Chapter 22 - The Respiratory System Flashcards
1
Q
The major function of the respiratory system is ___.
A
respiration
2
Q
The respiratory system plays what part in cellular respiration?
A
- supplies body with oxygen -for-
2. disposes of carbon dioxide as a waste product -of-
3
Q
The four processes of respiration involve both ___ and ___ systems.
A
respiratory; circulatory
4
Q
The respiratory system also functions in:
A
olfaction and speech
5
Q
The processes of respiration are:
A
- pulmonary ventilation
- external respiration
- transport
- internal respiration
6
Q
The processes of respiration are divided into two systems:
A
- respiratory system
2. circulatory system
7
Q
The processes of respiration in the respiratory system are:
A
pulmonary ventilation and external respiration
8
Q
The processes of respiration in the circulatory system are:
A
transport and internal respiration
9
Q
Pulmonary ventilation is:
A
(breathing)-movement of air into and out of lungs
10
Q
External respiration is:
A
O2 and CO2 exchange between lungs and blood
11
Q
Transport in respiration is:
A
O2 and CO2 in blood
12
Q
Internal respiration is:
A
O2 and CO2 exchange between systemic blood vessels and tissues
13
Q
The major organs of the respiratory system are:
A
- nose, nasal cavity, and paranasal sinuses
- pharynx
- larynx
- trachea
- bronchi and their branches
- lungs and alveoli
14
Q
The functional anatomy of the respiratory system are divided into two zones, which are:
A
- respiratory zone
2. conducting zone
15
Q
The respiratory zone is the site of:
A
gas exchange
16
Q
The microscopic structures of the respiratory zone are:
A
- respiratory bronchioles
- alveolar ducts
- alveoli
17
Q
The conducting zone acts as:
A
a conduit to gas exchange sites
18
Q
The conducting zone includes ___ structures.
A
all other respiratory
19
Q
The function of the conducting zone is:
A
cleansing, warming, and humidifying air
20
Q
____ and ___ promote ventilation.
A
Diaphragm; other respiratory muscles
21
Q
The nose’s functions are:
A
- providing an airway for respiration
- moistening and warming entering air
- filtering and cleaning inspired air
- serving as a resonating chamber for speech
- housing olfactory receptors
22
Q
The two regions of the nose are:
A
external nose and nasal cavity
23
Q
External nose structures:
A
- root
- bridge
- dorsum nasi
- apex
- philtrum
- nares (nostrils)
24
Q
shallow vertical groove inferior to nose apex
A
philtrum
25
nares are bounded laterally by:
alae
26
The nasal cavity is located:
within and posterior to external nose
27
structures of the nasal cavity
1. nasal septum
2. posterior nasal apertures (chonchae)
3. roof-ethmoid and sphenoid bones
4. on floor-hard (bone) and soft palates (muscle)
28
the nasal cavity is divided midline by
the nasal septum
29
these open into the nasal pharynx
posterior nasal apertures (chonchae)
30
nasal cavity structures (continued)
- nasal vestibule
- nasal conchae
- nasal meatus
31
part of the nasal cavity superior to the nostrils
nasal vestibule
32
the nasal vestibule contains:
vibrissae (hairs)
33
function of vibrissae
to filter coarse particles from inspired air
34
The rest of the nasal cavity is lined with mucous membranes, which are:
1. olfactory mucosa
| 2. respiratory mucosa
35
Olfactory mucosa contains _____.
olfactory epithelium
36
cell structure of respiratory mucosa
pseudostratified ciliated columnar epithelium
37
mucous and serous secretions of respiratory mucosa contain:
lysozyme and defensins
38
function of the cilia of respiratory mucosa
move contaminated mucus posteriorly to throat
39
inspired air is warmed by ____ of respiratory mucosa
plexuses of capillaries and veins
40
____ trigger sneezing in respiratory mucosa
sensory nerve endings
41
Nasal conchae protrudes ____ from ____.
medially; lateral walls
42
functions of nasal conchae
- increase mucosal area
| - enhance air turbulence
43
groove inferior to each nasal concha
nasal meatus
44
During inhalation, nasal conchae and nasal mucosa do what?
filter, heat, and moisten air
45
During exhalation, nasal conchae and nasal mucosa do what?
reclaim heat and moisture
46
the paranasal sinuses are located
in frontal, sphenoid, ethmoid, and maxillary bones
47
functions of the paranasal sinuses
1. lighten skull
2. secrete mucus
3. help to warm and moisten air
48
Homeostatic imbalance of nasal mucosa leads to
rhinitis
49
inflammation of nasal mucosa
rhinitis
50
in rhinitis, nasal mucosa is continuous with mucosa of the respiratory tract, which leads to
spreading from the nose to the throat to the chest
51
in rhinitis, nasal mucosa also spreads to
tear ducts and paranasal sinuses
52
when nasal mucosa spreads to tear ducts and paranasal sinuses in rhinitis, what happens?
blocked sinus passageways
- -> air absorbed
- -> vacuum
- -> sinus headache
53
muscular tube from base of skull to C6
pharynx
54
the pharynx connects
nasal cavity and mouth to larynx and esophagus
55
the pharynx is composed of
skeletal muscle
56
The three regions of the pharynx are:
1. nasopharynx
2. oropharynx
3. laryngopharynx
57
air passageway posterior to nasal cavity
nasopharynx
58
the lining of the nasopharynx is:
pseudostratified columnar epithelium
59
___ and ___ close nasopharynx during swallowing.
soft palate; uvula
60
The nasopharynx extends from ____, to ____, to ____.
