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PL2022: Introductory Physiology II > Respiratory System > Flashcards

Respiratory System Flashcards

(79 cards)

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1
Q

Where does gas exchange occur?

A

Alveoli

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2
Q

How does INSPIRATION occur?

A

By reducing the air pressure in lungs to sub-atmospheric pressure = increase in lung volume

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3
Q

How does EXPIRATION occur?

A

By increasing air pressure in lungs above atmospheric pressure = decrease in lung volume

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4
Q

What is Boyle’s Law?

A

Pressure of a quantity of gas is inversely proportional to its volume

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5
Q

Where is the diaphragm muscle located?

A

At the base of the thoracic cavity

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6
Q

What are the TWO pleural membranes?

A
  • Parietal pleura (inner wall of thoracic cavity)
  • Visceral pleura (outer surface of lungs)
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7
Q

What fluid adheres pleural membranes to each other?

A

Pleural fluid in pleural cavity

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8
Q

What are the muscles contracting during NORMAL inspiration?

A
  • Diaphragm
  • External intercostal muscles
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9
Q

What muscles are involved during FORCED inspiration?

A
  • Scalenes (neck muscles)
  • Pectoralis minor (chest muscles)
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10
Q

What is the drop in intrapulmonary pressure during normal and forced INSPIRATION?

A

Normal: -3mmHg
Forced: -20mmHg

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11
Q

What is the INCREASE in intrapulmonary pressure during normal and forced EXPIRATION?

A

Normal: +3mmHg
Forced: +30mmHg

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12
Q

What are the muscles activated during FORCED expiration?

A
  • Internal intercostal muscles
  • Abdominal muscles
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13
Q

What walls are the lungs attached to?

A

Inner wall of thoracic cavity

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14
Q

What causes intrapleural pressure?

A

Both pleural membranes being pulled in opposite directions

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15
Q

Is intra-alveolar pressure lower than intrapleural pressure?

A

No
Intrapleural pressure is ALWAYS lower than intra-alveolar pressure

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16
Q

What is atmospheric pressure?

A

760mmHg

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17
Q

What is intrapleural pressure?

A

756mmHg

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18
Q

What is Pneumothorax?

A

Collapsed lungs due to damage of pleural membranes caused by broken rib or stab wound

Causes intra-alveolar pressure and intrapleural pressure to equalise

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19
Q

What is Pneumothorax?

A

Collapsed lungs due to damage of pleural membranes caused by broken rib or stab wound

Causes intra-alveolar pressure and intrapleural pressure to equalise

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20
Q

What is alveolar surface tension?

A

Interaction of thin fluid produced by spherical alveoli and air in alveoli

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21
Q

What does surface tension do in the alveoli?

A

Pulls water molecules together exerting inward force on alveoli which opposes expansion of lung tissues during inspiration

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22
Q

What is Surfactant?

A

It breaks surface tension by breaking H-bonds between molecules

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23
Q

How is surfactant produced?

A

Produced by Type II alveolar cells

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24
Q

What is the primary determinant of resistance to air flow?

A

Radius of the airways

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25
Name the TWO neurotransmitters that innervate smooth muscles in bronchioles
1. Noradrenaline - released by sympathetic nerves triggers bronchodilation 2. Acetylcholine - released by parasympathetic nerves triggers bronchoconstriction
26
How is asthma treated?
With anti-inflammatory agents and β-adrenergic receptor agonists
27
What do β-adrenergic receptor agonists do?
Trigger relaxation resulting in bronchodilation
28
What is the function of the pulmonary function test?
Measure the quantity of air inhaled
29
What apparatus is used to measure the volume of air moving for each breath?
Spirometer
30
What is Tidal Volume?
Volume of air expired or inspired during regular breathing (usually 500ml)
31
What is the Residual value and can it be measure using spirometry?
Volume of air remaining in lungs after maximal expiration (average ~1200ml) and it can't be measured using spirometry
32
What is Vital Capacity?
Tidal Volume + ERV + IRV (average ~4600ml)
33
What is Total Lung Capacity?
Vital Capacity + Residual Volume (average ~5800ml)
34
What is one second forced expiratory volume (FEV1)?
Measures % of exhaled vital capacity in 1 sec ## Footnote Used to diagnose obstructive lung disorders
35
What is one second forced expiratory volume (FEV1)?
Measures % of exhaled vital capacity in 1 sec ## Footnote Used to diagnose obstructive lung disorders
36
What does Dalton's Law state?
Total pressure of the mixture is the sum of individual gases' pressures
37
What is Partial Pressure?
Individual pressure of each gas (atmospheric pressure x % of gas in atmosphere)
38
What is the partial pressure of oxygen?
160mmHg
39
What is the partial pressure of CO2?
0.25mmHg
40
What is Henry's Law and its THREE variables?
Gas ability to dissolve in blood: 1. Pressure gradient from air to blood 2. Solubility of gas in water 3. Temperature of the blood (constant)
41
What is normal alveolar PO2?
100mmHg
42
What is the PO2 of the systemic venous blood arriving in the pulmonary arterial capillaries?
40mmHg
43
What is the PO2 in the cells?
40mmHg
44
What is the PCO2 in the cells?
46mmHg
45
What is the PCO2 of arterial blood?
40mmHg
46
What is the alveolar PCO2?
40mmHg
47
What is Hypoxaemia?
**Abnormally low arterial PO2** resulting in hypoxia (O2 deficiency in tissues)
48
How is Hypoxia recognised?
Cyanosis, bluish colouration of skin/mucous membranes
49
What happens to PO2 at high altitudes?
* Atmospheric pressure falls * PO2 entering the lungs decreases * Alveolar PO2 decreases
50
What is Emphysema?
Restrictive pulmonary disorders causing alveoli destruction
51
What is Pulmonary Oedema?
Increase fluid in the tissue of alveoli
52
What are the TWO ways oxygen is transported into the blood?
1. Dissolved in plasma 2. Bound to haemoglobin (98% of O2)
53
What are the TWO factors that the amount of O2 bound to haemoglobin is dependent on?
1. PO2 of the plasma 2. Total amount of haemoglobin in the blood
54
How many subunits does a haemoglobin molecule have?
4
55
What is Oxyhaemoglobin?
Irons reduced form (Fe2+) bound to O2
56
Where do loading reactions occur?
Association of PO2 and Fe2+ occurs in pulmonary capillaries
57
What is the primary determinant of O2 binding to plasma?
PO2 in plasma
58
What type of curve is the oxyhaemoglobin curve?
Sigmoidal (S-shaped)
59
What happens to PO2 of tissue fluid/plasma around cells if PO2 falls to 20mmHg?
Extra 40% of O2 is released by haemoglobin
60
How much O2 is still bound to haemoglobin under normal resting conditions?
75%
61
How does a drop in blood pH affect the affinity between haemoglobin and O2?
A drop **decreases the affinity** of haemoglobin for O2 (release of more O2 into the cells)
62
How does an increase in temperature and in 2,3-DPG release affect affinity between haemoglobin and O2?
It decreases affinity
63
How is CO2 transported into the blood?
Dissolved in plasma, and bound to haemoglobin or converted to bicarbonate in RBCs
64
What is the enzyme in red blood cells that converts CO2 and H2O to carbonic acid?
Carbonic Anhydrase (CA)
65
What is Chloride Shift?
Transportation of bicarbonate out of the RBC in exchange of Cl- ion
66
What is formed by the binding of CO2 to haemoglobin?
Carbaminohaemoglobin
67
What is the muscle type of respiratory muscles?
Skeletal
68
What initiates muscle contraction of respiratory muscles?
Somatic motor neurons (phrenic nerves)
69
What sets the breathing rate?
A region of the medulla oblongata known as the rhythmicity centre
70
What is the property and function of chemoreceptors?
* They **detect changes in PO2 and PCO2** * They **alter the ventilation rate** to keep this value in the normal range
71
What do chemoreceptors do if PCO2 increases?
They cause an increase in the rate and depth of breathing
72
What is breathing regulation primarily controlled by?
Chemoreceptors sensitive to PCO2
72
What is breathing regulation primarily controlled by?
Chemoreceptors sensitive to PCO2
73
At what mmHg are arterial PCO2 and PO2 maintained?
PCO2 - 40mmHg PO2 - 100mmHg
74
Where are CENTRAL chemoreceptors located?
On the medulla oblongata, close to neurons of the rhythmicity centre
75
What are the effects of an increase in blood PCO2?
Increase in CO2 diffusion across the blood-brain barrier making pH of CSF fall
76
Where are the PERIPHERAL chemoreceptors located?
In the carotid and aortic bodies (same regions of vasculature as baraoreceptors)
77
Where are the PERIPHERAL chemoreceptors located?
In the carotid and aortic bodies (same regions of vasculature as baraoreceptors)
78
How can a dramatic reduction in PO2 occur?
Only occurs at very high altitudes or in individuals with pulmonary disorders

PL2022: Introductory Physiology II (6 decks)

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