respiratory system L14-18 Flashcards
1
Q
respiratory functions
A
gas exchange
regulation of body pH
pathogen/ irritant protection
vocalisation
2
Q
conducting systems
A
upper respiratory tract (nasal cavity/ pharynx/ larynx)
lower respiratory tract (trachea/ bronchi/ bronchioles)
3
Q
nasal cavity function
A
debris filtration
antibacterial secretion
olfactory receptors
voice resonance
4
Q
pharynx functions
A
soft palate component for swallowing
protection from mechanical stress
5
Q
larynx function
A
sound production
prevents food/ liquids entering respiratory tract
6
Q
epithelial cells of conducting system
A
goblet
ciliated
mucociliary escalator
7
Q
goblet cell function
A
secrete mucus for continuous mucus layer
8
Q
ciliated cells
A
produce saline and sweep mucus up to pharynx
9
Q
mucociliary escalator
A
removes noxious particles from lungs
10
Q
NKCC
A
Na+ K+2Cl- symporter
11
Q
CFTR
A
cystic fibrosis transmembrane regulator channel
12
Q
mucus secretion
A
- NKCC brings Cl- into epithelial membrane
- apical anion channels allow Cl- into lumen
- ECF Na+ to lumen
- NaCl movement from ECF to lumen
13
Q
cystic fibrosis
A
deficient CFTR therefore less liquid component of mucus ^viscosity and colonisation of bacteria as mucus can’t be cleared
14
Q
c-shaped cartilage support
A
trachea patence
flexible enough for diameter change in pulmonary ventilation
15
Q
bronchi to bronchioles
A
fewer/ irregular cartilage plate
epithelium > columnar cells
^smooth muscle
16
Q
ventilation mechanics
A
pressure changes
diaphragm
respiratory muscles
17
Q
resp system at rest
A
diaphragm relaxed
intrapulm pressure = atm pressure
no air movement
18
Q
resp system on inspiration
A
thoracic volume ^
diaphragm contraction/ flattening
insp muscle contraction
19
Q
resp system on expiration
A
thoracic volume decrease
diaphragm relaxation
20
Q
Boyle’s law
A
at constant temp/ no. gas molecules, pressure and volume are inversely related
21
Q
intrapulmonary pressure
A
pressure within alveoli
22
Q
atmospheric pressure
A
pull of gravity on air
23
Q
intrapleural pressure
A
pressure in pleural cavity
doesn’t equalise w atm pressure ~4mmHg less than intrapulm and atm pressure due to elastic recoil
24
Q
pleural sac
A
2 membranes of elastic tissue/ capillaries around each lung
25
parietal pleura
outer layer of serous membrane, fused to rib cage/ diaphragm and other local structures
folds in on itself at hilum > visceral pleura
26
pleural fluid
thin fluid film within cavity
keeps lung and chest wall together
lubricant for lung movement in thorax
maintains lung inflation at rest
27
physical pulmonary factors
airway resistance
alveolar surface tension
lung compliance
28
airway resistance
forces of friction causing opposition to flow
29
airway resistance factors
length of system
airway diameter
laminar/ turbulent flow
gas viscosity
30
inflammation / mucus secretion effect on airway resistance
increases
31
alveolar surface tension
reciprocal of elasticity
32
lung compliance factors
surfactant compliance
distensibility of elastic tissue of the lung
ability of chest wall to move/ stretch in inspiration
33
alveolar surface tension
surfactant creates gas-water boundary in each alveolus
H-bonds due to partial charges vs no H-bonds in gas
34
alveolar surface tension factors
increase w decreasing diameter of alveolus
35
autonomic control of bronchial tone
bronchiole diameter controlled by smooth muscle contraction and relaxation
36
central control of bronchial tone
para innervation of airways > bronchoconstriction ^resistance
37
non-neural control of bronchial tone
symp B2 receptors on smooth muscles activated by circulating adrenergic agonists
bronchodilation and decreasing R
38
law of la Place
pressure = 2T/r
2*surface tension/ radius
39
atolectasis
collapse of alveolus due to surface tension
40
surfactant
surface active agent
contains proteins and phospholipids
polar and non-polar end
41
where's surfactant produced?