pharyngeal tonsil; pharyngotympanic tube; uvula
61
located on the posterior wall of the nasopharynx
pharyngeal tonsil
62
pharyngeal tonsil is also called
adenoids
63
function of pharyngotympanic tubes
drain and equalise pressure in middle ear
64
pharyngotympanic tubes open into ___ walls
lateral
65
pharyngotympanic tubes are also called
auditory
66
passageway for food and air
oropharynx
67
food and air passageway of the oropharynx extends from the level of ___ to ____.
soft palate; epiglottis
68
the oropharynx has a lining of
stratified squamous epithelium
69
opening to oral cavity is called
isthmus of fauces
70
these are located in lateral walls of fauces
palatine tonsils
71
located on the posterior surface of the tongue
lingual tonsil
72
the ___ is also a passageway for food and air
laryngopharynx
73
the laryngopharynx is posterior to
upright epiglottis
74
the laryngopharynx extends to ____, where it is continuous with ___.
larynx; esophagus
75
the laryngopharynx is lined with
stratified squamous epithelium
76
The larynx attaches to
hyoid bone
77
The larynx opens into
laryngopharynx
78
The larynx is continuous with
trachea
79
Functions of the larynx are:
- provides patent airway
- routes air and food into proper channels
- voice production (houses vocal cords)
80
The larynx is all ___ cartilage except for the epiglottis.
hyaline
81
The different cartilages of the larynx are:
1. thyroid cartilage
2. cricoid cartilage
3. paired arytenoid
4. paired cuneiform
5. paired corniculate
6. elastic cartilage (epiglottis)
82
The thyroid cartilage of the larynx has
laryngeal prominence (Adam's apple)
83
the elastic cartilage of the epiglottis covers
laryngeal inlet during swallowing
84
the epiglottis is covered in
taste bud-containing mucosa
85
located deep to laryngeal mucosa
vocal ligaments
86
Vocal ligaments attach ___ to ____.
arytenoid cartilages; thyroid cartilage
87
vocal ligaments contain ___ fibres.
elastic
88
vocal ligaments form the core of:
vocal folds (true vocal cords)
89
opening between vocal folds
glottis
90
vocal folds produce sound by
vibration as air rushes up from lungs
91
Vestibular folds are ___ vocal cords.
false
92
Vestibular folds are located
superior to vocal folds
93
Do vestibular folds play a part in sound production?
no
94
Vestibular folds help to close what?
glottis during swallowing
95
The epithelium of the superior portion of the larynx is
stratified squamous epithelium
96
The epithelium inferior to vocal folds of the larynx is
pseudostratified ciliated columnar epithelium
97
How is speech produced?
by intermittent release of expired air while opening and closing glottis
98
Voice pitch is determined by
length and tension of vocal cords
99
Loudness of voice is determined by
force of air upon vocal cords
100
Chambers of ___ amplify and enhance sound quality.
- pharynx
- oral
- nasal
- sinus
cavities
101
Sound is "shaped" into language by muscles of:
1. pharynx
2. tongue
3. soft palate
4. lips
102
vocal folds of larynx may act to prevent air passage as
sphincter
103
an example of acting as sphincter
Valsalva's manoeuvre
104
Process of Valsalva's manoevre
- glottis closes to prevent exhalation
- -> abdominal muscles contract
- -> intra-abdominal pressure rises
- -> helps to empty rectum or stabilises trunk during heavy lifting
105
the trachea is also known as
windpipe
106
the trachea extends from
larynx into mediastinum
107
The treacheal wall is composed of three layers:
1. mucosa
2. submucosa
3. adventitia
108
structure of mucosa in trachea
ciliated pseudostratified epithelium with goblet cells
109
structure of submucosa in trachea
connective tissue with seromucous glands
110
structure of adventitia in trachea
- outermost layer is made of connective tissue
| - encases C-shaped rings of hyaline cartilage
111
the trachealis muscle connects
posterior parts of cartilage rings
112
trachealis muscle contracts when?
during coughing to expel mucus
113
spar of cartilage on last, expanded tracheal cartilage
carina
114
the carina is the point where the trachea branches into
two main bronchi
115
Air passages undergo how many orders of branching? What is this known as?
23; bronchial (respiratory) tree
116
Process of air passage from bronchial tree
- tips of bronchial tree
- ->conducting zone structures
- ->respiratory zone structures
117
The trachea branches into
right and left main (primary) bronchi
118
Each main bronchus enters ___ of one lung.
hilum
119
Right main bronchus is more ___ than left.
- wider
- shorter
- more vertical
120
Each main bronchus branches into
lobar (secondary) bronchi
121
There are ___ lobar bronchi on right, ___ on left.
three; two
122
Each lobar bronchus supplies
one lobe
123
Each lobar bronchus branches into
segmental (tertiary) bronchi
124
Segmental bronchi divide
repeatedly
125
Bronchi branches become smaller and smaller into
1. bronchioles
| 2. terminal bronchioles
126
size of bronchioles
less than 1 mm in diameter
127
size of terminal bronchioles
smallest--less than 0.5 mm in diameter
128
The conducting zone structures are
from bronchi through bronchioles
129
Structural changes occur from bronchi through bronchioles. Cartilage rings become:
irregular plates
130
in bronchioles ___ replace cartilage
elastic fibres
131
The epithelium from bronchi through bronchioles changes from ___ to ___.
