Midterm 1 Flashcards
Lectures 1-5 + Auscultation Basics
1
Q
thorax
A
area between the abdomen and neck
consists of the boney thoracic wall and thoracic cavity
2
Q
thoracic wall
A
consists of sternum, 12 pairs of ribs and their cartilages, and 12 thoracic vertebrae
protects the heart and lungs
3
Q
3 main regions of the thoracic cavity
A
1) right pleural cavity
2) left pleural cavity
3) mediastinum
4
Q
types of pleura
A
- visceral pleura: inner layer that covers the external lung surfaces
- parietal pleura: outer layer that covers the mediastinum, inner thoracic cavity, and diaphragm
4
Q
purpose of pleural fluid
A
- creates surface tension that holds the layers together
- reduces friction between lungs and thoracic wall
5
Q
pleural blood and nerve supply
A
visceral pleura:
nerve: no sensory innervation
blood: bronchial and pulmonary arteries
parietal pleura:
nerve: phrenic and intercostal nerves
blood: intercostal and phrenic arteries
6
Q
hilum of the lung
A
region where nerves, primary bronchi, and vessels enter/exit the lung
7
Q
root of the lung
A
collection of structures that connect the lung to the mediastinum
8
Q
lobes of the lungs
A
right lung: upper, middle, lower
left lung: upper and lower
9
Q
fissures of the lungs
A
right: horizontal and oblique
left: oblique
10
Q
vasculature of the lungs
A
- pulmonary artery brings deoxygenated blood to the lungs
- pulmonary vein brings oxygenated blood to the left ventricle of the heart
- bronchiole arteries supply lung tissues
11
Q
innervation of lungs
A
1) pulmonary plexus
2) phrenic nerve (sensory and motor) - C3,C4,C5
12
Q
parts of lower respiratory system
A
1) tracheobronchial tree (conducting airways)
2) terminal respiratory units
13
Q
tracheobronchial tree
A
- doesn’t participate in gas exchange. just brings air to respiratory units
- consists of trachea, primary bronchi, tertiary bronchi, bronchioles, terminal bronchioles
14
Q
what main bronchus has a steeper angle
A
right
15
Q
carina
A
ridge of cartilage where trachea bifurcates which has a cluster of cough receptors (also important landmark for suctioning)
16
Q
cells of the tracheobronchial tree
A
- cilia: hairlike projections on airway epithelium
- goblet cells: secrete mucous film
- club cells: secrete glycosaminglycans to protect bronchiole lining
- cartilage: helps prevent collapse
- smooth muscle: changes diameter of airways
17
Q
how are bronchioles held open?
A
radial traction
18
Q
terminal respiratory units
A
- respiratory bronchioles, alveolar ducts, alveoli sacs
- where gas exchange occurs
- 90% of total lung volume
19
Q
cells of alveolus
A
1) type 1 pneumocytes:
- 95% of surafe area
- share basement membrane with pulmonary capillaries for gas exchange
2) type 2 pneumocytes:
- in between type 1s
- cuboidal cells with microvilli
- contains surfactant to decrease surface tension
3) alveolar macrophage:
- collects and destroys inhaled particles
20
Q
methods for airway clearance
A
1) mucociliary escalator
2) cough
3) alveolar macrophages
21
Q
mucociliary escalator
A
- located in trachea, bronchi, bronchioles
- cilia beat to move particles toward mouth
- mucous film is secreted by goblet cells (gel layer traps particles and sol layer lubricates airway for cilia to beat)
22
Q
cough
A
- assists mucociliary escalator
3 phases of a cough:
1) inspiratory: negative intra-abdominal pressure
2) compressive: increased intra-abdominal pressure
3) expulsion: glottis opens
23
Q
4 properties of sputum assessment
A
1) quantity
2) colour
3) purulence
4) viscosity
24
hemoptysis
presence of blood when coughing
25
extracellular matrix of lung
- holds lung together, provides stability, provides elastic recoil
- basement membrane: underlies airways, alveolar epithelium, smooth muscle
