Chapter 22 Respiratory System Flashcards
(95 cards)
1
Q
pulmonary ventilation
A
-movement of air into and out of the lungs
2
Q
external respiration
A
-O2 and CO2 exchange between the lungs and the blood
3
Q
transport
A
-O2 and CO2 in the blood
4
Q
internal respiration
A
-O2 and CO2 exchange between systemic blood vessels and tissues
5
Q
anatomy of respiratory system
A
- nose
- nasal cavity
- pharynx
- larynx
- trachea
- bronchi
- lungs
- alveoli
6
Q
the nose
A
- provides an airway for respiration
- moistens and warms the entering air
- filters and cleans inspired air
- serves as a resonating chamber for speech
- houses olfactory receptors (humans- 5 million scent receptors, bloodhounds have 300 million)
7
Q
nasal cavity
A
- filter, heat, and moisten air
- vestibule- nasal cavity superior to the nostrils -> superior, middle, and inferior nasal conchae
- olfactory mucosa- smell receptors
- respiratory mucosa:
- goblet cells- contain lysozyme and defensins
- cilia- moves contaminated mucus
- warms inspired air
8
Q
pharynx (throat): nasopharynx
A
- air passage
- uvula prevents food from entering cavity
- Eustachian tube
9
Q
pharynx (throat): oropharynx
A
-pseudostratified columnar protects against friction and chemical trauma
10
Q
pharynx (throat): laryngopharynx
A
-lies posterior to epilottis
11
Q
larynx (voice box)
A
- attaches to the hyoid bone and opens into the laryngopharynx
- vocal ligaments and vestibular folds
- provides a patent airway
- routes air and food into proper channels
- voice production
- 9 cartilages of the larynx:
- thyroid cartilage (adams apple)
- ring shaped cricoid cartilage
- 3 paired cartilages
- epiglottis
12
Q
vocal ligaments of larynx
A
-true vocal cords
13
Q
vestibular folds of the larynx
A
- false vocal cords
- outermost folds
14
Q
vocal cord surgery
A
-use of laser to stop bleeding and remove polyp
15
Q
speech
A
-intermittent release of expired air while opening and closing the glottis
16
Q
pitch
A
- determined by the length and tension of the vocal cords
- faster vibration- higher pitch (boys in puberty)
17
Q
loudness
A
-depends upon the force of air
18
Q
sound
A
-shaped into language by muscles of the pharynx, tongue, soft palate, and lips
19
Q
larynx
A
- vocal folds may act as a sphincter to prevent air passage
- ex. valsava’s maneuver:
- glottis closes to prevent exhalation
- abdominal muscles contract
- intra-abdominal pressure rises
- helps to empty the rectum or stabilize the trunk during heavy lifting
20
Q
trachea
A
- windpipe
- from the larynx to primary bronchioles
- wall composed of 3 layers:
- mucosa
- submucosa
- adventitia- outermost layer
21
Q
conducting zone structures
A
- trachea -> right and left main (primary bronchi
- main bronchus enters the hilum of one lung
- each main bronchus branches into lobar (secondary) bronchi (3 right, 2 left)
- each lobar bronchus supplies one lobe
- lobar (secondary bronchus ->
- segmental (tertiary) bronchus ->
- bronchioles ->
- terminal bronchioles are the smallest, less than .5 mm diameter
22
Q
left lung
A
- smaller due to heart
- right bronchus more vertical
23
Q
respiratory zone
A
-respiratory bronchioles, alveolar ducts, alveolar sacs (clusters of alveoli)
24
Q
alveoli features
A
- surrounded by fine elastic fibers
- open alveolar pores- equalizes air pressure throughout lung
- house alveolar macrophages- keeps surfaces sterile
25
smoking
- tobacco
- nicotine- stimulates increased HR
- carbon monoxide- blocks O2 transport in HB
- tar- cancer causing
- smoking paralyzes cilia
- without cilia inhaled particles cling to wall or enter lung
26
lungs
- 2 lungs
- left has 2 lobes
- right has 3 lobes
- apex- superior tip just under clavicle (top)
- base- concave inferior portion above diaphragm
- hilum- vessels
27
occasionally food or liquids will go down the wrong pipe, initiating a cough reflex. Which structural barrier has been breached in this happens
