Final Flashcards
(115 cards)
1
Q
In what situation can we make the intraplural pressure positive?
A
- forced expiration, Use abdominals or internal intercostals
- COUGHING
2
Q
At what week does the respiratory diverticulum (lung bud) appear as an outgrowth from the ventral wall of the foregut?
A
week 4
3
Q
The appearance and location of the lung bud are dependent upon an increase in what?
A
retinoic acid
4
Q
Increase in retinoic acid causes upregulation of _________, expressed in the endoderm of the gut tube at the site of the respiratory diverticulum?
A
TBX4
5
Q
The epithelium of the internal lining of the larynx, trachea, and bronchi, as well as that of the lungs is entirely of what origin?
A
Endoderm
6
Q
The cartilaginous, muscular, and connective tissue components of the trachea and lungs are derived from _________, which surrounds the foregut?
A
Splanchnic mesoderm
7
Q
What separates the respiratory diverticulum from the foregut when it expands caudally?
A
2 tracheoesophageal ridges
8
Q
What muscles are used for inspiration during certain circumstances (e.g. exercise) besides the diaphragm and external intercostals?
A
- Scalene: raise 1st and 2nd ribs
- Sternomastoids: raise sternum
- Some muscles in head and neck
9
Q
What is an abnormality in the partitioning of the esophagus called?
A
esophageal atresia with or without tracheoesophageal fistulas (TEFs)
10
Q
What abnormality with amniotic fluid often detected by ultrasound can be an indicator for a TEF?
A
Polyhydramnios because the amniotic fluid when swallowed does not pass to the stomach and intestines
11
Q
How many secondary bronchi develop in the right and left lungs respectively?
A
3, 2
12
Q
How many tertiary (segmental) bronchi develop in the right and left lung respectively?
A
10, 8
13
Q
At what stage of development are sufficient numbers of mature alveolar sacs and capillaries present to guarantee adequate gas exchange to allow survival?
A
7 months
14
Q
What do type II alveolar cells do?
A
produce surfactant
15
Q
Explain the roles of surfactant and macrophages in preparation for labor and delivery.
A
- surfactant enters amniotic fluid and acts on macrophages.
- These macrophages migrate across the chorion to the uterus to produce immune proteins including IL-1beta
- This leads to increased production of prostaglandins that cause uterine contractions
16
Q
What is the cause of respiratory distress syndrome?
A
- insufficient surfactant
- -Surfactant decreases the risk of respiratory distress syndrome because it prevents alveolar collapse by keeping the air-water (blood) surface membrane tension low
17
Q
how is respiratory distress syndrome treated?
A
- Treat the preterm babies with artificial surfactants
- Treat mothers with premature labor with glucocorticoids to stimulate surfactant production
18
Q
Why does the fetus engage in breathing movements in utero?
A
- This is important for stimulation of lung development
- This conditions the respiratory muscles
19
Q
How do ectopic lung buds form?
A
It is believed that these are formed from additions respiratory buds of the foregut that develop independent of the main respiratory system
20
Q
What is the term that describes the difference between the pressure volume curves for inspiration and expiration?
A
hysteresis
21
Q
What causes hysteresis?
A
Surfactant
-size of alveoli and position of surfactant causes molecules to not follow the same path
22
Q
In a normal person what is the ratio of FEV1;FVC?
A
80%
23
Q
What will the ratio of FEV1:FVC be in a person with obstructive disease (asthma or emphasema)?
A
70% or less
24
Q
What will the ratio of FEV1:FVC be in a person with a restrictive disease (interstitial fibrosis)?
A
> 90%
25
What respiratory center is believed to be the site which generates the timing (frequency) of the respiratory rhythm?
Pre-Botzinger complex
26
Failure to turn inspiration off
Apneusis
27
What respiratory group tells inspiration when to turn off?
Pontine respiratory group (PRG)
28
What respiratory group mostly tells the phrenic nerve what to do and is mostly involved in inspiration?