pseudostratified columnar; cuboidal
132
From bronchi through bronchioles, ___ and ___ become sparse.
cilia; goblet cells
133
From bronchi through bronchioles, the relative amount of ___ increases. This allows for ____.
smooth muscles; constriction
134
The respiratory zone begins as
terminal bronchioles
135
Branches of the respiratory zone
- begins as terminal bronchioles
- ->respiratory bronchioles
- ->alveolar ducts
- ->alveolar sacs
136
Alveolar sacs contain clusters of ___.
alveoli
137
Most of the lung volume is made up of
~300 million alveoli
138
Alveoli are sites of
gas exchange
139
The respiratory membrane is composed of
- alveolar and capillary walls and their fused basement membranes
- type i alveolar cells
- type ii alveolar cells
140
the fused basement membrane of alveolar and capillary walls is approximately ____ thick
0.5 micrometres
141
the fused basement membrane of alveolar and capillary walls allows for
gas exchange across membrane by simple diffusion
142
cell type of type i alveolar cells/alveolar walls
single layer of squamous epithelium
143
cell type of type ii alveolar cells
scattered cuboidal
144
type ii alveolar cells secrete
surfactant and antimicrobial proteins
145
alveoli are surrounded by ___ and ____
fine elastic fibres; pulmonary capillaries
146
____ connect adjacent alveoli
alveolar pores
147
alveolar pores allow for
equalising air pressure throughout lung
148
____ keep alveolar surfaces sterile
alveolar macrophages
149
dead macrophages are carried by ___ to ___ to ___
cilia; throat; being swallowed
150
rate of dead macrophage carriage by cilia
2 million/hour
151
The lungs occupy all of the thoracic cavity except
mediastinum
152
The root of the lung is
site of vascular and bronchial attachment to mediastinum
153
costal surface of lung is divided into
anterior, lateral, and posterior surfaces
154
the lungs are composed mainly of
alveoli
155
lung balance is maintained by
stroma--elastic connective tissue (allows for elasticity)
156
the apex of the lung is located
superior tip; deep to clavicle
157
the base of the lung is located
inferior surface; rests on diaphragm
158
the hilum of the lung is located
on mediastinal surface
159
the hilum of the lung is site for
entry/exit of blood vessels, bronchi, lymphatic vessels, and nerves
160
the ___ lung is smaller than the ___
left; right
161
concavity of lung for heart
cardiac notch
162
the left lung is separated into lobes by
oblique fissure
163
lobes of the left lung
- superior
| - inferior
164
the right lung is separated into lobes by
oblique and horizontal fissures
165
lobes of the right lung
1. superior
2. middle
3. inferior
166
the lungs contain
- bronchopulmonary segments
| - lobules
167
amount of bronchopulmonary segments in right lung
10
168
amount of bronchopulmonary segments in left lung
8-10
169
bronchopulmonary segments in lungs are separated by
connective tissue septa
170
if bronchopulmonary segments are diseased
they can be individually removed
171
smallest subdivisions in the lungs visible to the naked eye
lobules
172
lobules are served by
bronchioles and their branches
173
circulation with low pressure and high volume
pulmonary
174
_____ deliver systemic venous blood to lungs for oxygenation
pulmonary arteries
175
pulmonary arteries branch profusely and feed into
pulmonary capillary networks
176
___ carry oxygenated blood from respiratory zones to the heart
pulmonary veins
177
Lung capillary endothelium contains
enzymes that act on substances in blood
178
Example of enzyme lung capillary endothelium contains
angiotensin-converting enzyme--activates blood pressure hormone
179
____ provide oxygenated blood to lung tissue
bronchial arteries
180
bronchial arteries arise from ___ and enter lungs at ___.
aorta; hilum
181
bronchial arteries are part of ___ circulation
systemic (high pressure, low volume)
182
bronchial arteries supply all lung tissue except
alveoli
183
bronchial veins anastomose with
pulmonary veins
184
Pulmonary veins carry
most venous blood back to heart
185
thin, double-layered serosa
pleurae
186
pleurae divides this into
thoracic cavity; two pleural compartments and mediastinum
187
the pleural compartments of the thoracic cavity are
1. parietal
| 2. visceral
188
location of parietal pleura
- on thoracic wall
- superior face of diaphragm
- around heart
- between lungs
189
location of visercal pleura
on external lung surface
190
___ fills pleural cavity
pleural fluid
191
pleural fluid in pleural cavity allows for
- lubrication and surface tension
| - assists in expansion and recoil
192
pulmonary ventilation consists of two phases
1. inspiration
| 2. expiration
193
pressure exerted by air surrounding body
atmospheric pressure (Patm)
194
1 atm is equal to
760 mm Hg at sea level
195
____ are described relative to Patm
respiratory pressures
196
pressure less than Patm
negative respiratory pressure
197
pressure greater than Patm
positive respiratory pressure
198
pressure equal to Patm
zero respiratory pressure
199
pressure in alveoli
intrapulmonary (intra-alveolar) pressure (Ppul)
200
Intrapulmonary pressure fluctuates with
breathing
201
Intrapulmonary pressure always eventually
equalises with Patm
202
pressure in pleural cavity
intrapleural pressure (Pip)
203
intrapleural pressure fluctuates with
breathing
204
Intrapleural pressure is always
a negative pressure (< Patm and < Ppul)
205
Fluid level of intrapleural pressure must be
minimal
206
Fluid is pumped out of the pleural cavity by
lymphatics
207
If fluid accumulates in pleural cavity, what happens to intrapleural pressure?
