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Flashcards in Respiratory Physiology Deck (94)
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1
Q

What are the 2 zones to the airway tree

which zone is the site of gas exchange

A

conducting zone and repiratory zone

2
Q

what is the conducting zone

-what kind of air is in here

A

the trachea and 1st 16 generations of branching

-warm, humidify, and clean air

3
Q

what is the respiratory zone?

A

last 7 generations of branching

-site of gas exchange

4
Q

how man alveoli do the lungs contain

A

300-500 x 10^6 alveoli

5
Q

what is barometric pressure

A

760 mmHg

  • sum of partial pressure of the gases in the atmosphere
  • daltons law of PP
  • Nitrogen ~ 78%, oxygen 21%, Co2 0.04% and water ~0.5%
6
Q

what is boyle’s law?

A

at constant temperature, pressure of a gas varies inversely w/ volume
ex. P=1/V

7
Q

what is pleural pressure

A

space between visceral and parietal

8
Q

what is transpulmonary

A

alveolar minus pleural

9
Q

what are the pressures associated w/ breathing

A

pleural, alveolar. transpulmonary

10
Q

at rest, what is pleural pressure? what is alveolar pressure?

A

pleural is slightly negative

alveolar is zero

11
Q

pulmonary pressure changes during the breathing cycle:
when does air flow into lungs
when does air flow out of lungs
what is pleural pressure

A

P atm > P alveoli
P atm < P alveoli
always negative

12
Q

during inspiration, how is pressure diff?

A

pressure is more negative

less pressure in pleural space

13
Q

what is pneumothorax

what happens to the pleural space

A

air in lungs
open pleural space = to normal pressure
NOT NEGATIVE ANYMORE

14
Q

what is a tension pneumothroax

A

(piece of lung tissue can form a one way valve that allows air to enter the pleural cavity from the lung but not to escape resulting in increasing pleural pressuure w/ each breath)

  • can lead to severe shortness of breath as well as circulatory collapse
  • can be caused by CPR compressions
15
Q

what is atelectasis

-air is absorbed following what?

A

collapse of part or all of a lung by blockage of the air passage (bronchus or bronchioles)

  • air is absorbed following obstruction of bronchopulmonary segment
  • change in auscultation when tapped: resonting => dull
16
Q

what is needed for the inflation of lungs

A

negative pressure

17
Q

what is tidal volume

A

volume of air leaving the lungs during a single breath (~500mL)
-exhale

18
Q

what is total lung capacity

A

max volume of air in lungs at end of maximal inhalation (~6L)
-deepest breath you can take

19
Q

what is functional residual capacity

A

volume of air remaining in lungs at end of normal expiration
-sum of residual volume + expiratory reserve vol

20
Q

what is vital capacity

A

max vol of air that can be exhaled after a max inspiration (~4.6 L)

21
Q

what is forced vital capacity

A

expiration performed rapidly and forcefully as possible

22
Q

what is a spirometer

A

a volume recorder consisting of a double walled cylinder in which an inverted bell is immersed in water to form a seal. a pulley attaches the bell to a marker that writes on a rotating drum. when air enters the spirometere, the bell rises

23
Q

what do insects and shit use to breath

A

spiracle inside wall

-air is pumped in and out

24
Q

when is compliance the greatest?

when is compliance the lowest?

A

moderate lung volume

high/low levels

25
Q

what is lung compliance

A
lung distensibliity (malleability) 
C L = change volume / change pressure
26
Q

what is lung compliance affected by

A

lung volume,
size,
surface tension inside alveoli,
lung elasticity

27
Q

what kind of curve does compliance have? why?

A

pressure-volume curve is nonlinear

-compliance is not the same at all lung volumes

28
Q

what happens w/ low compliance

high compliance?

A

low-stiff lungs, restrictive

high-overstretched lungs, emphysema, chronic obstructive pulmonary disease

29
Q

how does alveolar surface tension contribute to compliance

what is the equation for the rel’n btwn surface tension and pressure inside alveoli

A

surface tension pulls inwardly and creates internal prssure
law of Laplace: P=2T/r
P=pressure inside alveolus, T=surface tension, r=radus

30
Q

what is neonatal respiratory distress syndrome

A

immature lungs dont have enough surfactant
(pressure will be too high inside alveoli)
-surfactant contains phospholipids and proteins
-hydrophobic end and hydrophillic end (amphipathic)

31
Q

what is work

A

force x dist
W = P x changeV
-change in lung volume (dist) x change in transpulmonary pressure (force)

32
Q

what is th energy needed for breathing at rest in healthy people
how about during heavy exercise

A

5% of total energy expenditure

20% during exercise

33
Q

waht is work required for

A

to expand lungs and overcome airway resistnace

34
Q

what moves respiratory gases across alveolar-capillary membrane?

