Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology > Respiratory > Flashcards

Respiratory Flashcards

1
Q

functions of respiratory system

A

homeostatic regulation of blood gases: provides O2 and eliminates CO2
filtering action: protects against microbial infection
regulates blood pH
contributes to phonation + olfaction
reservoir for blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

upper airways

A

nasal cavity - nostrils
oral cavity - mouth
pharynx
larynx (vocal cords)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

lower system

A

trachea
left + right main bronchi
left + right lungs
diaphragm

thoracic wall
parietal pleura (membrane)
intrapleural fluid
visceral pleura (membrane)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

composition of structures

A

trachea + primary bronchi = C shape cartilage + smooth muscle
bronchi = plates of cartilage + smooth muscle
bronchioles = smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

conducting zone

A

pathway for gas to the respiratory zone
anatomical dead space = no alveoli + no gas exchange
~150mL

trachea
bronchi
bronchioles
terminal bronchioles = smallest airway without alveoli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

respiratory zone

A

where gas exchange occurs
contains alveoli

respiratory bronchioles (sparse alveoli)
alveolar ducts
alveolar sacs (many alveoli)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

pulmonary structures + blood vessels

A

pulmonary artery carries low-O2 blood to alveoli (500 million)
280 billion capillaries → in contact with alveoli for gas exchange
pulmonary vein carries high O2 blood to heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

alveoli

A

type I alveolar cells = simple squamous epithelium
type II alveolar cell
macrophage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

type I alveolar cells

A

involved in gas exchange
epithelial cells forming surface of alveolus
do not divide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

type II alveolar cells

A

produce surfactant
act as progenitor cells to differentiate into type I cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

respiratory membrane

A

alveolus → capillary
- alveolar fluid
- alveolar epithelium (type I + II pneumocytes)
- basement membrane of alveolar epithelium
- interstitial space
- basement membrane of capillary endothelium
- capillary endothelium

very thin = easily damaged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

respiration steps

A
  1. ventilation
  2. gas exchange in lungs
  3. gas transport
  4. gas exchange in tissues
  5. cellular respiration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q
  1. ventilation
A

breathing = exchange of air between atmosphere and alveoli by bulk flow

steps:
1. CNS sends rhythmic excitatory drive to respiratory muscles
2. respiratory muscles contract rhythmically and in organized pattern
3. changes in volume and pressures at the level of chest + lungs
4. air flows in and out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

bulk flow

A

movement due to pressure gradient → high to low
higher pressure in atmosphere compared to lungs = inspiration
F = (P alv - P atm)/R

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q
  1. gas exchange in lungs
A

exchange of O2 + CO2 between alveolar air + blood in lung capillaries by diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

diffusion

A

movement due to concentration gradient (partial pressures)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q
  1. gas transport
A

transport of O2 + CO2 through pulmonary + systemic circulation by bulk flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q
  1. gas exchange in tissues
A

exchange of O2 + CO2 between blood in tissue capillaries and cells by diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q
  1. cellular respiration
A

cellular utilization of O2 and production of CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

respiratory muscles

A

pump muscles
airway muscles
accessory muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

pump muscles

A

INS:
- diaphragm
- external intercostals
- parasternal intercostals

EXP:
- internal intercostals
- abdominals (4 = external + internal abdominal oblique, transverse + rectus abdominus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

airway muscles

A

INS:
- tongue protruders (genioglossus)
- pharyngeal + laryngeal dilators

EXP:
- pharyngeal + laryngeal constrictors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

accessory muscles

A

INS
- sternocleidomastoid
- scalene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

normal/quiet inspiration

A

diaphragm contracts → pushes abdomen down + expands thorax as air comes in
external intercostals + parasternal intercostals → pull ribs up and out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

maximal/forced inspiration

A

stronger contraction of diaphragm
recruitment of accessory muscles → further expansion of thoracic cavity
- sternocleidomastoid + scalenes move sternum up and out
- pectoralis minor elevates ribs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

normal/quiet expiration

A

no active contraction of resp muscles
relaxation of inspiratory muscles → recoil of lungs = air moves out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

maximal/forced expiration

A

abdominal muscles contract → compress organs + force diaphragm higher = push air out
internal intercostal muscles contract → pull ribs down and inward

