Respiratory System Flashcards

1
Q

4 functions of nasal cavity

A
  1. Warms, cleans and humidifies inspired air
  2. Serve as resonating chambers for speech
  3. Sense of smell
  4. Open airway for ventilation
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2
Q

Structure of nasal cavity and paranasal sinuses

  • Epithelium?
  • Structures which help warm/humidify air? Where?
  • Divided in midline by?
  • Projections?
A
  • Lined w/ respiratory mucosa
  • blood vessels and seromucous glands beneath respiratory mucosa
  • nasal septum
  • 3 mucosa-covered projections: superior, middle + inferior terminate
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3
Q

What structures does the pharynx connect?

A
  1. Nasal cavity to the oral cavity

2. Larynx and the esophagus

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4
Q

3 regions of the pharynx + their position + their function

A
  1. Nasopharynx
    - posterior to nasal cavity
    - air passage
  2. Oropharynx
    - posterior to oral cavity
    - passage for food and air
  3. Laryngopharynx
    - inferior to the epiglottis
    - guides where food and air go to
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5
Q

3 functions of the larynx

A
  1. Provides open airway (prevents from collapse)
  2. conducts air
  3. Sound/voice production
  4. Diverts air and food in proper directions
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6
Q

Nose:

  • Within which structure?
  • Composed of which type of cartilage?
  • Function?
  • Which makes up the midline?
A
  • Nasal cavity
  • soft cartilages (lateral, alar and septal)
  • hold nose open, prevent from breaking
  • septal cartilage
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7
Q

Describe respiratory mucosa

A

pseudo-stratified, ciliated, columnar epithelium containing goblet cells.

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8
Q

What is the respiratory system and its main function?

A

A system of connected organs and structures that function to conduct warm, moist, clean air into close proximity with blood for gas exchange.

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9
Q

Which epithelium type lines most of the URT?

A

Respiratory mucosa: pseudo-stratified, ciliated, columnar epithelium containing goblet cells

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10
Q

What is the main function of the epiglottis?

A

Prevents food from going into the airway

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11
Q

Structures of the LRT?

A

Trachea
Bronchi
Bronchioles
Alveoli

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12
Q

3 functions of the trachea

A
  1. Maintain open airway for conduction of air
  2. Clean, warm and humidify inhaled air
  3. Cilia form the mucociliary escalator remove debris to the pharynx & redirects to the stomach
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13
Q

Structure of trachea

  • Position
  • Extends b/w
  • Epithelium
  • Structures w/in submucosa
  • Composition
A
  • Anterior to esophagus
  • Rigid tubular structure from larynx to primary bronchus
  • Lined w/ respiratory mucosa and seromucous glands in the submucosa
  • C-shaped rings of cartilage; smooth muscle posteriorly
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14
Q

Describe the bronchial tree and it’s levels.

Include pulmonary + bronchial circulation.

A
  • tubular structures w/ rings of cartilage to prevent collapse
  • Levels:
    1. Trachea (Lined w/ respiratory mucosa and seromucous glands)
    2. Primary bronchi (Lined w/ respiratory mucosa and seromucous glands)
    3. Secondary (lobar) bronchi (Lined w/ respiratory mucosa and seromucous glands)
    4. Tertiary (segmental) bronchi (Lined w/ respiratory mucosa and seromucous glands)
    5. Bronchioles (lack cartilage and submucosal glands; goblet cells start to disappear) - branch to form alveolar ducts and terminate in alveolar sacs
    6. Alveoli (flattened pneumocystis)

Pulmonary circulation supplies deoxygenated blood
Bronchial circulation perfuses the lung tissue w/ oxygenated blood from the systemic circulation.

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15
Q

How many lobes and fissures do each of the right and left lung have?

A

Right:
3 lobes, 2 fissures
Left:
2 lobes, 1 fissure

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16
Q

What are the surface cells of alveoli? What are their structure?

A
  • Type I pneumocytes: squamous

- Type II pneumocytes: cuboidal (surfactant-secreting; reduces surface tension)

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17
Q

What 2 features of alveoli make them efficient at exchanging gases w/ blood?