A

diffusion

35
Q

what is the equation for partial pressure

A

PP=barometric presssure x fractional concentration of gas

36
Q

what is the PP of oxygen when it is inspired?
what is it PP of oxygen when it is in the lungs?
what is the PP of oxy in the systemic veins? (R herat)
what is the PP of CO2 in the systemic veins? (R heart)

A

160
102 (# lowers bc barometic pressure is lower)
40
46

37
Q

what happens to the fractional concentration of oxygen w/ a chnage in altitude?

what happnes to the partial pressure of oxygeN?

A

it does not change.
%age of oxy is the same at 30,000 ft and sea level

-decrease at altitude due to reduced barometric pressure

38
Q

what is gas diffusion in lungs defined by

A

fick law
-volume of gas diffusing per minute across a membrane (Vgas) is directly proportional to the membrane surface area, the diffusion coefficient of the gas (D) and the partial pressure diff of the gas (changeP) and is inversely proportional to membrane thickness (T)

39
Q

oxygen is transported to tissues in 2 forms, what are they

A

combined w/ hemoglobin (98%)

dissolved in the blood (2%)

40
Q

what is the oxyhemoglobin equilibrium curve

A

relationship btwn partial pressure oxygen, oxygen saturation, and oxy content

41
Q

hemoglobin has how many heme sites and globular protein units

A

4 oxy binding heme sites and 4 globular protein units

42
Q

how does oxygen bind to hemoglobin

A

rapidly and reversibly

43
Q

when the oxyhemoglobin curve shifts to the right (partial pressure where 50% of hemoglobin saturated), what happens

A

increase in temp, PCO2, hyopia
decrease in pH
Bohr effect

44
Q

when the oxyhemoglobin curve shits to the left what happens

A

increases affinity of hemoglobin for oxygen

-fetal hemoglobin

45
Q

how does 2,3 diphosphoglycerate (DPG) affect the hemoglobin oxygen saturation
-what is it

A

shifts to the right

glycolytic intermediate that affects hemoglobin oxygen saturation

46
Q

what does hypoxia due to lung disease or high altitude result in

A

adaptive rise in the concentrations of DPG and an improvement in the quantity of oxygen delivered to the tissues
-tissue metabolize at a higher rate

47
Q

what is the mechanism for hyopia due to lung diesease

A

in binding partially deoxygenated hemoglobin, DPG allosterically upregulates the release of the remaining oxy molec bound to the hemoglobin, thus enhancing the ability of RBCs to release oxy near tissues that need it most

changes conformation to unbind from hemoglobin more readily

48
Q

what are levels of DPG high in RBCs

A

bc they don’t have mit

-anaerobically metabolize

49
Q

what does fetal hemoglobin and myoglobin do to the oxyhemoglobin curve

A

shifts to the left

50
Q

fetal carries more what than adult hemoglobin?

A

more oxygen at a low partial pressure for oxygen

-conc. of hemoglobin is 20% higher than in adults

51
Q

what is myoglobin more abundant in

A

red muscle fibers that depend heavily on aerobic metabolism
-store oxygen in muscle

52
Q

where is haemoglobin’s saturation curve compared to myoglobin

A

to the right of myoglobin

53
Q

why does carbon dioxide readily displace oxygen from hemoglobin

A

bc of the much greater affinity it has for hemoglobin (200x that of oxygen)

54
Q

how does carbon dioxide thicken the blood

A

by stimulated production of fibrinogen

55
Q

what is the oxygen content of a pt w/ anemia who has 1/2 the normal hemoglobin content but normal partial pressure PO2

A

oxygen content that is reduced by half

56
Q

carbon dioxide is transported in 3 manners

A
  1. dissolved in plasma (10%)
  2. bound to Hb (30%)
  3. as bicarbonate in RBC cytoplasm and plasma (60%)
    - cayalyzed by action of carbonic anhydrase
57
Q

what is a chloride shift

A

antiport of bicarbonate in exchange for chloride out of the RBC into plasma
-carbon dioxide indirectly transported out of cell through this mech

58
Q

what is the haldane effect

A
  • co2 equiv of bohr effect, acting in reverse manner
  • low po2 shifts the co2 dissociation curve to the LEFT so that the blood is able to pick up more CO2 in the tissue
  • in lungs, there’s a higher PO2 so blood gives up its CO2
59
Q

what is hypoxemia

what is it cuased by

A

deficient oxygenation of the blood

  • high altitude
  • hypoventilation
  • diffusion defect, such as fibrosis
60
Q

what is hypoxia

A

deficiency of O2 reaching the tissues

  • decreased cardiac output
  • anemia
  • CO poisoning
  • cyanide poisoning
61
Q

how does cyanide poisoning decrease oxygen

A

decrease o2 utilization by blocking cytochrome C in the electron transport chain

  • stops transport of electrons to oxygen
  • prevents H ions from fueling ATP synthase to produce ATP and starves the cell of energy
62
Q

why can consumption of very high levels of cassava root lead to weakness and even paralyssi

A

CN poisoning, increased blood cyanide levels

-although its the 3rd largest source of carbs for human food in the world….

63
Q

what is the volume of pulmonary circulation? what is the amount of blood in the pulmonary capillaries?