- interstitium: spaces between cells that contains elastin and collagen
26
ventilation
bringing air in and out of the lungs. not gas exchange
26
muscles of inspiration
1) diaphragm
2) external intercostals
3) accessory muscles
26
diaphragm
- main inspiratory muscle
- has central tendon that esophagus, abdominal aorta, and inferior vena cava passes through
- innervated by phrenic nerve
- contraction increases diameter of thorax
27
external intercostals
- inspiratory muscles
- pulls ribs up and out
28
pump handle motion
- moves sternum outward (increases anterior/posterior diameter)
- ribs 2-5
29
bucket handle motion
- elevates ribs (increases transverse diameter)
- ribs 8-10
- most important for getting air into lungs
30
what ribs can contribute to both pump handle and bucket handle motions
ribs 6-7
31
chest wall abnormalities
- barrel chest
- scoliosis
- pectus carinatum (pigeon chest)
- pectus excavatum (funnel chest)
- kyphosis
32
movements of accessory muscles on the ribs
during respiratory distress
- scalenes: lifts first 2 ribs
- SCM: lifts sternum outward
- neck and back muscles: elevates pectoral girdle and expands back
33
is respiratory distress a diagnosis?
NO. it is a sign that the body is working harder to breathe
34
signs of respiratory distress
- increased resp. rate (tachypnea)
- increased HR
- intercostal indrawing
- paradoxical breathing
- accessory muscle use
- tripod position
- pursed lip breathing
- diaphoresis (sweating)
- cyanosis
35
signs of respiratory distress in children
- head bobbing (traps are not developed
- nasal flaring (sympathetic response to decrease airway resistance)
- grunting (increasing pressure in lungs)
36
zone of apposition
region where the muscle fibres of the diaphragm are apposed (in direct contact) with the inner surface of the lower ribs
this is advantageous and important for effective diaphragm function and breathing mechanics
37
how is the zone of apposition advantageous for diaphragm function and breathing mechanics?
1) creates efficient pressure gradient:
- during inhalation, diaphragm contracts increasing thoracic volume and decreasing thoracic pressure. this also increases intra-abdominal pressure which aides lower rib expansion
- essential for creating negative pressure suction to bring air into the lungs
2) aides lower rib movement which further increases thoracic volume and decreases thoracic pressure
3) helps maintain optimal diaphragm muscle length to ensure maximal
force production
4) maintains diaphragms curvature to ensure effective contraction
38
what can cause the zone of apposition to be reduced or lost?
- flattening of the diaphragm (causes decreased pressure gradient)
- decreased rib movement
- reduced muscle efficiency through length:tension relationship
clinical causes:
- hyperinflated lungs (diaphragmm not at optimal length)
- abdominal paralysis or weakness (decreases pressure gradient)
39
normal breath sounds
- vesicular
- bronchovesicular
- bronchial
40
vesicular breath sounds
- created by air moving through the bronchioles
- gentle rustling sound
- located over normal lung tissue over most of chest wall
- inspiration > expiration
41
bronchovesicular breath sounds
- created by air moving in large bronchi and trachea
- louder and higher pitch than vesicular
- located over each side of sternum or between scapulae (abnormal anywhere else)
- inspiration = expiration
42
bronchial
- darth vader
- created by vibration of air in tracheobronchial system
- blowing, hollow sound
- located just above clavicles on each side of sternum or over manubrium (abnormal anywhere else)
- expiration > inspiration
43
absent or reduced breath sounds
- caused by reduced airflow
- some sound barrier between the airway and chest wall
- obesity, pleural effusion, tumor, etc.