Dorsal respiratory group
29
What respiratory group is involved in inspiration and not only helps control the phrenic nerve but also controls the accessory muscles?
Rostral part of Ventral Respiratory Group (VRG)
30
What respiratory group provides premotor to the upper airway and other muscles of expiration?
Caudal regions of the ventral respiratory group
31
Absence of respiratory effort (no inspiration)
Apnea
32
What causes Apneusis?
Pontine damage
33
what causes Apnea?
medullary or spinal damage
34
What 3 factors increase the firing of a chemoreceptor?
- INCREASE in CO2
- DECREASE in O2
- INCREASE in H+
35
Explain how chemoreceptors on the ventral portion of the medulla are indirectly sensitive to CO2 in the blood?
- CO2 crosses BBB
- reacts with water via carbonic anhydrase
- creates H+ and HCO3 in CSF
- Chemoreceptors respond to the CSF H+
- IMPORTANT NOTE!! arterial CO2 is activating these but indirectly
36
What neurotransmitter do the peripheral chemoreceptors use?
Dopamine
37
Which chemoreceptors are faster? Peripheral or central?
Peripheral
38
Which chemoreceptors are responsible for respiratory drive?
Central
39
Fibers of the pulmonary stretch receptors travel to the brain via what?
Vagus nerve
40
What is the effect of increased firing rate of pulmonary stretch receptors?
Turn off inspiration and prolongation of expiration
41
The slowly adapting pulmonary stretch receptors are important for controlling respiration in what?
- infants
| - Adults during exercise
42
What are the rapidly adapting pulmonary stretch receptor sensitive to?
Irritation; foreign bodies in the airway; stretch
43
What is the effect of increased firing of the rapidly adapting pulmonary stretch receptors?
Cough
44
What are J receptors sensitive to and where are they located?
Pulmonary edema; Near blood vessels of alveoli
45
What is the effect of increased firing of a J receptor?
Cough or tachypnea (rapid shallow breathing)
46
How do the kidneys compensate for a respiratory acidosis and what are the results of this compensation?
- secrete H+ and reabsorb HCO3
| - Result: increases plasma bicaronate levels
47
What do the kidneys do to compensate for respiratory alkalosis and what are the results?
- reabsorbing H+ and excreting HCO3
| - Result: decreases in plasma bicarbonate levels
48
What is the expected bicarbonate equation for an ACUTE respiratory acidosis?
[HCO3]=24 + ((PaCO2 - 40)/10)
49
What is the expected bicarbonate equation for a CHRONIC respiratory acidosis?
[HCO3]=24 + 4((PaCO2 - 40)/10)
50
What is the expected bicarbonate equation for a ACUTE respiratory alkalosis?
[HCO3]=24 - 2((40 - PaCO2)/10)
51
What is the expected bicarbonate equation for a CHRONIC respiratory alkalosis?
[HCO3]=24 - 5((40 - PaCO2)/10)
52
What is the equation for decided if the respiratory compensation for a metabolic acidosis is adequate?
expected PaCO2=(1.5[HCO3] + 8) +/- 2
53
Anion Gap equation
Anion Gap=[Na] - ([Cl] + [HCO3])
54
What should the number be for a normal anion gap?
= 12
55
What are the important unmeasured chemicals to remember that make the anion gap greater than 12 in the MUDPILES mnemonic?
D: diabetic ketoacidosis, starvation or alcoholic ketoacidosis
L: lactic acidosis
S: salicylates
56
What is the equation to see if the respiratory compensation for for metabolic alkalosis is adequate?
change in PaCO2=(.5 to 1) x change in HCO3
57
Standard chest images obtained in radiagraphs are what view?
PA or lateral
58
What are the problems with taking a chest radiograph from the AP view?
- More magnification so less sharp
| - Patients unable to take deep inspiration so lung less expansion
59
What are the ABCs in interpretting a chest radiograph?