it becomes positive, and lung collapses
208
Negative intrapleural pressure is caused by
opposing forces
209
Two inward forces of intrapleural pressure promote
lung collapse
210
inward forces of intrapleural pressure that promote lung collapse are
- elastic recoil of lungs decreases lung size
| - surface tension of alveolar fluid reduces alveolar size
211
one outward force of intrapleural pressure tends to enlarge lungs, which is
elasticity of chest wall pulls thorax outward
212
lungs collapse if
Pip is equal to Ppul or Patm
213
transpulmonary pressure equation
Ppul - Pip
214
what does transpulmonary pressure do
keeps airways open
215
greater transpulmonary pressure leads to
larger lungs
216
lung collapse due to plugged bronchioles
atelectasis
217
when bronchioles are plugged in atelectasis, what happens?
alveoli collapse by using up what is left of oxygen
218
air in pleural cavity is called
pneumothorax
219
Pneumothorax is "caught" by
-wound in parietal pleura
or
-rupture of visceral pleura
220
Pneumothorax is treated by
removing air with chest tubes; pleurae heal, lung reinflates
221
Pulmonary ventilation is regulated by
inspiration and expiration
222
Pulmonary ventilation is made up of mechanical processes that depend on
volume changes in thoracic cavity
223
Volume changes of thoracic cavity lead to
pressure changes
224
Pressure changes of thoracic cavity lead to
gases flowing to equalise pressure
225
relationship between pressure and volume of a gas
Boyle's Law
226
when gases fill container, if container size is reduced, it leads to
increased pressure
227
pressure varies ___ with volume
inversely
228
formula for Boyle's Law
P1V1 = P2V2
229
inspiration is ___ process
active
230
during inspiration, inspiratory muscles
contract
231
inspiratory muscles of inspiration are
diaphragm and external intercostals
232
after inspiratory muscles contract during inspiration, what happens?
thoracic volume increases --> intrapulmonary pressure drops (to -1 mm Hg)
233
during inspiration, lungs are ____ and intrapulmonary volume ___
stretched; increases
234
during inspiration, air flows into lungs, down its pressure gradient, until
Ppul = Patm
235
forced inspiration is characteristic of
vigorous exercise, COPD
236
process of forced inspiration
- accessory muscles (scalenes, sternocleidomastoid, pectoralis minor)
- ->further increase in thoracic cage size
237
quiet expiration is normally a ___ process
passive
238
during expiration, inspiratory muscles
relax
239
during expiration, thoracic cavity volume
decreases
240
during expiration, elastic lungs ____ and intrapulmonary volume ___
recoil; decreases
241
when elastic lungs recoil and intrapulmonary volume decreases in expiration, what happens?
pressure increases (Ppul rises to +1 mm Hg)
242
after pressure increases during expiration, what happens?
air flows out of lungs down its pressure gradient until Ppul = 0
243
forced expiration is a ___ process
active
244
forced expiration uses ___ and ___ muscles
abdominal (oblique and transverse); internal intercostal muscles
245
Three factors hinder air passage and pulmonary ventilation and require energy to overcome:
1. airway resistance
2. alveolar surface tension
3. lung compliance
246
a major nonelastic source of resistance to gas flow; occurs in airways
friction
247
Relationship between flow (F), pressure (P), and resistance (R) is:
F = delta P/ R
248
pressure gradient between atmosphere and alveoli
delta P
249
delta P is usually ____ during normal quiet breathing
2 mm Hg or less
250
gas flow changes inversely with
resistance
251
resistance in airway is usually significant or insignificant?
insignificant
252
airway resistance is usually insignificant because ___ are in first part of conducting zone
large airway diameters
253
airway resistance is usually insignificant because of this in airways as they branch
they get smaller, increasing total cross-sectional area
254
resistance is greatest in
medium-sized bronchi
255
Resistance disappears at
terminal bronchioles
256
why does resistance disappear at terminal bronchioles
diffusion drives gas movement
257
as airway resistance rises, breathing movements become
more strenuous
258
severe constriction or obstruction of bronchioles can
- prevent life-sustaining ventilation
| - occur during acute asthma attacks; stops ventilation
259
what does epinephrine do to bronchioles and how does this affect air resistance?
it dilates bronchioles and reduces air resistance
260
surface tension of alveoli attracts
liquid molecules to one another at gas-liquid interface
261
surface tension of alveoli resists any force that tends to
increase surface area of liquid
262
is the surface tension of alveoli liquid-high or gas-high?
liquid (water-high)
263
water-high surface tension of alveoli coats ___ to do what?
alveolar walls; reduce them to smallest size
264
detergent-like lipid and protein complex
surfactant
265
surfactant is produced by
type II alveolar cells
266
surfactant reduces
surface tension of alveolar fluid
267
surfactant discourages
alveolar collapse
268
insufficient quantity of surfactant in premature infants causes
infant respiratory distress syndrome
269
what happens in infant respiratory distress syndrome?