A
  • Thin membrane

- Close proximity to blood

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18
Q

What are the structures w/in the thoracic cavity?

A

Sternum
Vertebrae
Ribs
Diaphragm

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19
Q

What are the two types of joints in the thoracic cavity and where are they found?

A
  1. Synovial
    - (Most) sternocostal joints (b/w hyaline cartilage and sternum)
    - Interchondral joint (b/w hyaline cartilage of false ribs)
    - Costotransverse and costovertebral joints (b/w thoracic vertebrae and ribs; bi-lateral articulations)
  2. Cartilaginous
    - 1 sternocostal joint (first one - attached to clavicle)
    - Costochondral (b/w ribs and hyaline cartilage)
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20
Q

What are the muscles of respiration?

- Function?

A
  1. Diaphragm
    - Increases thoracic cavity length (lowers thoracic floor) which increases vol. –> increases size
    - Main muscle involved in inspiration
    - Skeletal muscle; contracts during inspiration
    - Phrenic nerve innervation
  2. Intercostal muscles
    - Increases tc diameter & thus vol. –> size
    - Backup/used when necessary
    - Two layers of muscle:
    a) External intercostals; inspiration; drctn of muscle fibres down and medial
    b) Internal intercostals; forced expiration; drctn of muscle fibres down and lateral
  3. Accessory muscles
    - Used during forced breathing
    - e.g. abdominal muscles
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21
Q

What is pleura?
Where are the two pleurae found?
How does one of them aid in respiration?
What is the function of pleural/serous fluid?

A
  • Serous membranes lining the thoracic cavity which secrete serous/pleural fluid into the pleural cavity
  • Visceral pleura covers the lungs
  • Parietal pleura lines the thoracic wall & mediastinum; since it is fixed there, thoracic expansion allows the lungs to expand further
  • Allows low-friction movement of the lungs, decreases surface tension and adhesion
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22
Q

Is inspiration and/or expiration passive and/or active? Why?

A
  • Inspiration is active; uses muscles to expand thoracic cavity
  • Expiration is passive; cartilage and elastin tissue recoil after inspiration
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23
Q

8 functions of the respiratory system?

A
  1. Provide O2
  2. Eliminate CO2
  3. Filter, warm and humidify inspired air
  4. Communication
  5. Sense of smell
  6. Regulates the pH of the blood
  7. Microbial defence
  8. Thermoregulation
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24
Q

What is Dalton’s law (partial pressure)?

What is total pressure for atmospheric air?

A
Partial pressure (gas) = Fraction of individual gas x total gas pressure
~760mmHg (= barometric pressure)
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25
Q

What is needed for air flow into/out of the lungs?

A

Pressure gradient (caused by change in vol.); air moves from high to low

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26
Q

What is the intrapleural space?

Function?

A
  • Lung has tendency to recoil inwards, chest wall tends to expand outwards –> gap formed
  • Helps lungs stay larger/expanded
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27
Q

What pressure is what prevents the lungs from collapsing?

A

Transpulmonary pressure

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28
Q

Function of nasal sinuses?

A
  1. Sound resonance
  2. Lighten skull
  3. Warm air
  4. Drain mucus
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29
Q

How is air warmed in the nasal cavity?

A

Large venous beds under nasal epithelium

venodilate when cold, bc blood is warm

30
Q

What happens to the structure of bronchi as they decrease in diameter? (i.e. move down the bronchial tree)

A
  • Decrease in amount of cartilage
  • Increase in amount of smooth muscle (until alveoli)
  • Decrease in cilia
  • Walls become thinner
31
Q

What is the work of breathing?

A
  1. Expanding chest/lungs
    - need to overcome stiffness/elasticity of lung/chest wall and the effects of surface tension
  2. Move air
    - airways resistance (mainly) in the upper airway; bronchoconstriction/bronchodilation
32
Q

How does a pulmonary function test (spirometry) measure the vol. and speed of air inhaled/exhaled?

A
  • Divides air in lungs into 4 volumes:
    1. Tidal vol. (TV): vol. of air moved in/out during normal breathing
    2. Inspiratory reserve vol. (IRV): extra vol. that can be inspired w/ max. inhalation
    3. Expiratory reserve vol. (ERV): extra vol. that can be exhaled w/ max. effort
    4. Residual vol. (RV): vol. remaining in lungs after max. exhalation.
33
Q

What are the lung capacities?