TII alveolar cells
majorly in last 10-12 gestation weeks
42
surfactant amount with alveoli size
smaller alveoli size ^surfactant
43
emphysema
alveoli loss and therefore less elastic recoil
44
fibrosis
elastic tissue replaced w scar tissue
45
spirometer function
measures lung volumes and capacities over time
46
tidal volume
volume inspired/ expired with each normal breath
47
expiratory reserve volume
maximal volume that can be expired over the inspiration of a tidal volume
48
residual volume
volume that remains in the lungs after a maximal expiration
*only whole body plethysmography can measure
49
inspiratory capacity
volume of maximal inspiration
50
functional residual capacity
vol of gas remaining in lungs after normal expiration
51
vital capacity
vol of maximal inspiration and expiration
52
total lung capacity
vol of lung after maximal inspiration
53
forced vital capacity function
assesses respiratory function
max inspiration then expiration fast
measures vital capacity and time
54
FEV1
forced expiration volume / vol expired in first second of forced expiration
55
restrictive lung disease
decreasing FVC/ normal FEV1
e.g. pulmonary fibrosis
56
obstructive lung disease
normal FVC/ decreasing FEV1
e.g. asthma/ bronchitis
57
dead space
conducting airways not contributing to gas exchange
58
anatomic dead space
volume of conducting airways
59
physiologic dead space
anatomic dead space + alveolar dead space
60
alveolar dead space
non-functioning alveoli
61
total pulmonary ventilation
ventilation rate * tidal volume
~6L/min
62
total alveolar ventilation average
~4.2L/min
63
respiration rate
12-20 breaths / min
64
alveolar gas exchange influences
PERFUSION
gas diffusion (sa/ distance > thickness/ amount of fluid)
65
gas movement factors
pressure gradient of gas
gas solubility in liquid
temperature
66
dalton law
total pressure= sum of pressures exerted by individual gases
67
Henry's law
at constant temp, pressure and solubility affects amount of gas dissolved in a liquid
68
gas movement factors
pressure
temp
solubility
69
CO2 vs O2 solubility
CO2> O2
70
pulmonary circulation
low pressure system
high flow
~5L/min
71
fick's law
flux= (permeability * conc difference)/distance
72
hyperventilation
^PO2
73
hypoventilation
decreasing PO2
hypoxemia
74
hyperbaric oxygen therapy
^PO2 exposure in chamber
treats anaemia/ severe blood loss/ decompression sickn ess
75
fibrotic lung disease
thickened alveolar membrane
76
pulmonary oedema
interstitial fluid ^ diffusion distance
^CO2 solubility in water
77
asthma
^airway resistance and decreasing alveolar ventilation
78
alveolar regional variations in inspired air factors
posture
inspiration rate/ amount
79
lung ventilation variation
base ventilated ~50% more than apex
80
gravity effects on ventilation
affects p artery hydrostatic pressure/ p vein pressure/ alveolar air pressure
81
V/Q mismatch
causes L-shunt
82
hypoxic pulmonary vasoconstriction
blood flow redirection to ventilated alveoli
^gas exchange
83
% oxygen dissolved in plasma vs Hb
plasma <2%
Hb >98%
84
PO2 at rest:
arterial blood
tissue level
100mmHg
40 mmHg
85
% O2 dissociates from HbO4
25-30%
86
PO2 at exercise:
arterial blood
tissue level
% O2 dissociates from HbO4
100mmHg
15-40mmHg
~85%
87
effect on O2 saturation curve:
^pCO2
decreasing pH
^temp
shifts right
88
T-conformations
tense (deoxygenated) > crevice w haem narrows
relax (oxygenated) > easier O2 access
89
2,3-DPG increase situations
chronic lung disease
anaemia
congestive heart failure
lower atm PO2
90
diphosphoglycerate production location
erythrocytes
91
diphosphoglycerate function
interacts w B-chains of Hb
^O2 tissue delivery
shifts dissociation curve to right
92
anaemia
O2 blood content reduction
less Hb
93
foetal Hb
efficient gas exchange between maternal/ foetal blood-streams or foetal blood stream to foetal tissue
94
foetal Hb function
takes up O2 at PO2 values at which maternal Hb is releasing it
2nd month pregnancy> 6 months old
not affected by 2,3-DPG
95
foetal Hb structure
2 alpha and 2 gamma globins
96
CO2 transport formula
enzyme used?
CO2+H2O >/< H2CO3 >/< HCO3 + H+
(carbonic anhydrase)
97
carbaminohaemoglobin production and function
CO2 + Hb
favours T conformation, ^O2 release in high CO2 areas
98
reversible binding to Hb iron of carbon monoxide
carboxyhaemoglobin
*200 * affin of Hb for O2
99
carbon monoxide functions
limits O2 carrying capacity
shifts Hb to relaxed conform
100
carbon monoxide therapy
hyperbaric O2 therapy > facilitates CO dissociation
101
nitric oxide
signalling molecule causing vasorelaxation (mediate O2 delivery)
O2-diss curve shift to left
binds oxy Hb and Fe2+ of unoxygenated Hb
102
chemoreceptor ventilation monitoring
control networks in brain stem regulate somatic motor neurones associated w respiratory muscles
103
pons
site of pontine respiratory group
affects medullary rythmicity centre
apneustic/ pneumotaxic centre
104
medulla
site of respiratory rythmicity centre
105
2 respiratory neurone types
dorsal respiratory group
ventral respiratory group
106
DRG neurone activation
automatic rythmic breathing
107
apneustic centre
dorsal location
stimulates insp neurones in medulla
108
pneumotaxic
upper
antagonises/ dominates apneustic centre
decreases inspiration
109
peripheral chemoreceptor location
aortic arch if aortic bodies
bifurcations of carotid bodies
110
peripheral chemoreceptor function
samples O2/CO2/H+ content of passing blood
aortic body info transmission via vagus nerve/ carotid bodies via glossopharyngeal nerve
respond to pCO2 changes not pO2 in blood / cerbrospinal fluid
111
CO2 level effects
^pCO2 >hyperventilation
decrease pCO2 >hypoventilation
112
metabolic acidosis
H+ ions excluded from CSF entrance by blood-brain barrier > peripheral chemoreceptor
113
herng breuer reflex
prevents lung over-inflation
stretch receptors in lung smooth muscle
114
irritant receptors
rapid adaptation to mechanical stimuli w continuous stimulation
myelinated fibres in vagus impulse
115
cough mechanism
1. irritant receptors via vagus
2. diaphragm/ external intercostal contraction
3. low p in pleural cavity
4. abdominal/expiratory muscles contract
5. trachea collapse
116
proprioception
passive movement of limbs> resp stimulation
anticipates ^O2 requirement and CO2 removal`