alveoli collapse after each breath
270
the measure of change in lung volume that occurs with given change in transpulmonary pressure
lung compliance
271
higher lung compliance -->
easier to expand lungs
272
lung compliance is normally high due to
- distensibility of lung tissue
| - alveolar surface tension
273
lung compliance is diminished by
- nonelastic scar tissue replacing lung tissue (fibrosis)
- reduced production of surfactant
- decreased flexibility of thoracic cage
274
homeostatic imbalances that reduce compliance are
- deformities of thorax
- ossification of costal cartilage
- paralysis of intercostal muscles
275
respiratory volumes used to assess respiratory status are
1. tidal volume (TV)
2. inspiratory reserve volume (IRV)
3. expiratory reserve volume (ERV)
4. residual volume (RV)
276
respiratory capacities are combinations of
respiratory volumes
277
the different respiratory capacities
- inspiratory capacity (IC)
- functional residual capacity (FRC)
- vital capacity (VC)
- total lung capacity (TLC)
278
anatomical dead space's contribution to gas exchange
none
279
anatomical dead space is the air
remaining in passageways; ~150 ml
280
non-functional alveoli due to collapse or obstruction
alveolar dead space
281
sum of anatomical and alveolar dead space
total dead space
282
instrument for measuring respiratory volumes and capacities
spirometer
283
spirometry can distinguish between
1. obstructive pulmonary disease
| 2. restrictive disorders
284
increased airway resistance can lead to
obstructive pulmonary disease (e.g. bronchitis)
285
reduced total lung capacity due to disease or fibrosis can lead to
restrictive disorders
286
in obstructive pulmonary disease what may change?
TLC, FRC, and RV may increase
287
in restrictive disorders, what changes?
VC, TLC, FRC, and RV decline
288
To measure *rate* of gas movement, find
- forced vital capacity (FVC)
| - forced expiratory volume (FEV)
289
the gas forcibly expelled after taking a deep breath
forced vital capacity (FVC)
290
amount of gas expelled during specific time intervals of forced vital capacity
forced expiratory volume (FEV)
291
total amount of gas flow into or out of respiratory tract in one minute
minute ventilation
292
normal minute ventilation at rest is
~6 L/min
293
normal minute ventilation with exercise is
up to 200 L/min
294
minute ventilation is ___ estimate of respiratory efficiency
only rough
295
minute ventilation is a good indicatory of
effective ventilation
296
flow of gases into and out of alveoli during a particular time
alveolar ventilation rate (AVR)
297
formula for AVR
AVR = frequency x (TV - dead space)
| ml/min) (breaths/min) (ml/breath
298
dead space is normally
constant
299
rapid, shallow breathing ___ AVR
decreases
300
nonrespiratory air movements may modify
normal respiratory rhythm
301
most nonrespiratory air movements result from
reflex action; some can be voluntary
302
examples of reflex action nonrespiratory air movements
cough, sneeze, crying, laughing, hiccups, and yawns
303
diffusion of gases in lungs
external respiration
304
diffusion of gases at body tissues
internal respiration
305
both internal and external respiration involve
- physical properties of gases
| - composition of alveolar gas
306
Dalton's Law of partial pressures states that
total pressure exerted by mixture of gases = sum of pressures exerted by each gas
307
pressure exerted by each gas in mixture; directly proportional to its percentage in mixture
partial pressure
308
by Henry's Law, when gas mixtures are in contact with liquid, each gas dissolves in proportion to
its partial pressure
309
by Henry's Law, at equilibrium, partial pressures in two phases will be
equal
310
by Henry's Law, the amount of each gas that will dissolve depends on
- solubility (CO2 is 20 times more soluble in water than O2; little N2 dissolves in water)
- temperature (as temp rises, solubility decreases)
311
Alveoli contain more ____ and ____ than ____.
CO2; water vapor, atmospheric air
312
gas exchanges in
lungs
313
alveoli allow for ___ of air
humidification
314
there is a mixing of ___ with each breath
alveolar gas
315
There is an exchange of ___ across respiratory membrane in external respiration.
O2 and CO2
316
External respiration/exchange of O2 and CO2 across respiratory membrance is influenced by
- thickness and surface area of respiratory membrane
- partial pressure gradients and gas solubilities
- ventilation-perfusion coupling
317
respiratory membranes are approximately ____ thick
0.5 to 1 micrometre
318
total surface area of respiratory membranes is
large (40 times that of skin); allows for gas exchange
319
respiratory membrane thickens if
lungs become waterlogged and edematous; gas exchange becomes inadequate
320
reduced surface area of respiratory membrane is present in
- emphysema
- tumours
- inflammation
- mucus
321
partial pressure gradient for O2 in lungs is
steep
322
Venous blood PO2 =
40 mm Hg
323
Alveolar PO2 =
104 mm Hg
324
steep partial pressure gradient for O2 in lungs drives oxygen flow to
the blood
325
Equilibrium between partial pressure of alveoli and venous blood is reached across respiratory membrane in what amount of time? What does this allow for?
