lung compliance?

A

Allows the lungs to be expanded

41
Q

What are the two main muscles of ventilation?

A
  1. Diaphragm

2. External Intercostal muscles

42
Q

What happens when the diaphragm contracts?

A

It pulls DOWNWARD

  • increasing the volume of the chest
  • pressure in chest decreases
43
Q

What are the accessory muscles of inhalation (forced inhalation)?

A
  1. Scalene

2. Sternocleidomastoid

44
Q

What are the accessory muscles of exhalation (forced exhalation)?

A
  1. Internal intercostals

2. Abdominal muscles

45
Q

True or False:

During quiet breathing only inhalation requires energy

A

True

- muscles that assist in exhalation are only used during FORCED exhalation

46
Q

Describe the mechanics of ventilation

A
  1. Contraction of diaphragm increase volume of thoracic cavity (pulled downwards)
  2. Contraction of external intercostals raises ribs
47
Q

What is tidal volume?

A

Normal breath in and out

= approx 500 mL

48
Q

Describe inspiratory reserve volume

A

Volume you can force IN at the end of the normal inhalation

= approx 3100 mL

49
Q

Describe expiratory reserve volume

A

Volume that you can force OUT at the end of a normal exhalation
= approx 1100 mL

50
Q

What is the residual volume?

A

Volume that is leftover inside the lungs after a forced exhalation

51
Q

What is the vital capacity? How is it calculated?

A

Maximum capacity that you can inhale and exhale (tidal volume + inspiratory and expiratory reserve volumes)

52
Q

What is the total lung capacity?

A

Maximum amount of air that the lungs can contain

53
Q

What is the forced expiratory volume (FEV) used for?

A

Used to determine if a patient has an obstructive pulmonary disorder

54
Q

How is FEV calculated (forced expiratory volume)? In a healthy adult, what should this number be?

A

% of vital capacity exhaled over time

- 75%-85% in 1 sec

55
Q

How is the minute respiratory volume (MRV) calculated?

A

Amount of air drawn into the lungs in 1 minute

= Tidal volume x RR

56
Q

What is the ratio between ventilation and perfusion?

A

1: 1
- maintained even if we are exercising
- IF there is a mismatch in the ration, there is a problem with ventilation or circulation

57
Q

How easy it is for the lungs to inflate is dependent on what 3 things?

A
  1. Elastin and collagen fibres
  2. Water content
  3. Surface tension
58
Q

What do elastin and collagen fibres do for the lungs?

A
Elastin = ability to recoil
Collagen = prevent over inflation
59
Q

What happens if there is too much water content in the lungs?

A

More water = harder to breathe

- it is easier to inflate a lung that is NOT filled with water

60
Q

Why does water have a high surface tension?

A

Because of the hydrogen bonds between the molecules

61
Q

What does surfactant do in the lungs? How?

A

Reduces surface tension

- acts as a mechanism to break apart some of the hydrogen bonds in H2O

62
Q

Why is it that babies who are born prematurely have a hard time breathing?

A

Because surfactant is developed VERY late in pregnancy

- preemies don’t have a lot of it (or ANY!)

63
Q

True or False:

Anything that increases the thickness of the membrane of the alveoli will decrease diffusion

A

True

- compromises gas exchange

64
Q

What factors affect alveolar-capillary diffusion (3)?

A
  1. Permeability
  2. Surface area
  3. Concentration gradient of the gas
65
Q

What is the normal partial pressure of oxygen in the blood?

A

80 mmHg (arterial blood)

66
Q

What is the normal range for the amount of oxygen that is bound to hemoglobin (oxyhemoglobin levels)?

A

97 - 99%

- 95% saturation is acceptable in subjects with normal hemoglobin levels

67
Q

What happens to the binding of oxygen to hemoglobin as partial pressure of oxygen increases?

A

Binding levels increase too

when partial pressure is low, oxygen saturation and binding is low

68
Q

As partial pressure increases, will oxygen saturation level ALWAYS increase?

A

NO!

= there is a maximum level of oxygen saturation (100%)

69
Q

What is easier to measure, oxygen saturation or partial pressure of oxygen?

A

Oxygen saturation

70
Q

If the oxygen saturation level is 98%, what SHOULD the partial pressure of oxygen be?

A

80 mmHg

71
Q

What is the normal partial pressure of carbon dioxide in arterial blood?

A

35 - 45 mmHg

72
Q

What is the most common form that carbon dioxide is transported in, in the body?

A

Bicarbonate ion

Carbonic acid Bicarbonate ion + H+ ion

73
Q

What happens to carbon dioxide levels as you breathe out?

A
  • decrease levels of CO2

- decrease levels of carbonic acid, raising your blood pH

74
Q

What is the function of CENTRAL chemoreceptors?

A
  • measures partial pressure of CO2 and pH in cerebrospinal fluid
75
Q

When do the central chemoreceptors increase respirations?

A
  1. When PCO2 increases OR

2. pH decreases (more acidic)

76
Q

What happens if chemoreceptors are exposed to the same stimulus over an extended period of time?

A

They adapt

- become less sensitive to the stimulus

77
Q

What is the function of PERIPHERAL chemoreceptors?

A

Measure partial pressure of oxygen in the arterial blood

78
Q

When do periopheral chemoreceptors increase respirations?

A

When partial pressure of oxygen is < 60 mmHg

79
Q

What is more influential in affecting/regulating breathing - CO2 or O2?

A

CO2 (central chemoreceptors)

- if there is an adaptation of central chemoreceptors, peripheral receptors will take over

80
Q

Which receptors (central or peripheral) are FASTER but not as strong at regulating breathing?

A

Peripheral