A

volume of PC is 500 mL

70mL

64
Q

what is angiotensin-converting enzyme in?

what does it do?

A

pulmonary endothelial cells

converts angiotension 1 to angiotension 2 (which is a highly potent vasoconstrictor)

65
Q

how is pulmonary circulation in flow, pressure, and resistnace?

A

high flow
low pressure
very low resistance

66
Q

what is the mean arterial pressure? what is it in the pulmonary system?

A

90-95 mmHg

15mmHg

67
Q

what happens to pulmonary ciruclation when there is low oxygen

A

resistance is increassed

-if there is low O2 in certain parts of the lung, the blood will be shunted elsewhere

68
Q

when standing, where is flow greater

how is blood flow when supine

A

flow is greater in the base (zone 3) than at the top
(zone 1)

uniform

69
Q

how is the pressure relationship in zone 1

A

alveolar pressure >arterial pressure>venous pressure

-bc alveolar > arterial, this creates resistance to blood flow

70
Q

how is pressure relationship in zone 2

A

arterial pressure>alveolar>venous

71
Q

how is the pressure rel’n in zone 3

A

arterial pressure>venous>alveolar

72
Q

what triggers inspiratory activity in DRG and VRG?

where is it located?

A

release of inhibition of central inspiratory activity (CIA) integrator
-medullary reticular formation

73
Q

what does the dorsal respiratory group (DRG) do?

A

DRG primarily inspiration

-influences VRG by way of sensory input from the vagus and glossopharyngeal

74
Q

what does ventral respiratory group (VRG) do?

A

both inspiration and expiration

-vagus nerve keeps larynx open during expiration

75
Q

what does the pontine respiratory group do

A

turns off inspiratory neurons in the VRG to start expiration
-may integrate other autonomic functions

76
Q

what can do cerebral cortex do

A

can override everything bc of its voluntary/conscious control

77
Q

what is the medullary reticular formation in the brainstem?

where do they synapse onto?

A

a grouping of interconnected nuclei

synapse onto motor neurons C3, 4, 5

78
Q

what primarily controls ventilation

A

medulla, but w/ some input from the pons

79
Q

what are the dorsal respiratory group (DRG) neurons involved in

A

alterting the pattern for ventilation in response to the physiological needs of the body for O2 and CO2 exchange and for blood acid-base balance

80
Q

what do pulmonary stretch receptors do

A

as the lungs/airways stretch, various nerves will signal the CNS to trigger expiration
-in the smooth muscles of the airway

81
Q

what do irritant receptors do

  • where are they
  • what are they triggered by
A

contribute to reflex hypernea (rapid breathing) and broncoconstriction and may trigger the cough reflex

  • w/in epithelium of large conducting airways
  • by touch, dust, smoke
82
Q

where are j receptors
what are they stimulated by
what do they lead to

A

in alveolar walls near capillaries and in bronchi

  • stimulated by lung injury, large inflation, and acute vascular congestion
  • lead to rapid, shallow breathing
83
Q

if someone is in an acidotic state, what happen to the chemoreceptive cells in the medulla?

A

they don’t monitor acidity directly

  • H ions in the blood can’t get directly to the chemoreceptive cells
  • when acidity increases, co2 lvls also increase
84
Q

where are chemoreceptors

where are baroreceptors

A

carotid and aortic body

carotid and arotic sinus

85
Q

peripheral chemoreceptors respond to a change in…

A

PO2 not O2

ex. anemia or CO poisoning won’t have effect on response cause they dont affect PCO2

86
Q

what are aortic arch receptos innervated by

what are carotid receptors innervated by

A

vagus nerve

glossopharyngeal nerve

87
Q

what is hyperventilation stimulated by

A

metabolic acidosis through peripheral chemoreceptors

88
Q

what is cheyne-strokes breathing

A

occurs frequently during sleep, esp in lowlanders new to high altitudes
-central sleep apnea can happen (w/o breathing)

see in people w/ heart disease or people from sea lvl who relocate to high altitiudes

89
Q

what is kussmaul breathing

A

fall in blood pH in diabetic ketoacidosis that is accompanied by a characteristic increase in ventilation
-hyperventilation, quick respiratory rate

90
Q

what is agonal breathing

A
  • shallow, slow (3-4 per min), irregular inspirations followed by irregular pauses due to cerebral ischemia
  • seen shortly before death
91
Q

in adaptation to high altitudes, why is alveolar PO2 reduced?

A

due to decreased barometric prsesure which results in lower arterial PO2

92
Q

how is the ventilation rate in an adaptaion to high altitude

A

hyperventilation due to hyoxemia which will lead to respiratory alkalosis bc the starting blood isnt acidtic

93
Q

why will hb concentration increase in adaptation to high altitude

why sill 2,3,DPG levles (in RBCs) increase

why will pulmonary vascular resistnace increase

A

polycythemia (increased RBCs)

Bohr effect

bc of reduced PO2

94
Q

what is acute mountain sickness

A

related to CSF pressure differences but depends on rate of ascent.