~0.25 sec (about 1/3 time for RBC in pulmonary capillary); adequate oxygenation even if blood flow increases 3x
326
partial pressure gradient for CO2 in lungs is
less steep than O2
327
venous blood PCO2 =
45 mm Hg
328
alveolar PCO2 =
40 mm Hg
329
the gradient for PCO2 is not as steep as PO2, but
CO2 diffuses in equal amounts with O2
330
solubility of CO2 in plasma compared to O2
20x more soluble
331
blood flow reaching alveoli
perfusion
332
amount of gas reaching alveoli
ventilation
333
ventilation and perfusion are matched (coupled) for
efficient gas exchange
334
ventilation and perfusion are never balanced for all alveoli due to
- regional variations (due to effect of gravity on blood and air flow)
- some alveolar ducts are plugged with mucus
335
in perfusion, changes in PO2 in alveoli cause changes in
diameters of arterioles
336
Where alveolar O2 is high,
arterioles dilate
337
Where alveolar O2 is low,
arterioles constrict
338
changes in PO2 in alveoli direct most blood where
alveolar oxygen is high
339
Changes in PCO2 in alveoli cause changes in
diameters of bronchioles
340
Where alveolar CO2 is high
bronchioles dilate
341
where alveolar CO2 is low
bronchioles contract
342
changes in PCO2 in alveoli allow for
elimination of CO2 more rapidly
343
Capillary gas exchanges in
body tissues (internal respiration)
344
___ and ___ are reversed in internal respiration compared to external respiration
partial pressures; diffusion gradients
345
In internal respiration, tissue PO2 is always ____ than systemic arterial blood
lower
346
In internal respiration low PO2 moves
oxygen from blood to tissues
347
In internal respiration CO2 goes from
tissues to blood
348
In internal respiration, venous blood PO2 is ____ and PCO2 is ____
40 mm Hg; 45 mm Hg
349
Molecular O2 is carried in
the blood
350
proportion of where O2 is in blood transport
- 1.5% dissolved in plasma
| - 98.5% loosely bound to each Fe and Hb in RBCs
351
hemoglobin-O2 combination
oxyhemoglobin (HbO2)
352
hemoglobin that has released O2
reduced hemoglobin (deoxyhemoglobin) (HHb)
353
O2 and hemoglobin in blood reversible reaction
HHb + O2 HbO2 + H+
354
Loading and unloading of O2 is facilitated by
shape of Hb
355
As O2 binds to Hb, Hb affinity for O2
increases
356
As O2 is released from Hb, Hb affinity for O2
decreases
357
all four heme groups carry O2
fully saturated
358
one to three hemes carry O2
partially saturated
359
Rate of loading and unloading of O2 is regulated to ensure adequate oxygen delivery to cells by
- PO2
- Temperature
- blood pH
- PCO2
- Concentration of BPG
360
produced by RBCs during glycolysis; levels rise when oxygen levels chronically lowest
BPG
361
Shape of hemoglobin saturation plotted against PO2 in a graph
S-shaped curve
362
Binding and release of O2 is influenced by
PO2
363
In arterial blood, PO2 =
100 mm Hg
364
In arterial blood, contains ____ oxygen per 100 ml blood
20 ml (20 vol %)
365
In arterial blood, HB is ___% saturated.
98
366
Further increases in PO2 (e.g. breathing deeply) produce
minimal increases in O2 binding
367
In venous blood, PO2 =
40 mm Hg
368
Venous blood contains ____% oxygen.
15 vol
369
In venous blood, Hb is ___% saturated.
75
370
Oxygen remaining in venous blood
venous reserve
371
Other factors influencing Hb saturation are
- increase in temperature
- H+
- PCO2
- BPG
372
Factors that influence Hb saturation modify structure of Hb and
decrease its affinity for O2
373
Hb saturation factors occur in
systemic capillaries
374
Hb saturation factors enhance
O2 unloading from blood
375
Hb saturation factors shift dissociation curve to
the right
376
Decrease in Hb saturation factors shift dissociation curve to
the left
377
Decrease in Hb saturation factors decreases
oxygen unloading from blood
378
As cells metabolise glucose and use O2, PCO2 and H+
increase in capillary blood
379
Declining blood pH and increasing PCO2 lead to
Bohr effect
380
with the Bohr effect, what happens?
Hb-O2 bond weakens --> oxygen unloading where needed most
381
Head production increases, then
directly and indirectly decreases Hb affinity for O2 --> increased oxygen unloading to active tissues
382
inadequate O2 delivery to tissues; this can lead to ___
hypoxia; cyanosis
383
too few RBCs; abnormal or too little Hb
anemic hypoxia
384
impaired/blocked circulation
ischemic hypoxia
385
cells unable to use O2, as in metabolic poisons
histotoxic hypoxia
386
abnormal ventilation; pulmonary disease
hypoxemic hypoxia
387
this results as a homeostatic imbalance and has a 200X greater affinity for Hb than oxygen
carbon monoxide poisoning
388
The three ways CO2 is transported in blood
- 7-10% dissolved in plasma
- 20% bound to globin of Hb
- 70% transported as bicarbonate ions in plasma
389
CO2 combines with water to form ___, which quickly dissociates
carbonic acid (H2CO3)
390
CO2 combination with water occurs primarily in RBCs, where _____ reversibly and rapidly catalyses reaction
carbonic anhydrase
391
in systemic capillaries, HCO3-
quickly diffuses from RBCs into plasma
392
When HCO3- diffuses from RBCs into plasma, ____ occurs
chloride shift
393
Outrush of HCO3- from RBCs is
balanced as Cl- moves into RBCs from plasma
394
In pulmonary capillaries, HCO3-
moves into RBCs (while Cl- moves out); binds with H+ to form H2CO3
395
In pulmonary capillaries, H2CO3 is split by
carbonic anhydrase into CO2 and water
396
In pulmonary capillaries, CO2 diffuses
into alveoli
397
Amount of CO2 transported is affected by PO2. This is called
Haldane Effect
398
Reduced Hb (less oxygen saturation) forms ___ and buffers ___ more easily.