A
  1. Vital capacity (approx. 5L)
    - Total volume of air that can be shifted into/out of the lungs (max. breath in to max. breath out)
  2. Total lung capacity (approx. 6L)
    - Total vol. in lungs when full (VC + RV)
  3. Inspiratory capacity
    - Total vol. of air that can be held in the lungs (TV + IRL)
  4. Functional residual capacity (approx. 2.5L)
    - Vol. at end of normal breath out
  5. Residual vol. (RV)
    - vol. remaining in lungs after max. exhalation.
34
Q

What 3 factors can be used to predict someone’s forced vital capacity (FVC)?

A
  • Age
  • Height
  • Gender
35
Q

What factors indicate restrictive lung disease and chronic obstructive lung disease? What is an example of both?

A
  1. Restrictive
    - decreased lung vol/capacity (reduced lung compliance)
    - e.g. fibrosis
  2. Obstructive
    - increased resistance to airflow
    - e.g. asthma
36
Q

What is pulmonary ventilation and how do you calculate it?

A
How much air flows through the mouth:
V = f x TV
total ventilation (ml/min) = frequency (breaths/min) x tidal vol. (ml/breath)
37
Q

What is dead space? Approximate quantity per breath?

A

Inhaled air that never gets to the alveoli and thus cannot gas exchange; approx. 150mL per breath

38
Q

What is alveolar ventilation and how do you calculate it?

A

The flow of fresh gases into and out of the alveoli (accounts for dead space)
V = f x (TV - V(dead space))
ventilation (ml/min) = frequency (breaths/min) x (tidal vol. - dead space vol.) (ml/breath)

39
Q

What is hyperventilation and hypoventilation with regards to alveolar ventilation?

A
Hyperventilation = extra alveolar ventilation
Hypoventilation = low alveolar ventilation
40
Q

What factors/variables contribute to diffusion according to Fick’s Law?

A
Flux
Surface area
Thickness 
Diffusion constant
Pressure difference
41
Q

What causes emphysema? Pulmonary fibrosis?

A
  • Emphysema = reduced SA of alveolar membrane (and thus reduced partial pressure of O2 in blood)
  • Pulmonary fibrosis = increased thickness of alveolar membranes (and thus reduced partial pressure of O2 in blood)
42
Q

What does alveolar partial pressure of O2 depend on?

A
  1. Partial pressure of oxygen in inspired air
  2. Alveolar ventilation
  3. Oxygen consumption (VO2)
43
Q

What does alveolar partial pressure of CO2 depend on?

A
  1. Partial pressure of CO2 in inspired air
  2. Alveolar ventilation
  3. CO2 production (VCO2)
44
Q

In what two forms is oxygen carried in blood?

A
  1. Dissolved (very ineffective)

2. Combined with Hb (approx. 97% saturation for arterial blood and 75% in venous blood)

45
Q

What is the partial pressure of oxygen and its saturation in:
1. Arterial blood
2. Venous blood
Thus, what does binding of O2 depend on?

A
  1. 100mmHg & approx. 97%
  2. 40mmHg & approx. 75%

Thus, binding depends on the partial pressure of O2

46
Q

What does the sigmoidal shape of the oxygen-Hb curve say about O2 saturation?

A
  1. Upper flat part of the curve: moderate changes in PO2 around the normal value (100mmHg) have only SMALL effects on the % saturation
  2. Steep part of the curve at lower PO2: small changes in PO2 results in LARGE changes in % saturation; helps w/ loading and unloading

Thus, affinity increases from left to right

47
Q

What is O2 carrying capacity?

How much O2 can combine with 1 gram of Hb?

A
  • The max. amount of O2 that can be combined with Hb;
    i. e. how much Hb x how much O2 per gram of Hb
  • 1.34mL
48
Q

How do you calculate O2 content?

A

(O2 capacity x saturation) + dissolved

49
Q

Why is there an O2 difference b/w arteries and veins?