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

spirometry

A

pulmonary function test to determine amount + rate of inspired + expired air
test lung volume + capacity
use spirometer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

tidal volume

A

Vt
volume of air moved in/out of lungs during normal breath
~500 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

inspiratory reserve volume

A

IRV
amount of air forcefully inhaled after normal inspiration
additional capacity
~3000 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

expiratory reserve volume

A

ERV
amount of air forcefully exhaled after normal exhalation
~1100 mL (smaller than IRV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

residual volume

A

RV
volume of air remaining in lungs after maximal forceful expiration
~1200 mL
prevents lungs from collapsing
cannot be measured with spirometry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

total lung capacity

A

volume of air in lungs at end of maximal inspiration
Vt + IRV + ERV + RV
5000-6000 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

inspiratory capacity

A

Vt + IRV
total capacity for inspiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

vital capacity

A

Vt + IRV + ERV
max vol of air that can be forcibly exhaled after maximal inspiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

functional residual capacity

A

ERV + RV
vol remaining in lungs at end of normal expiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

total/min ventilation

A

total amount of air moved into respiratory system per minute
= Vt x resp frequency
= 0.5L x 12 brpm
= ~6L/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

alveolar ventilation

A

amount of air moved into alveoli per minute
less than minute ventilation
depends on anatomical dead space = 0.15 L
=(Vt - dead space) x resp frequency
= (0.5 - 0.15 L) x 12 brpm
= ~4.2 L/min

dead space is constant regardless of breath size
increased depth of breathing is more effective in increasing alveolar ventilation than increasing breathing rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

FEV1

A

spirometry test:
forced expiratory volume in one second
in healthy person: should approximate vital capacity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

FVC

A

spirometry test:
forced vital capacity
total amount of air that is blown out in one breath after max inspiration as fast as possible
~ vital capacity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

FEV1/FVC ratio

A

proportion of the amount of air that is blown out in one second
normal = ~80%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

normal resp pattern

A

ratio = 83%
high FEV1 + high FVC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

obstructive resp pattern

A

FEV1 is significantly reduced, FVC is normal/reduced
= ratio <70% → reduced
difficulty exhaling all air from lungs → shortness of breath
slower exhalation of air due to damage to lungs or narrowing of airways
high air vol in lungs after full exhalation

ex. bronchial asthma, COPD, cystic fibrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

restrictive resp pattern

A

reduced vital capacity
FEV1 + FVC are reduced
ratio = 90% (almost normal)
cannot fill lungs completely (restricted from full expansion)
due to stiffness in lungs

ex. pulmonary fibrosis, neuromuscular disease, scarring of lung tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

flow

A

F = ΔP/R
proportional to pressure difference between two points
inversely proportional to resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Boyle’s Law

A

P1V1 = P2V2
for a fixed amount of an ideal gas at a fixed temp, P and V are inversely proportional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

compression of alveoli

A

↓ V = ↑ P
expiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

decompression of alveoli

A

↑ V = ↓ P
inspiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

elastic recoil

A
  • lungs have tendency to collapse
  • chest wall pulls thoracic cage outward

at equilibrium: inward elastic recoil of lungs balances outward elastic recoil of chest wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

intrapleural fluid

A

reduces friction of lungs against thoracic wall during breathing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

intrapleural pressure

A

pressure within pleural cavity
fluctuates with breathing
always sub-atmospheric (-) → opposing directions of elastic recoil of lungs + thoracic cage

if P(ip) = P(alv) → lungs would collapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

alveolar pressure

A

pressure of air inside alveoli
changes during ventilation + determines direction of air flow

dynamic - directly involved in producing air flow

when P alv = P atm, F=0

53
Q

P(alv) - P(atm)

A

governs gas exchange between lungs and atmosphere
= flow

54
Q

transpulmonary pressure

A

force responsible for keeping alveoli open
pressure gradient across alveolar wall: P(tp) = P(alv) - P(ip)

static - does not cause airflow
determines lung volume

P(tp) > 0 to maintain lungs expanded in thorax (P alv > P ip)

55
Q

inspiration

A
  1. diaphragm + inspiratory intercostals contract
  2. thorax expands
  3. P(ip) becomes more subatmospheric = ↑ P(tp)
  4. lungs expand
  5. P(alv) becomes subatmospheric
  6. air flows into alveoli
56
Q

expiration

A
  1. diaphragm + inspiratory intercostals relax
  2. chest wall recoils inward
  3. ↑ P(ip) = ↓ P(tp) - return to preinspiration value
  4. lungs recoil
  5. air in alveoli becomes compressed = P(alv) > P(atm)
  6. air flows out of lungs
57
Q

airway resistance

A

small
→ small ΔP is enough to cause airflow

58
Q

resistive forces

A
  1. inertia
  2. friction
59
Q

inertia of resp system

A

negligible

60
Q

friction

A
  1. lung tissue past itself during expansion (negligible)
  2. lung and chest wall tissue surfaces past each other
    (reduced by IPF) (negligible)
  3. frictional resistance to flow of air = 80% of total airway resistance
61
Q

laminar airflow

A

gas particles move in linear fashion
low resistance
found in small airways (distal to terminal bronchioles)