carbaminohemoglobin; H+
399
lower PO2 and hemoglobin saturation with ___; more ___ carried in blood
O2; CO2
400
Haldane Effect encourages exchange in
tissues and lungs
401
At tissues, as more CO2 enters blood
- more oxygen dissociates from Hb (Bohr effect)
| - as HbO2 releases O2, it more readily forms bonds with CO2 to form carbaminohemoglobin
402
resists changes in blood pH
carbonic acid-bicarbonate buffer system
403
If H+ concentration in blood rises,
excess H+ is removed by combining with HCO3- --> H2CO3
404
If H+ concentration begins to drop,
H2CO3 dissociates, releasing H+
405
HCO3- is ___ of carbonic acid-bicarbonate buffer system
alkaline reserve
406
changes in respiratory rate and depth affect
blood pH
407
slow, shallow breathing -->
increased CO2 in blood --> drop in pH
408
rapid, deep breathing -->
decreased CO2 in blood --> rise in pH
409
changes in ventilation can adjust ___ when disturbed by ____
pH; metabolic factors
410
respiration involves
- higher brain centres
- chemoreceptors
- other reflexes
411
Neural controls of respiration are
neurons in reticular formation of medulla and pons
412
Clustered neurons in the medulla that are important for respiration are
1. ventral respiratory group
| 2. dorsal respiratory group
413
ventral respiratory group does what?
rhythm-generating and integrative centre
414
VRG sets ____
eupnea (12-15 breaths/min)
415
Eupnea is
normal respiratory rate and rhythm
416
Inspiratory neurons of VRG excite inspiratory muscles via ___ and ____
phrenic (diaphragm); intercostal nerves (external intercostals)
417
Expiratory neurons inhibit
inspiratory neurons
418
Dorsal respiratory group is located
near root of cranial nerve IX
419
DRG integrates input from
peripheral stretch and chemoreceptors; sends information to VRG
420
influence and modify activity of VRG
pontine respiratory centres
421
these smooth out the transition between inspiration and expiration and vice versa
pontine respiratory centres
422
Pontine respiratory centres transmit impulses to
VRG --> modify and fine-tune breathing rhythms during vocalisation, sleep, exercise
423
respiratory rhythm is hypothetically generated by
pacemaker neurons with intrinsic rhythmicity
424
Most widely accepted hypothesis for generation of respiratory rhythm is
reciprocal inhibition of two sets of interconnected pacemaker neurons in medulla generate rhythms
425
breathing depth is determined by
how actively respiratory centre stimulates respiratory muscles
426
breathing rate is determined by
how long inspiratory centre is active
427
both breathing rate and depth are modified in response to
- changing levels of CO2, O2, and H+
| - sensed by central and peripheral chemoreceptors
428
chemical factors of ___ is most potent and most closely controlled
PCO2
429
If blood PCO2 levels rise, CO2
accumulates in brain
430
when PCO2 levels rise, this is called
hypercapnia
431
when CO2 accumulates in brain,
CO2 in brain is hydrated
- ->carbonic acid
- ->dissociates, releasing H+
- ->pH drops
432
H+ stimulates
central chemoreceptors in brain stem
433
Chemoreceptors synapse with
respiratory regulatory centres
434
When chemoreceptors synapse with respiratory regulatory centres, what happens?
- increased rate and depth of breathing
- ->lower blood PCO2
- ->pH rises
435
increased depth and rate of breathing that exceeds body's need to remove CO2
hyperventilation
436
hyperventilation leads to
decreased blood CO2 levels
- -> cerebral vasoconstriction and cerebral ischemia
- ->dizziness, fainting
437
decreased blood CO2 levels is known as
hypocapnia
438
breathing cessation from abnormally low PCO2
apnea
439
chemical factors influence of PO2 are
-peripheral chemoreceptors in aortic and carotid bodies--arterial O2 level sensors
440
declining PO2 normally has ____ effect on ventilation
slight
441
When excited, peripheral chemoreceptors cause
respiratory centres to increase ventilation
442
Why does declining PO2 normally have only a slight effect on ventilation?
- huge O2 reservoir bound to Hb
| - requires substantial drop in arterial PO2 (to 60 mm Hg) to stimulate increased ventilation
443
arterial pH can modify
respiratory rate and rhythm even if CO2 and O2 levels are normal
444
arterial pH is mediated by
peripheral chemoreceptors
445
decreased arterial pH may reflect
CO2 retention; accumulation of lactic acid; excess ketone bodies
446
respiratory system controls attempt to raise pH by
increasing respiratory rate and depth
447
The most powerful respiratory stimulant is
Rising CO2 levels
448
Normally blood PO2 affects breathing only indirectly by
Influencing peripheral chemoreceptor sensitivity to changes in PCO2
449
When arterial PO2 falls below 60 mm Hg, it becomes
Major stimulus for respiration (via peripheral chemoreceptors)
450
Changes in arterial pH resulting from ___ act indirectly through peripheral chemoreceptors
CO2 retention or metabolic factors
451
Hypothalamic controls act through ___ to modify
Limbic system; rate and depth of respiration
452
Example of hypothalamic control of respiration
Breath holding that occurs in anger or gasping with pain
453
Rise in body temperature increases
Respiratory rate
454
Direct signals from cerebral motor cortex that bypass medullary controls
Cortical controls
455
Example of cortical controls
Voluntary breath holding
456
When breath is voluntarily held, the brain stem
Reinstates breathing when blood CO2 is critical
457
Receptors in bronchioles respond to
irritants
458
When bronchiole receptors respond to irritants, they communicate with ____ via ____
Respiratory centers; Vagal nerve afferents