44
adventitious breath sounds
additional respiratory sounds superimposed over breath
- fine inspiratory crackles
- coarse crackles
- wheeze
- stridor
- pleural rub
45
fine inspiratory crackles
- most common
- discrete popping sounds caused by re-opening of closed airspaces (sounds like hair between fingers)
- heard at end of inspiration at lung bases
- can be reduced by deep breathing
46
coarse crackles
- bubbling sound
- caused by re-opening of closed airways
- usually due to secretions in lungs
- louder, lower pitch, longer lasting than FIC
- heard in first few inpsirations before a cough or deep breath
47
wheeze
- whistling sound
- produced by air passing through a narrowed bronchus/bronchiole by mucous, swelling, muscle spasm, tumor
- usually on expiration
- if caused by secretions, it can be cleared by a cough
48
stridor
- loud, high pitched sound
- higher pitch = more narrow airway
- occurs when there is a obstruction of the upper airway (inhaled lego)
- heard in croup, foreign body aspiration, tumor of upper airway
- louder in neck and on inspiration
- can be heard without stethoscope
49
pleural rub
- walking on snow
- grating sound from inflammed pleura rubbing together
- usually louder because its closer to the chest wall
- not cleared by cough
- coughing and breathing will be painful
50
where does ventilation control come from?
respiratory control centre in medulla oblongata and pons of hindbrain
51
how is ventilation controlled?
- chemoreceptors in the lungs monitor PCO2, PO2, and pH in blood and mechanoreceptors detect the stretch of lung tissue and irritants.
- this info is sent to the respiratory control centre
- respiratory control centre works by intrinsic drive and processes the info from receptors to determine what the body needs
- neurons send impulses to the primary respiratory muscles via the phrenic and intercostal nerves to stimulate contraction based on rate and depth of breathing needed
52
hyperventilation
- NOT a sign of respiratory distress
- abnormal ventilation pattern
- eliminates more CO2 than the body can produce which causes hypocapnia (decreased blood CO2) making the body more alkalitic
53
symptoms of decreased blood CO2
- feeling dizzy/faint
- chest pain
- shortness of breath
- numbness of hands or feet
54
types of chemoreceptors
1) central chemoreceptors in medulla
2) peripheral chemoreceptors in carotid artery and aortic arch
55
central chemoreceptors in medulla
- unaffected by O2 in normal conditions
- monitors PCO2 and pH in cerebral spinal fluid
- when PCO2 increases, CO2 diffuses into CSF and reacts with H2O to make H2CO3
- H+ dissociates to form HCO3- and H+
- increased H+ increases acidity (lower pH) which activates respiratory control centre which send impulse to diaphragm and external intercostals to increase ventilation
56
peripheral chemoreceptors in carotid artery and aortic arch
- respond to changes in O2 when PaO2 < 60mmHg to increase ventilation (when things get really bad)
- can also respond to PaCO2 but not as much
57
normal respiratory rate, tachypnea, and bradypnea
normal: 12-20bpm
tachypnea: >20bpm
bradypnea: <12bpm
58
tidal volume (VT)
volume of air inhaled/exhaled during normal breath (~300-500ml)
59
minute ventilation
total volume of air inhaled/exhaled in 1 minute
minute ventilation = VT x RR
60
inspiratory reserve volume (IRV)
additional volume that can be inhaled beyond normal tidal inspiration
61
expiratory reserve volume (ERV)
additional volume that can be exhaled after normal tidal exhalation
62
residual volume (RV)
air that remains in lungs after a forceful expiration (so lungs don't collapse)
63
inspiratory capacity (IC)
IC = TV + IRV
64
vital capacity (VC)
VC = TV + IRV + ERV
total volume exhaled after a maximal inhalation)
65
total lung capacity (TLC)
TLC = TV + IRV + ERV +RV
sum of all volumes
66
functional residual capacity (FRC)
FRC = ERV + RV
volume of air remaining in lungs after normal passive exhale
keeps small airways open and keeps a volume of lungs at the end of expiration to aid gas exchange
67
be able to label graph!!!!!