62
Q

transitional flow

A

extra energy required → produce vortices
↑ resistance
found in most of bronchial tree

63
Q

turbulent flow

A

highest resistance
large airways (trachea, larynx, pharynx)

64
Q

Poiseuille’s law

A

for laminar flow
resistance is proportional to viscosity of gas + length of tube
inversely proportional to airway radius (^4)

65
Q

R in small airways

A

each small airway has high individual resistance
terminal bronchioles aligned in parallel = lower aggregated resistance

combined → lowest R

66
Q

R in disease conditions

A

R is determined primarily by small airways → easily occluded by:
- smooth muscle contraction around airway
- edema in walls of alveoli + bronchioles
- mucous collecting in lumen of bronchioles

67
Q

lung compliance

A

measure of elastic properties of lungs
how easily lungs can expand

determined by
- elastic components of lungs + airway tissue (elastin + collagen)
- surface tension

68
Q

C(L)

A

= (ΔV)/(ΔP(tp))
change in lung volume produced by given change in P(tp)
slope of pressure-volume curve

↑ C(L) = easier to expand (at given change in P(tp))

69
Q

emphysema

A

↑ compliance
floppy lungs due to destruction of elastin in walls of alveoli = collapse of smaller airways
less elastic recoil
large changes in lung vol due to little changes in P(tp)

low O2 due to less SA for gas exchange

70
Q

pulmonary fibrosis

A

↓ compliance
collagen deposition in alveolar walls
stiff lungs
higher P(tp) changes are necessary to generate changes in lung volume

poor gas exchange causes ↓ O2

71
Q

surface tension

A

property of surface of liquid that allows it to resist external force → cohesion of molecules

gives lungs elastic recoil (makes lungs collapse)
decreases lung compliance

72
Q

alveolar surface tension

A

air entering lungs is humidified → saturated with water
water molecules cover alveolar surface
cohesion of water → create surface tension
= creates inward recoil → alveolar collapse

decreases gas volume inside alveolar = increases pressure to prevent collapse

73
Q

Laplace’s equation

A

P = (2T)/r
[T = surface tension]
at equilibrium, tendency of increased pressure to expand the alveolus balances the tendency of surface tension to collapse

the smaller the radius, the greater the pressure needed to keep alveolus inflated

74
Q

different alveolar sizes

A

smaller alveoli = greater pressure → gas movement from high to low pressure = (POTENTIALLY) small alveoli collapse into larger ones

do not collapse because of surfactant → lowers surface tension = similar pressure across alveoli

75
Q

surfactant

A

produced by type II alveolar cells
made of lipoproteins = hydrophobic + hydrophilic properties → decreases density of water molecules covering alveolar surface
reduces surface tension of alveolar fluid
= ↑ lung compliance
stabilize alveoli against collapse

76
Q

IRDS

A

infant respiratory distress syndrome
born premature = under developed lungs → immature type II alveolar cells
can’t produce enough surfactant = ↓ O2
have abnormally low lung compliance

77
Q

partial pressures of gases

A

P increases with increased motion → due to change in temperature, concentration of gas molecules

78
Q

Dalton’s Law

A

in a mixture of gases, each gas acts independently
total pressure = sum of individual pressures

79
Q

P atm

A

= P (N2) + P (O2) + P (H2O) + P (CO2)
= 760 mmHg

P (p) = % of air x P total

78% N2 → P (N2) = 593 mmHg
21% O2
1% H2O
0.04% CO2

80
Q

Fick’s Law

A

V(gas) ∝ [A/T] x D x (P1 - P2)

rate of transfer of a gas through membrane (Vgas)
- is proportional to:
A = area of diffusion
ΔP = difference in gas partial pressure between two sides
D = diffusion constant
- is inversely proportional to:
T = thickness of membrane

81
Q

D = diffusion constant

A

D ∝ (sol)/√ (MW)

sol = solubility
MW = molecular weight

82
Q

diffusion of CO2 vs O2

A

solubility: CO2 > O2
similar molecular weights

CO2 diffuses 20x more rapidly than O2

P (CO2) is higher in alveoli than atm
P (O2) is higher in atm than alveoli

83
Q

P (O2) atm > P (O2) alveoli

A
  1. loss of O2 to blood by diffusion = ↓ P (O2)
  2. mixing of inspired air with functional residual vol = ↓ P (O2)