459
Pulmonary irritant reflexes promote reflexive constriction of
air passages
460
Repeated irritant leads to
Cough in trachea or bronchi; sneeze in nasal cavity
461
Three neural factors cause increase in ventilation as exercise begins
- psychological stimuli (anticipation of exercise)
- simultaneous cortical motor activation of skeletal muscles and respiratory centers
- excitatory centers to respiratory centers from proprioceptors in moving muscles, tendons, joints
462
Ventilation declines suddenly as exercise ends because
The three neural factors shut off
463
After exercise there is a gradual decline to baseline because of
Decline in CO2 flow after exercise ends
464
Exercise --> anaerobic respiration --> lactic acid
| Not from ____, but from
poor respiratory function; insufficient cardiac output or skeletal muscle inability to increase oxygen uptake
465
Respiratory and hematopoietic adjustments to long-term move to high altitude
Acclimitisation
466
Chemoreceptors become more responsive to PCO2 when
PO2 declines
467
Substantial decline in PO2 directly stimulates
Peripheral chemoreceptors
468
Result of acclimatisation
Minute ventilation increases and stabilises in a few days to 2-3 L/min higher than at sea level
469
At high altitude, Hb saturation and O2 levels are
Lower than normal; less O2 available
470
Decline in blood O2 stimulates kidneys to
Accelerate production of EPO
471
During acclimatisation RBC numbers increase slowly to provide
Long-term compensation
472
This is exemplified by chronic bronchitis and emphysema
Chronic obstructive pulmonary disease (COPD)
473
In COPD, there is an irreversible decrease in ability to
Force air out of lungs
474
Labored breathing
Dyspnea (characteristic of COPD)
475
Most people with COPD develop
- respiratory failure (hypoventilation)
- respiratory acidosis
- hypoxemia
476
Permanent enlargement of alveoli
- destruction of alveolar walls
- decreased lung elasticity
Emphysema
477
Decreased lung elasticity in emphysema requires
Accessory muscles necessary for breathing
478
When accessory muscles are required for respiration in emphysema, what happens?
Exhaustion from energy usage
479
Hyperinflation in emphysema leads to
Flattened diaphragm
| -->reduced ventilation efficiency
480
Damaged pulmonary capillaries in emphysema leads to
Enlarged right ventricle
481
Inhaled irritants in chronic bronchitis leads to
Chronic excessive mucus
| ->inflamed and fibrosed lower respiratory passageways
482
Inflamed and fibrosed lower respiratory passageways in chronic bronchitis leads to
Obstructed airways
- ->impaired lung ventilation and gas exchange
- ->frequent pulmonary infections
483
Strength of innate respiratory drive in COPD leads to
Different symptoms in patients
484
The different COPD symptoms in patients are
- pink puffers
| - blue bloaters
485
Characteristics of pink puffers
Thin; near-normal blood gases
486
Characteristics of blue bloaters
Stocky, hypoxic
487
COPD symptoms are treated with
- bronchodilators
- corticosteroids
- oxygen
- sometimes surgery
488
Reversible COPD is known as
Asthma
489
Characterised by coughing, dyspnea, wheezing, and chest tightness
Asthma
490
In asthma, active inflammation of airways precedes
Bronchospasms
491
Airway inflammation in asthma is immune response caused by release of
- interleukins
- production of IgE
- recruitment of inflammatory cells
492
In asthma, airways thickened with inflammatory exudate magnify
Effect of bronchospasms
493
Symptoms of this disease are fever, night sweats, weight loss, racking cough, coughing up blood
Tuberculosis
494
Treatment of tuberculosis is
12-month course of antibiotics
| -however, there are antibiotic resistant strains
495
- leading cause of cancer deaths in North America
| - 90% of all cases result of smoking
Lung cancer
496
Three most common types of lung cancer are
- adenocarcinoma
- squamous cell carcinoma
- small cell carcinoma
497
Adenocarcinoma is ___% of lung cancer cases
~40%
498
Squamous cell carcinoma is ___% of cases in lung cancer
20-40%
499
Small cell carcinoma is ___% of cases in lung cancer
~20%
500
This type of lung cancer originates in peripheral lung areas - bronchial glands, alveolar cells
Adenocarcinoma
501
This type of lung cancer is located in bronchial epithelium
Squamous cell carcinoma
502
This type of lung cancer contains lymphocyte-like cells that originate in primary bronchi and subsequently metastasise
Small cell carcinoma
503
Key to survival of lung cancer
Early detection
504
Best scan for lung cancer
Helial CT scan better than chest x-ray
505
Lung cancer
- developing breath test of gold nanoparticles
- if no metastasis --> ___
- if metastasis --> ___
- surgery to remove diseased lung tissue
| - radiation and chemotherapy
506
By ____ premature baby can breathe on its own
28 weeks
507
During fetal life, lungs are filled with fluid and blood
Bypasses lungs
508
In fetal development, gas exchange takes place via
Placenta
509
Lungs don't fully inflate until how long after birth?
2 weeks
510
Respiratory rate in newborns is
Highest; slows until adulthood
511
During development, lungs continue to mature and more alveoli are formed until
young adulthood
512
Most common lethal genetic disease in North America
Cystic fibrosis
513
In cystic fibrosis, abnormal, viscous mucus clogs passageways which leads to
Bacterial infections
| -affects lungs, pancreatic ducts, reproductive ducts
514
The cause for cystic fibrosis is
Abnormal gene for Cl- membrane channel
515
Treatments for cystic fibrosis
Mucus-dissolving drugs; manipulation to loosen mucus; antibiotics