A - inspiratory reserve volume
B - tidal volume
C - expiratory reserve volume
D - residual volume
E - inspiratory capacity
F - functional residual capacity
G - vital capacity
H - total lung capacity
68
mechanics of ventilation
1) muscles contract
2) volume changes
3) pressure changes
69
3 pressures that ventilation depends on
1) P atmosphere
2) P alveolar: always equalizes to Patm after inhalation/exhalation
3) P intra-pleural: always negative relative to atmosphere under normal conditions
70
why is Pip always negative?
- the negative pressure is created by the elastic recoil of the lungs pulling inward and the elastic recoil of the chest wall pulling outward
- causes suctioning which keeps the lungs from collapsing because the outward pull is slightly > than the inward pull
- this negative pressure holds the lungs and thoracic wall in close approximation which maintains lung inflation between breaths (maintain FRC)
71
pressure changes during inspiration
- diaphragm and external intercostals contract which increases the volume of the thorax which increases lung volume. this decreases Palv
- air flows from atmosphere to the lungs to normalize Palv to atmosphere
72
pressure changes during expiration
inspiratory muscles relax causing thoracic volume and lung volume to decrease due to elastic recoil of the lungs. this increases Palv causing the air to flow out of the lungs to normalize the pressure to Patm
73
Pip during inspiration
volume of pleural cavity will increase causing Pip to decrease or become more negative
74
transpulmonary pressure
TPP = Palv - Pip
- TPP is positive under normal conditions
- higher TPP means more lung expansion (larger lung volume)
- positive TPP keeps lungs inflated and negative TPP collapses the lungs
- more negative Pip = more positive TPP = more lung expansion
75
4 physical properties of the lungs
1) compliance
2) elastance
3) surface tension
4) resistance to airflow
76
compliance of lungs
- measure of stretchability of lungs or how much effort is required to stretch the lungs
compliance = change in volume/change in TPP
- if compliance is high, less pressure difference is needed to produce lung expansion
- if compliance is low, the lung is stiffer and more pressure difference is needed to expand the lung
77
elastance of the lung
- elastic recoil of lung resists stretching and maintains the shape of the lung
- lung compliance is inversely related to elastance
- sock analogy
78
surface tension of the lung
- alveoli are lined with aqueous lining which creates surface tension which acts to collapse the lung
- smaller alveoli have higher pressure due to a smaller radius and therefore will empty air into the larger alveoli and collapse
- BUT surfactant is released by type 2 alveolar cells to reduce surface tension and equalize the pressure in alveoli
- alveoli have the same amount of surfactant but it is more concentrated in smaller alveoli
79
resistance to airflow in lung
- radius of airway is main factor affecting resistance to airflow
- first 7 branches of bronchi have the higher resistance to airflow. they have the highest radius but there is not many of them
- resistance is determined by the number of parallel pathways for airflow
80
major functions of respiration
1) replenish blood's O2 for energy production
2) remove CO2 returning from venous blood
81
2 requirements for diffusion
1) alveolar ventilation
2) pulmonary perfusion
82
alveolar ventilation
- air travels to alveolus by the path of least resistance
- air can also be ventilated through collateral pathways
83
channels for collateral ventilation
1) interbronchiolar
2) bronchoalveolar
3) alveolar pores
- there is little airflow through these channels during normal ventilation because resistance is higher
- in newborns, alveolar pores are not developed so they go into resp. distress easier
84
techniques to recruit collateral channels for ventilation
- large inspiratory volume (deep breathing)
- breath holds
this causes resistance to decrease in collateral channels
85
dead space ventilation
volume of air that does not participate in respiration
2 types:
1) anatomical dead space
2) physiological dead space
86
anatomical dead space
- volume of air that fills the conducting airways
- ~30% of tidal volume (~150ml)
87
physiological dead space
- total dead space (anatomical + alveolar dead space)
- alveolar dead space is the volume of air that is in the alveoli but does not participate in gas exchange because the alveoli are not perfused
- in healthy people alveolar dead space is negligible
- i.e. pulmonary embolism
88
alveolar minute ventilation (VA)
fresh air that reaches the alveoli per minute
VA = [VT - dead space] x RR
calculates the volume of air that participates in gas exchange
89
pulmonary perfusion
blood leaves right atrium, picks up O2 at lungs and enters left atrium
90
ventilation-perfusion matching
ventilation and perfusion must be tightly matched for efficient gas exchange (1:1 ideally)
VA/Q = 0.8 in normal lung
91
why are alveoli more perfused in an upright lung?