- laryngopharynx
- uvula
- epiglottis*
- glottis
28
epiglottis
-elastic cartilage- covers the laryngeal inlet during swallowing
29
glottis
-opening between the vocal cords
30
the respiratory membrane is composed of ____
- the alveolar sacs and pulmonary arteries
- the alveolar membrane, the capillary wall, and their fused basement membrane*
- the alveolar macrophages and elastic fibers
- the cells found between the alveolar pores
31
men tend to have deeper voices than women because their vocal cords ______
- have a wider opening
- art shorter and narrower
- have a narrower opening
- are longer and thicker*
32
blood supply
- pulmonary circulation- low pressure, high volume
- pulmonary AA- blood from heart to be oxygenated
- pulmonary VV- freshly oxygenated blood
- bronchial circulation- oxygenated blood to lung -> tissue
33
pleurae
- thin, double layered serosa
- parietal pleura- thoracic wall
- visceral pleura- on lung tissue
- pleural space- pleural fluid for lubrication
- allows friction free movement during breathing
34
pressure relationship in the thoracic cavity
- 1. atmospheric pressure (Patm)- pressure exerted by the air surronding the body
- 760 mm Hg at sea level
- 2. respiratory pressure: negative respiratory pressure is less than Patm
- positive respiratory pressure is greater than Patm
- zero respiratory pressure = Patm
35
intrapulmonary pressure
- 1. intrapulmonary (intra-alveolar) pressure (Ppul)- pressure in the alveoli
- always eventually equalizes with Patm
- 2. intrapleural pressure (Pip): pressure in the pleural cavity
- always a negative pressure (
36
pressure relationships
- if Pip (intrapleural)=Ppul (intralveolar) the lungs collapse -> pneumothorax
- Ppul - Pip = transpulmonary pressure
- keeps the airways open
- the greater the transpulmonary pressure, the larger the lungs
37
pulmonary vetilation
- inspiration and expiration
- mechanical processes that depend on volume changes in the thoracic cavity
- volume changes -> pressure changes
- pressure changes -> gases flow to equalize pressure
38
boyles law
- the relationship between the pressure and volume of a gas
- pressure (P) varies inversely with volume (V)
- P1V1 = P2V2
39
inspiration
- an active process
- inspiratory muscles contract
- thoracic volume increases
- lungs are stretched and intrapulmonary volume increases
- intrapulmonary pressure drops (to -1mm Hg)
- air flows into the lungs, down its pressure gradient, until Ppul = Patm
40
inspiration sequence of events
- 1. inspiratory muscles contract (diaphragm descends; rib cage rises)
- 2. thoracic cavity volume increases
- 3. lungs are stretched; intrapulmonary volume increases
- 4. intrapulmonary pressure drops (to -1 mmHg)
- 5. air (gases) flows into lungs down its pressure gradient until intrapulmonary pressure is 0 (equal to atmospheric pressure)
41
3 cells of alveoli
- alveoli type 1 cells- gas exchange
- type 2 alveolar cells- surfactant
- macrophage- keep the alveoli sterile
- RBC and alveolus exchange gas -> capillaries are by the membrane for exchange
42
blood air barrier
- air and blood never mix
- membranes are close to each other
- O2 and CO2 cross the membrane into their respective systems
43
expiration
- quiet expiration is normally a passive process inspiratory muscles relax
- thoracic cavity volume decreases
- elastic lungs recoil and intrapulmonary volume decreases
- Ppul rises (to +1 mmHg)
- air flows out of the lungs down its pressure gradient until Ppul = 0
- note- forced expiration is an active process- it uses abdominal and internal intercostal muscles
44
expiration sequence of events
- 1. inspiratory muscles relax (diaphragm rises; rib cage descends due to recoil of costal cartilages)
- 2. thoracic cavity volume decreases
- 3. elastic lungs recoil passively; intrapulmonary volume decreases
- 4. intrapulmonary pressure rises (to +1 mmHg)
- air (gases flows out of lungs down its pressure gradient until intrapulmonary pressure is 0