A

O2 is extracted by tissues

50
Q

In what 3 forms is CO2 transported? (Incl. relative percentages)

A
  1. Dissolved in plasma (10%)
  2. As bicarbonate (70%)
  3. Combined w/ proteins as carbamino compounds (20%)
51
Q

What is the Bohr effect? What causes a right shift?

A

~ O2-Hb dissociation curve varies w/ conditions to improve O2 uptake/delivery
~ Increased: PCO2, H+, temp –> high CO2 = unloads O2

52
Q

What is the Haldane effect?

A
  • Metabolising tissue removes more O2 from blood, which means blood can store more CO2
  • I.e. unload O2 = load more CO2
53
Q
Control of breathing:
- Central control
location/structure
function
- Senors
location
function
- Effectors
Location/structure
function
A
  1. Central control: brainstem
    - Sets rhythm of breathing
    - Coordinates sensors and effectors to maintain respiratory homeostasis
  2. Sensors: central and peripheral
    - Gather chemical/physical info from central/peripheral receptors
  3. Effectors: respiratory muscles
    - Adjust ventilation
54
Q

With regards to brainstem respiratory centres, which group is inspiration and which is mainly expiration?

A

Dorsal respiratory group = inspiration

Ventral respiratory group = expiration

55
Q

What part of the brain can override/modify the brainstem with regards to control of breathing?

A

Motor cortex (driven by choice/emotion)

56
Q
Central chemoreceptors vs. Peripheral chemoreceptors
Central:
- Function?
- Sensitive to?
- Slow or fast response? Stimulus?
Peripheral:
- Slow or fast response? 
- Sensitive to/stimulus?
A

Central:
- Most important for control of breathing
- Sensitive to PCO2
- (slow) response to pH change in ECF/CSF (due to release of H+ ions when bicarbonate dissociates)
Peripheral:
- (rapid) response to decreased arterial PO2

57
Q

Ventilatory response to CO2:

  • Main stimulus?
  • Main receptor?
  • Limits what action?
  • Factors which decrease it
A
  1. PaCO2 (tightly controlled +/- 3mmHg)
  2. Central chemoreceptors
  3. Limits breath-holding
  4. Sleep, increased age, genetic factors, training, and drugs
58
Q

Ventilatory response to hypoxia (low PO2)

  • Chemoreceptors involved?
  • Conditions for stimulation?
  • What increases response?
  • When does it become important?
A
  1. Peripheral chemoreceptors
  2. Need PO2 < 60mmHg
  3. Increased response if hypercapnic (extra CO2)
  4. Important at high altitude and in long-term hypoxemia (caused by chronic lung disease)
59
Q

Non-chemical control of breathing

  • Location of receptors
  • Connected to what via which nerve?
  • 2 types of lung receptors
A
  1. Located in the airways and lungs
  2. Connected to respiratory centres via the vagus nerve
  3. Lung receptors: stretch (lung distention) and irritants (smoke, dust, cold air)
60
Q

Function of the mucus produced by respiratory mucosa

A

Help to clean and moisten the air

61
Q

How is mucus removed from the respiratory tract?

A

Mucociliary escalator; cilia push the mucus up to the pharynx so that it is swallowed and digested

62
Q

What does the respiratory mucosa sit on top of? Purpose?

A

A vascular plexus, which allows air to be warmed

63
Q

What structures make up the URT?

A
  • Nose and nasal cavity
  • pharynx
  • larynx
64
Q

What are the regions of the pharynx?

A

Nasopharynx
Oropharynx
Laryngopharynx

65
Q

Where does the laryngopharynx extend down to?

A

Below the epiglottis, where the respiratory and digestive tracts diverge

66
Q

What does the larynx contain? Purpose?

A
  • Cartilage, to keep the airway open

- Vocal cords, produce sound

67
Q

What is below the pharynx?

A

Trachea

68
Q

Which connection allows the nasal cavity to open into the nasopharynx?

A

Internal nares

69
Q

Where are the conchae/turbinates? Function?

A

In the nasal cavity;

swirls incoming air to clean, warm and moisten it

70
Q

What ratio determines how fast someone’s air flow is?

A

FEV1 / FVC