Respiratory Physiology Flashcards
1
Q
What are the 4 functions of the respiratory system?
A
- Oxygenation of blood
- Removal of CO2
- Control of acid-base balance
- Production of vocalization
2
Q
What is the only organ to receive the full cardiac output?
A
The lungs
3
Q
At what 3 levels does respiration occur?
A
- Gas exchange in lungs
- Circulation of gases through the blood stream
- Gas transfer at cellular level
4
Q
What volume of air is exchanged at the lungs during each inspiration/ expiration?
A
- 350 mL
5
Q
What is respiration?
A
- Delivery of O2 to cells
- Removal of CO2
6
Q
What is pulmonary ventilation?
A
- Inflow/ outflow of air in the lungs
7
Q
What is external pulmonary ventilation?
A
- Exchange of gases between lungs and blood
8
Q
What is internal tissue respiration?
A
Exchange of gases between blood and tissues.
9
Q
What 3 structures make up the upper respiratory system?
A
- Nose
- Mouth
- Pharynx
10
Q
What are the 3 functions of the nose and mouth in respiration?
A
- Filtering
- Humidification
- Warming and cooling
11
Q
What are the 2 functions of the pharynx?
A
- Vocal cords help produce sound
- Conduit to larynx and trachea
12
Q
What 4 structures make up the lower respiratory system?
A
- Larynx
- Trachea
- Bronchi
- Lobes
13
Q
What 2 major structures around found in the larynx?
A
- Epiglottis
- Circoid (complete cartilage ring that provides attachments for structures involved in speech production)
14
Q
What are the 2 types of cells found in the alveolar walls? What are their functions?
A
Type I: Squamous cells functioning in gas exchange
Type II: Surfactant producing cells. Lower surface tension: keep alveoli open, and help them expand more easily.
15
Q
What are the 3 primary muscles of inspiration?
A
- Diaphragm
- External intercostals
- Interchondral intercostals
16
Q
What are the 5 accessory muscles of inspiration? What is their function?
A
- Increase diameter of chest cavity
- Scalenes
- Sternocleidomastoid
- Serratus anterior
- Pectoralis major
- Pectoralis minor
17
Q
What are the 2 muscle groups of expiration?
A
- Abdominals
- Internal intercostals
18
Q
What muscle group creates the bucket handle motion of the rib cage?
A
- External intercostals
19
Q
The diaphragm contains many which cell organelle?
A
Mitochondria.
20
Q
What 4 situations may cause the diaphragm to become fatigued?
A
- Disease states
- Exercise
- Nutrition
- Ventilators
21
Q
What spinal chord segments innervate the diaphragm?
A
- C3
- C4
- C5
22
Q
What is paradoxal movement of the diaphragm?
A
- Diaphragm moves up during inspiration, sucking the abdomen in
23
Q
What 2 cavities does the diaphragm separate?
A
- Abdominal cavity
- Thoracic cavity
24
Q
When the diaphragm has an optimal length-tension ratio, what position causes the maximum passive tension in the muscle?
A
At functional residual capacity
25
What closes during coughing to help increase the pressure inside of the thorax?
The glottis.
26
What is paradoxical exhalation? What causes it in infants? In adults?
- Chest collapses during exhalation
- Infants ribs are not ossified
- Adults have incompetent intercostals
27
What is intrapulmonary pressure?
- Pressure in the alveoli
28
What is intrapleural pressure?
- Pressure in pleural cavity between parietal and visceral pleura.
29
What is the difference between the intrapulmonary pressure and the intrapleural pressure?
About 4 less mmHg.
30
What is transpulmonary pressure?
The difference between the intrapulmonary and intrapleural pressures.
31
What pathologies can cause the bronchi to constrict?
- Asthma, or other pathologies that cause the bronci to constrict.
32
What is lung compliance measured by?
- Pressure-volume curve.
33
Does increased compliance increase or decrease lung volume?
Increase.
34
Describe decreased compliance using pressure and volume.
Larger pressure required to create smaller volume
35
What are the 2 neurological mechanisms of control of respiration? What are their roles?
Medulla: Controls rate and depth of respiration
Pons: Moderates rhythm of inspiraton/ expiration
36
Where are the chemoreceptors located that are sensitive to changes in CO2 and O2?
- Aorta
| - Carotid arteries
37
What is hypoxic drive?
Decreased oxygen drives change in breathing.
38
What blood gas are chemoreceptors especially sensitive to?
CO2
39
What is tidal volume?
The volume of gas inspired or expired during each respiratory cycle.
40
What is tidal volume a measure of functionally?
The depth of breathing
41
What is the expiratory reserve volume?
- Maximum amount of air expired after a normal expiration
42
What is residual volume?
The gas remaining in the lungs after a max expiration.
43
What is the inspiratory reserve volume?
- Maximum amount of gas inspired from peak inspiratory tidal volume.
44
What is total lung capacity?
- Amount of air in respiratory system after max inspiration
45
What is vital capacity?
Maximum amount of air expired after a maximum inspiration.
46
What is inspiratory capacity?
Maximum inspired volume of air from resting expiration level.
47
What is functional residual capacity?
Volume of gas in lungs when the respiratory system is at rest.
48
What is the path of air from the nasal passages to the alveoli (site of gas exchange)? (10 steps)
- Nasal passages
- Pharynx
- Larynx
- Trachea
- Right/left main stem bronchus
- Lobar bronchi
- Segmental bronchi
- Bronchioles
- Alveolar ducts
- Alveoli
49
What airways make up the anatomical dead space of the respiratory system?
- Pharynx
- Larynx
- Bronchiole airways
50
What is the normal volume of anatomical dead space?
150 mL.
51
What is alveolar dead space?
- Ventilated, but not gas exchange takes place
52
What can commonly cause anatomic dead space?
- Pulmonary embolus
53
What is physiological dead space?
- No gas exchange due to disease or emphysema
54
What is the name of a respiratory unit?
- Acinus
55
What is contained within an acinus?
- Respiratory bronchioles
- Alveolar ducts
- Alveolar sacs
- Alveoli
56
What real-life structure quantifies the amount of surface area provided by the alveoli in the lungs for gas exchange?
- A tennis court
57
By what process does gas exchange occur?
- Diffusion
58
What characteristics of the gases being exchanged affect the diffusion of gases at the alveoli?
- Partial pressure gradients (greater to smaller)
| - Gas solubility
59
What is the composition of dry air at sea level? (in terms of percentages)
- 21 % O2
- 0.04 % CO2
- 78.07 % Nitrogen
- 1 % other gases (argon & helium)
60
Since atomspheric pressure is 760 mmHg, what is the amount of pressure due to O2?
160 mmHG.
61
What can change the partial pressure of oxygen?
Location respective to sea level.
- High level
- Below sea level
- Underwater
- Respiratory tract
- Humidificaiton
62
What are the PO2 and PCO2 of inspired air and air in the alveolar capillaries? How does this drive gas exchange?
Inspired air:
- O2: 160 mmHg
- CO2: 0.3 mmHg
Alveolar capillaries:
- O2: 40 mmHg
- CO2: 45 mmHg
Gas diffuses across membrane from high to low until the 2 pressures are balanced.
63
What are the partial pressure of CO2 and O2 after gas exchange has occured in the lungs? What structure does the "oxygenated blood" enter?
- PO2: 104 mmHg
- PCO2: 40 mmHg
Returns to left atrium through pulmonary veins.
64
Describe the 3 step process of O2 transferring from arterial blood to energy in muscle cells.
- O2 dissociates from the arterial hemoglobin into the blood
- Diffuses across the capillary membrane into muscle cells
- Mitochondria use O2 to create ATP
65
Describe the 4 step process of the disposal of CO2 from the body.
- CO2 diffuses from muscle cells to capillaries
- Transports back to the heart through the venous system
- RV pumps the blood into the lungs
- CO2 diffuses into alveoli and is exhaled
66
What are the partial pressures of expired air?
- 120 mmHg O2
| - 27 mmHg CO2
67
How is CO2 transported in the blood?
CO2, which is more soluble than O2 dissolves into the blood, and forms H2CO3;
H2CO3 dissociates into HCO3- and H+.
68
How do the lungs regulate the acidity of the body?
Expelling CO2.
69
How do the kidneys control the acid base balance as relates to CO2?
Maintains/ excretes bicarbonate and H+.
70
How does the acidity of blood affect O2 transport?
- Less O2 binds to hemoglobin in acidic envirnoments
71
What is the V/Q ratio?
- Ventilation/ perfusion
| - Ratio of alveolar ventilation to pulmonary blood flow
72
What is the normal V/Q? What are the P02 and PCO2 at this ratio?
- 0.8 or 80%
- PO2 is 100 mmHg
- PCO2 is 40 mmHg
73
Which direction does the oxyhemoglobiin dissociation curve shift in acidosis?
To the right.
74
Which direction does the oxyhemoglobin dissociation curve shift in alkalosis?
To the left.
75
What partial pressure is the oxyhemoglobin curve not especially sensitive to?
- O2
| - Doesn't take much O2 to saturate the hemoglobin
76
What is a measure of oxygen-hemoglobin binding? What is a normal value?
SaO2 measures the percent of hemoglobin saturated by oxygen.
- Normal is 95 % or more
77
How high is the aterial blood pressure in the apices?
- Just high enough to prevent closure of the pulmonary capillaries.
78
Why is blood flow within the lung typically uneven? What position can balance the blood flow throughout the lungs?
- Uneven due to gravity
| - Supine position evens out the effects of gravity
79
Where is blood flow the lowest and highest in the lungs when standing?
- Lowest at apex (superiorly)
| - Highest at base (inferiorly)
80
If a patient's lungs are injured unilaterally, how can the patient be positioned for ideal perfusion?
- Side lie onto the good lung.
81
State the lowest, medium, and highest blood flow, and the pressure relationships in each portion of the lung.
- Alveolar pressure (PA)
- Arterial pressure (Pa)
- Venous pressure (Pv)
- Zone 1 (Superior)
- Zone 2 (Middle)
- Zone 3 (inferior)
(Standing position)
Blood flow: Zone 3 > Zone 2 > Zone1
Pressures:
Zone 1: PA > Pa > Pv
Zone 2: Pa > PA > Pv
Zone 3: Pa > Pv > PA
82
What drives blood flow in Zone 2 of the lung in standing?
- Difference between arterial and alveolar pressure.
83
What drives blood flow in Zone 3 of the lungs?
- Difference between aterial and venous pressure
| - Most capillaries are open
84
What type of pathology can cause a shunting of blood?
Heart defect.
85
How does a right to left shunt occur?
If the wall between the right and left ventricles are compromised.
86
How does a left to right shunt occur?
- Ductus arteriosus
| - Traumatic injury
87
Which type of shunting leads to hypoxemia?
- right-to-left because much of the CO is not delivered to the lungs for oxygenation.
88
Why does left-to-right shunting typically not cause hypoxemia?
- Blood gets doubly oxygenated, which while causing some extra work for the heart, is not as bad as blood not getting oxygenated at all.
89
What zone of the lung has the highest V/Q?
- Zone 1
90
What zone of the lung has the highest O2 partial pressure?
- Zone 1
91
Which zone of the lung has the highest alveolar ventilation?
- Zone 3
92
Which zone of the lung has the lowest blood flow?
- Zone 1
93
Which zone of the lung has the highest partial pressure of CO2?
- Zone 3
94
Which zone of the lung has the lowest V/Q?
- Zone 3
95
What are 3 lines of defense against inhaled organisms and particles in the respiratory system?
- Nasal mucosa
- Nasal hair/ cilia
- Type II pnemocytes
96
What cells provide the immunodefense properties of the nasal mucosa? What do they secrete?
- Goblet cells
- Broncho seromucous glands
- Produce immunoglobulin A containing mucous
97
What increases the production of mucous by the goblet and bronchial seromucous glands?
Inflammation.
98
What 4 factors can impair nasal hair/ cilia?
- Nicotine
- Inflammation
- Infection
- Anesthesia
99
Why do so many pulmonary infections occur post-op?
Nasal hair/ cilia are paralysed under anesthetic.
100
What is produced by type II pneumocytes?
Surfactant.
101
What 4 cells act as immunodefense to the lungs?
- Alveolar macrophages
- B lymphocytes
- Polymorphonuclear leukocytes
- Mast cells
102
What type of defense cell is more prevelant in smokers and individuals with asthma?
- Mast cells (release mediators)
103
Which defense cell of the lung produces gamma globulin for production of antibodies?
B lymphocytes.
104
What 5 factors impede activity of alveolar macrophages?
- Nicotine
- Air pollution
- Alcohol
- Corticosteroid therapy
- Radiation