```
Airway
Breathing, Borders and Bones
Circulation and Contours
Diaphragm
Everything Else
```
60
On a chest radiograph, during a full inspiration where should the diaphragm be observed?
- 8th to 10th ribs posteriorly
| - 5th to 6th rib anteriorly
61
How much space in the thorax should the heart normally occupy?
No more than 50% of the width of the thorax
62
Describe the respiratory epithelium
Pseudostratified ciliated epithelium with goblet cells, supported by a lamina propria with seromucous glands and a rich superficial venous plexus
63
What warms incoming air?
blood in the venous plexus
64
What moistens the incoming air?
secretions of the seromucous glands and goblet cells
65
What do the superior, middle and inferior conchae do?
Create turbulence to help warm and moisten the air
66
What are the paranasal sinuses lined by?
thin pseudostratified columnar ciliated epithelium with few goblet cells
67
What is the purpose of the cilia?
beat to remove unwanted materials backwards into pharynx to be removed via GI system
68
Secretory cell at the end of the conducting airway in the terminal bronchioles
Clara cells
69
What is in Mucus?
- Mucins
- antimicrobial molecules (defensins, lysozyme, and IgA)
- Immunomodulatory molecules (secretoblobin and cytokines)
- Protective molecules (trefoil proteins and heregulin)
70
- Abnormally thick mucus by GI and respiratory glands
- Inherited mutations of CFTR which results in defective transport of Cl- and increased Na+ absorption
- bacterial infections
- cough, purulent secretions, and dyspnea
Cystic Fibrosis
71
Cells that rest on the basal lamina, but do not extend to the lumen and act as stem cells to give rise to ciliated epithelium and may give rise to goblet cells
Basal cells
72
Cells that rest on the basal lamina but do not extend to the lumen which produce a variety of peptide hormones (serotonin, somatostatin, calcitonin, ADH, ACTH), may give rise to TUMORS
Neuroendocrine cells (cells of kulchitsky)
73
Smoker's epithelium changes from pseudostratified ciliated columnar to what? and why? What are the consequences of this change?
stratified squamous
- thicker and more protective
- Not particularly good at picking up inhaled particulate matter
- not a good mucous layer and no cilia
- Increases goblet cells because these are trying to compensate
74
What holds the trachea open?
C shapes rings of hyaline cartilage
75
What is found on the posterior part of the trachea and why?
- Fibroelastic ligament - prevents overdistension of the lumen
- trachealis muscle - smooth muscle that results in narrowing during cough reflex - small diamter increases velocity of expired air
76
Once the trachea bifurcates at the carina into the left and right main bronchi, how does it's structure change?
- C-shaped cartilage breaks down into cartilage plates and smooth muscle bundles shift between the mucosa and the cartilage plates
- Aggregates of lymphoid tissue are observed in the wall of intrapulmonary bronchi, known as BALT (bronchial associated lymphoid tissue)
77
As bronchi turn to bronchioles, describe the histological changes?
- epithelium reduces thickness
- number of goblet cells reduced-replaced by clara cells in terminal bronchioles
- epithelium becomes simple ciliated columnar
- Lamina propria becomes dominated by a spiraling layer of muscularis mucosa
- cartilage and glands disappear
- reduction of diameter
78
What is the difference between goblet and clara cells?
Clara cells produce a less viscous secretion
79
A terminal bronchiole and the associated regions of pulmonary tissues that it supplies?
pulmonary lobule
80
When u transition from a terminal bronchiole to a respiratory bronchiole, what begins to appear?
alveoli - gas exchange can occur
81
Club (clara cells) produce what?
surfactant that differs from that produced by type II alveolar cells
82
After airway injury, clara or club cells can do what?
proliferate and migrate to replenish alveolar epithelial cells - known as alveolar bronchiolization
83
Club or clara cells can engulf airborne toxins and break them down via what?
cytochrome P-450 enzymes (CYP4B1) present in their endoplasmic reticulum
84
Resistance=?
(9nL)/r^4
n: viscosity
L: length of tube
r: radius of tube
85
J=?