(3.) warming + humidification of air in resp tract = ↓ P (O2)

84
Q

alveolar partial pressures

A

determined by
- P (O2) + P (CO2) in atm
- alveolar ventilation [V(A) = (V(T) - V(D)) x resp frequency]
- metabolic rate
- perfusion

85
Q

increasing alveolar ventilation

A

= ↑ O2 intake + ↑ CO2 production
= ↑ P (O2) + ↓ P (CO2)

86
Q

increasing metabolic rate

A

= ↑ O2 intake + ↑ CO2 production
= ↓ P (O2) + ↑ P (CO2)

87
Q

lung perfusion

A

amount of blood that passes through pulmonary capillary system in the lung

using O2 from alveoli + adding CO2

88
Q

systemic circulation

A

high pressure system
overcome high resistance to deliver blood to peripheral tissue

89
Q

pulmonary circulation

A

low pressure system
only deliver blood to lungs

90
Q

ventilation/perfusion ratio

A

V/Q ratio
balance between ventilation + perfusion
one of major factors affecting alveolar (+ arterial) levels of O2 + CO2

91
Q

V/Q matching

A

local perfusion decreases to match a local decrease in ventilation (+ vice versa)
↓ airflow / blood flow to region of lung
↓ P (O2) in p. blood / ↓ P (CO2) in alveoli
vasoconstriction of p. vessels / bronchoconstriction
↓ blood flow / airflow

diversion of blood flow and airflow away from local area of disease to healthy areas of the lung

92
Q

ex. bronchoconstriction causes vasoconstriction

A

blockage of airway leads to poor gas exchange in alveoli → blood flow is diverted to better ventilated alveoli to compensate

93
Q

perfused alveoli that are not ventilated

A

blocked airway → ↓P(O2) + ↑P(CO2)
decreases V/Q ratio

94
Q

ventilated alveoli that lack perfusion

A

blocked blood flow → ↑P(O2) + ↓P(CO2)
increases V/Q ratio

95
Q

O2 transport

A

arterial blood = highly oxygenated
similar partial pressures of O2 and CO2 as seen in alveoli

majority of O2 is bound to Hb → in RBC
small amount is dissolved in plasma

96
Q

CO2 transport

A

venous blood = poorly oxygenated
↓ P(O2) + ↑ P(CO2) compared to alveoli

majority of CO2 is transported as bicarbonate
some is bound to Hb = carbaminohemoglobin
small amount is dissolved in plasma

97
Q

O2 uptake in lungs

A
  • diffuses from alveoli (↑[]) to p. capillary (↓[])
  • dissolved in plasma
  • moves to RBC
  • binds with Hb
98
Q

O2 delivery to tissues

A
  • diffuses from RBC to plasma
  • diffuses into tissue = dissolved O2 in ISF
  • moves into cells
  • consumed in cell mitochondria
99
Q

oxygen-hemoglobin dissociation curve

A

x = P (O2)
- systemic venous: ↓ P(O2)
- systemic arterial: ↑ P(O2)

y = Hb saturation (%)
- ↓ as O2 dissociates from Hb

difference between Hb sat of arterial and venous = amount of O2 unloaded in tissue capillaries

100
Q

effect of DPG concentration on Hb saturation

A

DPG = metabolic waste product

no DPG = high sat (L)
added DPG = low sat (shift curve to R)

same effect seen with CO2

101
Q

effect of temperature on Hb saturation

A

high metabolism increases temperature

↑t = ↓ sat
shifts curve to R

102
Q

effect of acidity on Hb saturation

A

high metabolic activity = high acidity (low pH = high [H+])
shifts curve to R

103
Q

effect of fetal hemoglobin on Hb saturation

A

high saturation during fetal development
decreases with aging

adult Hb = shift curve to R

104
Q

CO2 uptake from tissues

A

CO2 exits cells and is dissolved in ISF → diffuses to blood
in blood = 4 pathways
1. remains in plasma as dissolved CO2
2. enters RBC and remains as dissolved CO2
3. enters RBC and binds to deoxyHb = HbCO2
4. enters RBC and reacts with H2O → carbonic acid (CA catalyst) → dissociates to HCO3- + H+

[HCO3- exits RBC; H+ increases in venous blood = ↓ pH]

105
Q

CO2 delivery to lungs

A

HbCO2 dissociates → dissolved CO2
HCO3- moves back into RBC → binds with H+ → hydrolyzed into H20 + dissolved CO2