when lying, the weight and gravity of the lung increases the Pip at the base (less negative) meaning there is less expansion of the lung and less functional residual capacity and TPP will be lower
when upright, Pip is more negative which will increase TPP meaning more lung expansion and increased functional residual capacity
gravity will also pull blood to the bases of the lungs in an upright position
this will increase alveolar ventilation and increase perfusion
92
what does a high V/Q ratio at the apex mean?
~3.0
more ventilation than perfusion
93
what does a low V/Q ratio at the base mean?
~ 0.6
more perfusion than ventilation
94
V/Q in side lying
in side lying, the bottom lung will receive optimal V/Q matching
95
V/Q mismatch
means there is either decreased ventilation or perfusion (blood flow) due to pathological changes affecting airways, alveoli, or pulmonary vasculature
96
hypoxemia vs. hypoxia
hypoxemia: occurs when levels of O2 in arterial blood are lower than normal
hypoxia: inadequate O2 supply to tissues
97
what is the net effect of V/Q mismatc?
ALWAYS reduced gas exchange efficiency
98
what is normal SaO2?
97%
99
how is SaO2 measured?
arterial blood gases (ABGs)
100
what will SaO2 cause?
central cyanosis.
different from peripheral cyanosis where SaO2 is normal
101
oxyhemoglobin dissociation curve
- shows relationship between O2 saturation of hemoglobin and arterial pressure of O2
- Hb has changing affinity to O2 which causes sigmoidal shape to curve
- when PaO2 < 80mmHg, SaO2 drops more quickly meaning O2 is released more readily from Hb (reduced affinity)
102
pulse oximeter
- SpO2
- indirect measure of blood oxygenation
103
what is considered a red flag with a pulse oximeter?
SpO2 90% or less
104
changes in hemoglobin affinity
if curve shifts to right, Hb affinity is decreased and Hb gives up O2 easier
if curve shifts to the left, Hb affinity increases and Hb holds onto O2 easier
105
factors affecting Hb affinity
- increased temperature
- decreased pH (increased H+)
- increased PCO2
all will shift curve to right and decrease Hb affinity
106
how is CO2 transported in blood?
1) dissolved in plasma
2) carbaminhemoglobin
3) dissolved in bicarbonate (HCO3-) MAIN WAY!!!!!
107
types of pulmonary function tests
1) spirometry (most common)
2) body plethysmography
3) diffusion capacity of the lung for carbon monoxide
108
spirometry
- measures volume against time (how much air and how fast)
- patients asked to take a maximal inhalation and then a maximal exhalation as quick as possible
measurements include:
- forced expiratory volume in 1 sec (FEV1)
- forced vital capacity (FVC) = IR + ER + TV = total volume forcefully expired from the lungs
- ratio between FEV1 and FVC
results help distinguish between a restrictive and obstructive disease
109
arterial blood gas (ABG) analysis
- assesses patient's respiratory and metabolic state
- provides insight for oxygenation and acid-base balance
- obtained from blood sample from radial artery or radial arterial line
110
categories of hypoxemia based on ABGs
normal: 80-100mmHg
mild hypoxemia: 60-80mmHg
moderate hypoxemia: 40-60mmHg
severe hypoxemia: <40mmHg
111
steps for interpreting ABGs
1) assess pH
2) assess PaCO2
3) assess HCO3- (bicarbonate)
4) determine primary disorder
5) check for compensation
6) review oxygenation (normal SaO2 is 94-100%)