[SA x D x (P1-P2)]/distance
J: diffusion rate in ml/min
D: diffusion coefficient for each gas
(P1-P2): pressure gradient across alveolar membrane
SA: surface are available for diffusion
distance: diffusion distance (thickness of alveolar barrier)
86
What is the normal resting value of J (how much gas is exchanged every minute) for oxygen?
250 ml/min
87
What is the normal resting value of J (how much gas is exchanged every minute) for CO2?
200 ml/min
88
Describe the interalveolar septa?
two simple squamous epithelial layers with the interstitium (nonfenestrated cappillaries embedded in an elastic connective tissue) between them
89
Type I alveolar cells represent ______ of the alveolar epithelial cell population and cover _______ of the alveolar surface?
- 40%
| - 90%
90
Type II alveolar cells cover _____ of the cells and _____ of the alveolar surface?
- 60%
| - 10%
91
Cells in interstitium that clean up debris and can also phagocytize RBC's when they get into the lungs due to heart failure?
Alveolar macrophages (dust cells)
92
During rest, how much blood is in pulmonary capillaries?
70 ml
93
During exercise, how much blood can be in pulmonary capillaries?
up to 200 ml
94
Elastase can destroy elastic tissue by being released by neutophils present in the alveolar lumen. What neutralizes elastase?
Serum alpha1-antitrypsin (serum trypsin inhibitor)
95
The loss of elastic fibers due to elastase is called what?
Emphysema
96
A form of pulmonary edema that causes acute respiratory failure from increased permeability of the alveolocapillary membrane
Acute respiratory distress syndrome (ARDS)
97
Collagen being inappropriately deposited in the interstitium of the lungs
Pulmonary interstitial fibrosis
98
What is the diffusion capacity of the lung for oxygen in a normal individual at rest?
21 O2/min/mm Hg
99
DLO2=?
1.23 x DLCO
100
Diffusion capacity of oxygen is determined by measuring what?
The diffusion capacity of CARBON MONOXIDE (CO)
101
What is the diffusion capacity of the lung for Carbon Dioxide in a normal individual at rest?
~400 ml CO2/min/mm Hg
102
What stage of lung development does a fetus become viable due to formation of respiratory bronchioles and primitive alveoli and what weeks does this occur?
```
Canalicular stage (17-26 weeks)
-cutoff is 24 weeks
```
103
Laplace's Law:
Pressure=2T/r
T: surface tension
r: radius
104
Above what Pressure of O2, on the normal Hb curve is the Hb more than 90% saturated?
60 mmHg
105
If the A-a gradient is greater than this, there is a problem with the alveoli.
20 mm Hg
106
What causes ectopic endodermal budding, tracheoesophageal fistulas, and ectopic TBX4 expression?
Misexpression of FGF10
107
Incomplete expansion or collapse of parts of or a whole lung?
Atelectasis
108
Inadequate oxygen available for use by the tissues
hypoxia
109
Total absence of oxygen being delivered to the tissue
Anoxia
110
Low oxygen content in the blood
hypoxemia
111
Form of hypoxia where PaO2 is below normal. Also name causes
Hypoxic hypoxia
| -Lung diseases with diffusion impairments such as emphysema or fibrosis
112
Form of hypoxia where the lungs are perfectly normal but the oxygen carrying capacity of blood has been reduced. Also name the causes
-Anemic hypoxia
| Causes: Carbon monoxide,
113
Form of hypoxia where lungs are working fine and blood can carry sufficient oxygen but the tissue is not receiving sufficient oxygen because the heart cannot pump the blood to the tissue (or arteries are blocked). Give causes
Circulatory hypoxia
| -Causes: sickle cell anemia
114
Form of hypoxia where there is no problem getting the oxygen to the tissues however the tissue is unable to use the oxygen. Give causes
Histotoxic hypoxia
| -Causes: cyanide
115
reduced FEF 25-75% is indicative of what?
early small airway obstruction