45
physical factors influencing pulmonary ventilation
- inspiratory muscles work to overcome three factors that hinder air passage and pulmonary ventilation
- 1. airway resistance
- 2. alveolar surface tension
- 3. lung compliance
46
airway resistance
- friction- resistance to gas flow
- the relationship between flow (F), pressure (P), and resistance (R) is:
- F = (change in P) / R
- change in P is the pressure gradient between the atmosphere and the alveoli (2 mmHg or less during normal quiet breathing)
- gas flow changes inversely with resistance (straw)
- resistance is usually insignificant because of large airway diameters in the first part of the conducting zone and progressive branching of airways as they get smaller, increasing the total cross sectional area
- resistance disappears at the terminal bronchioles where diffusion drives gas movement
- as airway resistance rises breathing becomes more strenuous
- severely constricting or obstruction of bronchioles can occur during acute asthma attack and stop ventilation
- epinephrine (SNS) dilates bronchioles and reduces air resistance
47
alveoli surface area
- film over alveoli contains surfactant which reduces cohesiveness of water and prevents collapse of alveoli
- respiratory disease syndrome (RSD)
48
lung compliance
- change in lung volume that occurs with a given change in transpulmonary pressure
- normally high due to:
- distensibility of the lung tissue
- alveolar surface tension
- diminished by:
- nonelastic scar tissue (fibrosis)
- reduced production of surfactant
- decreased flexibility of the thoracic cage baloon
49
the pressure in the alveoli is known as _______
- intrapulmonary pressure*
- intrapleural pressure
- transpulmonary pressure
- atmospheric pressure
50
if transpulmonary pressure were to suddenly decrease to 0, predict the response by the lungs
- the lungs would not recoil, and air would remain trapped in them
- the lungs would adhere to the parietal pleura and would crumple like an accordion*
- the lungs would immediately collapse
- the lungs would remain unchanged
51
surfactant helps to prevent the alveoli from collapsing by...
- humidifying the air before it enters
- warming the air before it enters
- interfering with the cohesiveness of water molecules, thereby reducing the surface tension of alveolar fluid*
- protecting the surface of alveoli from dehydration and other environmental variations
52
air moves into the lungs during inspiration due to the force of ____
- the diaphragm*
- the abdominal muscles- also an acceptable answer
- atmospheric pressure
- the external intercostal muscles
53
respiratory volumes
- used to assess a persons respiratory status
- inspiratory reserve volume (IRV)- amount of air that can be forcefully inhaled
- expiratory reserve volume (ERV)- amount of air that can be forcefully exhaled
- residual volume (RV)- amount of air remaining in the lungs after a forceful exhale
- inspiratory capacity (IC) -tidal volume and inspiratory reserve
- functional residual capacity (FRC)- expiratory reserve and residual volume
- vital capacity (VC)- volume of exchangeable air and everything but residual volume
54
tidal volume (TV)
-air exchange between normal breathing
55
inspiratory reserve volume (IRV)
-amount of air that can be forcefully inhaled
56
expiratory reserve volume (ERV)
-amount of air that can be forcefully exhaled
57
residual volume (RV)
-amount of air remaining in the lungs after a forceful exhale
58
inspiratory capacity (IC)
-tidal volume and inspiratory reserve
59
functional residual capacity (FRC)
-expiratory reserve and residual volume
60
vital capacity (VC)
- volume of exchangeable air
| - everything but residual volume
61
total lung capacity
- TLC
| - all of the volume combined
62
dead space
- some inspired air never contributes to gas exchange
- anatomical dead space- conducting zones