↓[CO2] in plasma drives diffusion of dissolved CO2 from RBC into plasma
→ diffuses into alveoli

106
Q

H+ transport

A

Hb from HbO2 + H+ from H2CO3- bind together
H+ is not dissolved in RBC or plasma to maintain stable pH

Hb buffers production of H+ in peripheral tissues + capillaries

107
Q

respiratory acidosis

A

high [H+] as a result of ↑ P(CO2)

hypoventilation causes CO2 production > CO2 elimination
= ↑ P(CO2) + ↑ [H+]

108
Q

respiratory alkalosis

A

low [H+] as a result of ↓ P(CO2)

hyperventilation causes CO2 production < CO2 elimination
= ↓ P(CO2) + ↓ [H+]

109
Q

metabolic acidosis

A

high blood [H+] as a result of metabolism

change is independent of changes in P(CO2)

110
Q

metabolic alkalosis

A

low blood [H+] as a result of metabolism

change is independent of changes in P(CO2)

111
Q

neural control of breathing

A

automatic process
regulated by neuronal network in pons + medulla (brainstem)

112
Q

breathing initiation

A

in medulla
by specialized neurons (PreBotC)

113
Q

medullary respiratory centre

A

dorsal respiratory group
ventral respiratory group
Pre-Botzinger Complex: sets basal resp rate

114
Q

DRG

A

fires during inspiration
stimulates inspiratory muscles = diaphragm + external intercostals

phrenic nerve → diaphragm
intercostal nerves → external intercostals

115
Q

VRG

A

expiration
contains Pre-Botzinger Complex in upper portion = respiratory rhythm generator

intercostal nerves → internal intercostals

116
Q

pons respiratory centres

A
  • pneumotaxic centre
  • apneustic centre
    = pontine respiratory group
117
Q

PRG

A

centres help modulate activity of medullary inspiratory neurons
- termination of inspiration at appropriate time
- smooth transition between inspiration + expiration

118
Q

pneumotaxic centre

A

descending inhibition to apneustic centre + DRG

119
Q

respiratory rhythmicity centre

A

DRG + VRG
send signals to one another
= local regulation of each other

120
Q

modification of breathing

A

by:
higher structures of CNS
inputs from central + peripheral chemoreceptors
inputs from mechanoreceptors in lung + chest wall
inputs from other peripheral receptors

121
Q

inhibitory modification

A

voluntary control of breathing
Hering-Breuer reflex (stretch receptors in lungs)

122
Q

stimulatory modification

A

voluntary control of breathing
medullary chemoreceptors
carotid + aortic body chemoreceptors
proprioceptors in muscles + joints
receptors for touch, temp, + pain stimuli

123
Q

peripheral chemoreceptors

A

carotid bodies + aortic bodies
respond to changes in arterial blood:
- hypoxia = ↓ P(O2)
- metabolic acidosis = ↑ [H+]
- respiratory acidosis = ↑ P(CO2)

124
Q

central chemoreceptors

A

located in medulla
respond to changes in brain extracellular fluid:
- ↑ P(CO2) via associated changes in [H+]

125
Q

hypoxia

A

stable ventilation between 60-120 mmHg arterial P(O2)

arterial P(O2) drops below 60 → stimulation of peripheral chemoreceptors

↓ inspired P(O2) = ↓ alveolar P(O2) = ↓ arterial P(O2)
↑ firing of peripheral chemoreceptors
→ reflex via medullary respiratory neurons (activation of DRG + VRG to control activity of resp muscles centrally = ↑ resp rate + tidal vol)
↑ contraction of resp muscles = ↑ ventilation
= return of P(O2) to normal

126
Q

hypercapnia

A

stable ventilation at 40 mmHg arterial P(CO2)

arterial P(CO2) increases above 40 → stimulation of central chemoreceptors (also peripheral)

↑ P(CO2) = ↑ alveolar P(CO2) = ↑ arterial P(CO2)
↑ brain extracellular fluid P(CO2) + ↑ brain extracellular fluid [H+] = respiratory acidosis
↑ firing of central chemoreceptors
→ reflex via medullary respiratory neurons (activation of DRG + VRG to control activity of resp muscles centrally = ↑ resp rate + tidal vol)
↑ contraction of resp muscles = ↑ ventilation
= return of P(CO2) to normal

127
Q

chemoreceptors + metabolic acidosis

A

H+ stimulates peripheral chemoreceptors
(does not cross blood brain barrier)

128
Q
A

Physiology (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions