1
Q
Define respiration.
A
Delivery of oxygen to tissues and removal of carbon dioxide from tissues.
2
Q
What are the two types of respiration?
A
External respiration and internal respiration.
3
Q
Define external respiration.
A
Ventilation and exchange of gases between lungs and blood.
4
Q
Define internal respiration.
A
Exchange of gases between blood and tissues.
5
Q
What system links external and internal respiration?
A
The circulatory (cardiovascular) system.
6
Q
What is pulmonary ventilation?
A
Movement of air into and out of the lungs.
7
Q
What two phases make up pulmonary ventilation?
A
Inspiration and expiration.
8
Q
What is pulmonary diffusion?
A
Exchange of O2 and CO2 between lungs and blood.
9
Q
Where does gas exchange occur in the lungs?
A
In the alveoli.
10
Q
List the airflow pathway to the lungs.
A
Nasal cavity/mouth → trachea → primary bronchus → secondary bronchus → tertiary bronchus → bronchioles → alveoli.
11
Q
What is the transport zone?
A
Airways where air moves but gas exchange does not occur.
12
Q
What is anatomical dead space?
A
Air remaining in conducting airways where gas exchange does not occur.
13
Q
Why is dead space important?
A
Expired air mixes with fresh atmospheric air.
14
Q
What structures make up the bronchial tree?
A
Primary, secondary, and tertiary bronchi plus bronchioles.
15
Q
What are alveoli?
A
Tiny air sacs where gas exchange occurs.
16
Q
What surrounds the lungs?
A
Pleural sacs.
17
Q
Function of pleural fluid.
A
Reduces friction during breathing.
18
Q
What are the two pleural layers?
A
Parietal pleura and visceral pleura.
19
Q
Which pleura lines the thoracic wall?
A
Parietal pleura.
20
Q
Which pleura covers the lung surface?
A
Visceral pleura.
21
Q
State Boyle’s Law.
A
Gas pressure is inversely proportional to gas volume.
22
Q
How does Boyle’s Law affect breathing?
A
Changing thoracic volume changes lung pressure and moves air.
23
Q
Is inspiration active or passive at rest?
A
Active.
24
Q
Primary muscle for inspiration.
A
Diaphragm.
25
What do external intercostals do?
Lift ribs outward and upward.
26
What happens to thoracic volume during inspiration?
It increases.
27
What happens to intrapulmonary pressure during inspiration?
It decreases.
28
Result of lower lung pressure during inspiration.
Air flows into the lungs.
29
Is expiration active or passive at rest?
Passive.
30
Why is expiration passive at rest?
Elastic recoil of lungs and relaxation of inspiratory muscles.
31
What happens to thoracic volume during expiration?
It decreases.
32
What happens to lung pressure during expiration?
It increases.
33
Result of increased lung pressure during expiration.
Air moves out of lungs.
34
Where are respiratory control centers located?
Medulla oblongata and pons.
35
Function of inspiratory center.
Controls basic breathing rhythm.
36
When is the expiratory center active?
During forceful breathing or exercise.
37
What muscles assist inspiration during exercise?
Scalenes and sternocleidomastoid.
38
What muscles assist forced expiration?
Internal intercostals and abdominal muscles.
39
Role of abdominal muscles in expiration.
Increase intra‑abdominal pressure pushing diaphragm upward.
40
External intercostals contribute roughly what percent of inspired air?
About 25%.
41
Internal intercostals primarily assist with what?
Expiration.
42
What is the respiratory pump?
Breathing movements that help venous blood return to the heart.
43
How does inhalation affect venous return?
Veins expand and fill with blood.
44
How does exhalation affect venous pressure?
Increases intrathoracic pressure aiding venous return.
45
What is spirometry?
A test measuring lung volumes and airflow.
46
Instrument used for spirometry.
Spirometer.
47
Spirometry helps diagnose what diseases?
Asthma, COPD, emphysema.
48
Define tidal volume (VT).
Air moved per breath during normal breathing.
49
Define vital capacity (VC).
Maximum air exhaled after maximal inhalation.
50
Define residual volume (RV).
Air remaining after maximal expiration.
51
Define inspiratory reserve volume.
Extra air inhaled beyond normal breath.
52
Define expiratory reserve volume.
Extra air exhaled beyond normal breath.
53
Define functional residual capacity.
Air remaining after normal expiration.
54
Define total lung capacity.
Vital capacity plus residual volume.
55
Equation for minute ventilation.
VE = VT × f.
56
What is breathing frequency (f)?
Number of breaths per minute.
57
Define alveolar ventilation.
Air reaching respiratory zone for gas exchange.
58
Define dead space ventilation.
Air remaining in conducting airways.
59
Why is deep breathing more efficient than shallow breathing?
More fresh air reaches alveoli.
60
Typical tidal volume example used in class.
500 ml per breath.
61
Fresh air reaching alveoli from 500 ml breath.
About 350 ml.
62
What is the respiratory membrane composed of?
Alveolar wall, capillary wall, and basement membranes.
63
Thickness of respiratory membrane.
About 0.5–4 μm.
64
Standard atmospheric pressure at sea level.
760 mmHg.
65
Main gases in atmospheric air.
Nitrogen, oxygen, carbon dioxide.
66
Percent oxygen in air.
~20.9%.
67
Percent nitrogen in air.
~79%.
68
Percent carbon dioxide in air.
~0.03%.
69
State Dalton’s Law.
Total gas pressure equals sum of partial pressures.
70
Define partial pressure.
Pressure exerted by one gas in a mixture.
71
Partial pressure of oxygen at sea level.
About 159 mmHg.
72
State Henry’s Law.
Gas dissolved in liquid is proportional to its partial pressure.
73
State Fick’s Law.
Diffusion depends on pressure gradient, surface area, and membrane thickness.
74
Factors increasing diffusion rate.
Large surface area and high pressure gradient.
75
Factor decreasing diffusion rate.
Greater membrane thickness.
76
CO2 diffusion compared to O2.
CO2 diffuses about 20 times faster.
77
Alveolar PO2 value.
About 105 mmHg.
78
Alveolar PCO2 value.
About 40 mmHg.
79
Pulmonary capillary PO2 before gas exchange.
About 40 mmHg.
80
Direction of oxygen diffusion.
Alveoli → pulmonary capillaries.
81
Direction of CO2 diffusion.
Capillaries → alveoli.
82
PO2 in pulmonary vein.
About 100 mmHg.
83
What causes slightly lower pulmonary vein PO2?
Mixing with shunted blood.
84
Systemic venous PO2.
About 40 mmHg.
85
Systemic venous PCO2.
About 46 mmHg.
86
What increases O2 diffusion during exercise?
Increased lung perfusion.
87
How much can diffusion capacity increase during exercise?
Up to about 3 times.
88
Percent of O2 transported bound to hemoglobin.
About 98%.
89
Percent of O2 dissolved in plasma.
About 2%.
90
How many O2 molecules can hemoglobin bind?
Four.
91
Define oxyhemoglobin.
Hemoglobin with oxygen bound.
92
Define deoxyhemoglobin.
Hemoglobin without oxygen.
93
What is the oxygen‑hemoglobin dissociation curve?
Relationship between PO2 and hemoglobin saturation.
94
Upper flat part of O2 curve significance.
Hemoglobin remains saturated even if PO2 drops slightly.
95
Steep part of O2 curve significance.
Small PO2 changes cause large oxygen release to tissues.
96
Define Bohr effect.
Lower pH shifts curve right, promoting oxygen unloading.
97
What does increased temperature do to curve?
Shifts it right.
98
Effect of increased CO2 on curve.
Shifts it right.
99
Effect of higher pH on curve.
Shifts it left.
100
What is 2,3‑DPG?
A glycolysis byproduct in RBCs affecting hemoglobin affinity.
101
Effect of 2,3‑DPG on O2 curve.
Shifts curve right.
102
Define a‑vO2 difference.
Difference between arterial and venous oxygen content.
103
a‑vO2 difference at rest.
About 4–5 ml O2 per dl.
104
a‑vO2 difference during exercise.
About 15–16 ml O2 per dl.
105
What does larger a‑vO2 difference indicate?
Greater oxygen use by tissues.
106
State Fick equation.
VO2 = Q × (a‑vO2 diff).
107
What is VO2?
Rate of oxygen consumption.
108
What does Q represent?
Cardiac output.
109
What protein transports oxygen in muscle?
Myoglobin.
110
How many O2 molecules can myoglobin bind?
One.
111
Myoglobin affinity for oxygen compared to hemoglobin.
Much higher.
112
Why is myoglobin important?
Helps deliver oxygen to mitochondria.
113
What regulates breathing at rest?
Chemoreceptors and mechanoreceptors.
114
Central chemoreceptors respond primarily to what?
CO2 levels via H+ concentration.
115
Peripheral chemoreceptors detect what?
PO2, PCO2, and pH changes.
116
Strongest stimulus for ventilation.
Increase in CO2.
117
Define hypoventilation.
Insufficient ventilation causing CO2 buildup.
118
Result of hypoventilation.
Respiratory acidosis.
119
Define hyperventilation.
Excessive breathing causing CO2 loss.
120
Result of hyperventilation.
Respiratory alkalosis.
121
What is the Hering‑Breuer reflex?
Stretch receptors stop excessive lung inflation.
122
Why is hyperventilation dangerous before diving?
Reduces CO2 drive to breathe.
123
What is shallow water blackout?
Loss of consciousness from low oxygen during breath‑hold diving.
124
Why is carbon monoxide dangerous?
It binds hemoglobin ~230× stronger than oxygen.
125
CO effect on oxygen transport.
Prevents oxygen from binding hemoglobin.
KRS 354
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