- alveolar dead space- alveoli that are collapsed or obstructed
63
pulmonary function tests
-PFTs can determine obstructive lung disease from restrictive lung disease
64
non respiratory air movements
- most result from reflex action
| - ex. cough, sneeze, crying, laughing, hiccups, and yawns
65
gas exchange between blood, lungs, and tissues
- external respiration
- internal respiration
- to understand the above processes, first consider:
- physical properties of gases
- composition of alveolar gas
66
external respiration
- exchange of O2 and CO2 across the respiratory membrane
- influenced by:
- 1. partial pressure gradients and gas solubilities
- 2. ventilation-perfusion coupling
- 3. structural characteristics of the respiratory membrane
67
partial pressures
- pressure exerted by a gas
- directly proportional to the percentage of that gas in the mixture
- at higher altitudes, partial pressure declines in direct proportion to decrease in atm pressure
- the pressure of each gas in a mixture
68
partial pressure gradients and gas solubilities
- parial pressure gradient for O2 in the lungs is steep
- venous blood Po2= 40 mmHg
- alveolar Po2 = 104 mmHg
- O2 partial pressure reach equilibrium of 104 mmHg in about .25s, about 1/3 time a RBC is in a pulmonary capillary
- partial pressure gradient for OC2 in the lungs is less steep:
- venous blood Pco2 = 45 mmHg
- alveolar Pco2 = 40 mmHg
69
ventilation-perfusion coupling
- ventilation- amount of gas reaching the alveoli
- perfusion- blood flow reaching the alveoli
- ventilation and perfusion must be matched (coupled) for efficient gas exchange
- changes in Po2 in the alveoli cause changes in the diameters of the arterioles
- where alveolar O2 is high -> arterioles dilate
- where alveolar O2 is low -> arterioles constrict (moves blood to other areas)
- changes in Pco2 in the alveoli causes changes in the diameters of the BRONCHIOLES
- where alveolar CO2 is high -> bronchioles dilate
- where alveolar CO2 is low -> bronchioles constrict
70
thickness and surface area of the respiratory membrane
- respiratory membranes have large surface area
- edema/fluid causes increased thickening of membrane (CHF)
- reduction in surface area with emphysema (destruction of alveoli)
71
internal respiration
- capillary gas exchange in body tissues
- partial pressures and diffusion gradients are reversed compared to external respiration
- Po2 in tissue is always lower than in system arterial blood
- Po2 of venous blood is 40mmHg and Pco2 is 45 mmHg
72
inverse relationship
-between pressure and volume
73
respiratory transport - O2
- molecular O2 is carried in the blood
- 1.5% dissolved in plasma (poorly soluble in water)
- 98.5% loosely bound to each Fe of hemoglobin (Hb) in RBCs
- 4 O2 per Hb
- oxyhemoglobin = combination of oxygen + hemoglobin
- saturated vs partial saturated
74
O2 and hemoglobin
- rate of loading and unloading of O2 is regulated by:
- PO2
- temperature
- Blood pH
- Pco2
- oxygen hemoglobin disassociation curve
75
oxygen-hemoglobin dissociation curve
- only 20-25% of bound O2 is unloaded during one systemic circulation
- Hemoglobin is almost completely saturated at a Po2 of 70 mm Hg
- Further increases in Po2 produce only small increases in O2 binding
- 1. In arterial blood:
- Po2 = 100 mm Hg
- Hb is 98% saturated
2. In venous blood:
- Po2 = 40 mm Hg
- Hb is 75% saturated
76
other factors influencing hemoglobin saturation
- increases in temperature, H+, and Pco2 enhance O2 unloading
- occur in systemic capillaries
- shift the O2 hemoglobin dissociation curve to the right (Bohr effect)
- decreases in these factors shift the curve to the left
77
factors that increase release of O2 by hemoglobin
- as cells metabolize glucose:
- PCO2 and H+ increase in blood
- declining pH (acidic) enhances O2 unloading (bohr effect -> shift to right)
- heat production increases- increasing temperature causes HB to unload more O2 to working muscles
78
CO2 transport
- CO2 is transported in the blood in 3 forms
- 1. plasma (7 to 10%)
- 2. bound to globin of hemoglobin (20%)
- 3. bicarbonate ions (HCO3-) 70% in plasma
- CO2 + H2O -> H2CO3 -> H+ + HCO3
79
haldane effect
- the amount of CO2 transported is affected by the PO2
- at tissues- the lower the PO2 and O2 saturation the more CO2 the blood can carry
- at lungs- uptake of O2 facilitates release of CO2
80
influence of CO2 on blood pH
- carbonic acid-bicarbonate buffer system:
- CO2 + H2O -> H2CO2 -> H+ HCO3
- if H+ concentration in blood rises, excess H+ is removed by combining with HCO3-
- if H+ concentration begins to drop, H2CO3 dissociates, releasing H+
- changes in RR or depth can change blood pH
- short shallow breaths- increase CO2 -> lower pH
- deep breaths -> reduce CO2
- can use this to adjust blood pH during:
- increased lactic acid during exercise
- fatty acid metabolism (ketone bodies) in uncontrolled DM
81
obstructive pulmonary disease
- more and more dead space
- nonusable air
- cannot fully exhale
- asthma
- COPD
82
restrictive lung disease
- lungs have issues expanding
- fibrotic
- cystic fibrosis
83
even the most forceful exhalation leaves air in the lungs; this is called the ____ and is needed to ____
- tidal volume; acquire adequate O2
- vital capacity; remove adequate CO2
- functional residual capacity; keep alveoli patent
- residual volume; keep alveoli patent
84
if there is an increase in alveolar CO2, the body will adjust by
-dilating the arterioles in the lung
constricting the arterioles in the lung
-dilating the bronchioles in the lungs*
-constricting the bronchioles in the lungs
85
an increase in temperature or CO2 will cause
- a shift in the oxygen-hemoglobin dissociation curve to the left
- a shift in the curve to the right
- an increase in O2 unloading
- A and D
- B and C
86
pontine respiration center
- influence and modify activity of the VRG
| - smooth out transition between inspiration and expiration and vice versa
87
medullary respiration centers
- DRG- dorsal- integrates input from baroreceptors (peripheral stretch) and chemoreceptors
- VRG- ventral- sets RR at 12-15 BPM:
- inspiratory neurons excite
- expiratory neurons inhibit
88
chemical factors influencing PCO2
- if PCO2 levels rise (Hypercapnia), CO2 accumulates in the brain
- elevated H+ stimulates the central chemoreceptors of the brain stem
- chemoreceptors synapse with the respiratory regulatory centers, increasing the depth and rate of breathing
89
depth and rate of breathing
- hyperventilation- increased depth and rate of breathing that exceeds the bodys need to remove CO2
- causes CO2 levels to decline (hypocapnia)
- may cause cerebral vasoconstriction and cerebral ischemia
90
chemical factors influence of PO2
- peripheral chemoreceptors in the aortic and carotid bodies are O2 sensors
- substantial drops in arterial PO2 (to 60mmHg) must occur in order to stimulate increased ventilation
91
summary of chemical factors
- rising CO2 levels are the most powerful respiratory stimulant
- normally blood PO2 affects breathing only indirectly influencing peripheral chemoreceptor sensitivity to changes in PCO2
92
influence of higher brain centers
- hypothalamic controls act through the limbic system to modify rate and depth of respiration
- ex. breath holding that occurs in anger or gasping with pain
- a rise in body temperature acts to increase respiratory rate (reverse occurs- jump in cold water)
- cortical controls can bypass medullary controls -> Ex. voluntary breath holding
93
inflation reflex: hering-breuer reflex
- stretch receptors in the pleurae and airways are stimulated by lung inflation
- these receptors send message to respiratory center (vagus NN) to end inhalation
- protective response
94
COPD
- chronic bronchitis
| - emphysema
95
restrictive lung disease
- ALS/MD
- scoliosis
- obesity
- sarcoidosis
