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Flashcards in Exam 1 physio Deck (46)
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1
Q

Compliance and emphysema

A

compliance increases

2
Q

Compliance and pulmonary fibrosis/edema/ARDS

A

compliance decreases

3
Q

Elastance forces on the lungs

A

lungs tend to collapse inward

chest wall tends to expand outward

4
Q

Pressure at functional reserve capacity

A

airway P=atmospheric P
lung collapse=chest wall expasion
in equilibrium

5
Q

Pressure at volume less than FRC

A

airway pressure (-)
forced expiration
tendancy to expand (decrease lung elastance, increase chest wall expansion forces)

6
Q

Pressure at volume more than FRC

A

airway pressure (+)
inspiration
tendancy to collapse (increase lung elastance, decrease chest wall expansion forces)

7
Q

Muscles for inspiration

A

diaphragm

external intercostals

8
Q

Intrapleural pressure and phase of respiration

A

rest: (-) intrapleural pressure
inspiration: more (-) intrapleural pressure
forced expiration: (+) intrapleural pressure

9
Q

Impact of surfactant on lungs

A

decrease collapse of small alveoli

increase lung compliance (easier inspiration)

10
Q

Pulmonary vascular resistance factors

A

inspiration increases P by expanding alveoli

forced expiration compresses vessels

11
Q

Normal Hemoglobin levels in blood and oxygen binding capacity

A

15g/dL

20.1mL oxygen/dL

12
Q

Fetal Hb and oxygen affinity

A

has increased oxygen affinity due to 2 gamma (instead of beta) subunits that decrease DPG affinity (which stabilizes T state)

13
Q

Reason for sigmoid shape of Hb dissociation curve

A

positive cooperativity of Hb

14
Q

Pressure of oxygen in pulmonary and systemic capillaries

A

pulmonary: 100mmHg (97.5% Hb sat)
systemic: 40mmHg (75% Hb sat)

15
Q

The Bohr effect

A

increased H+/temp/Pco2/BPG causes decreased Hb affinity for oxygen
allows increased release of oxygen to metabolically active tissues

16
Q

Causes of hypoxemia in pulmonary circulation

A

high altitude (decreased available oxygen)
hypoventilation
V/Q mismatch
diffusion limitation (pulmonary fibrosis/edema)

17
Q

What is hypoxemia?

A

decreased A-a gradient

18
Q

Haldane effect

A

decreased oxygen binding to Hb causes increased CO2 binding to Hb
seen in systemic capillaries

19
Q

Bicarb formation in RBC’s

A

CO2 diffuses in, converted via carbonic anhydrase
bicarb exchanged for Cl- to exit cell in systemic capillaries
reactions reversed in pulmonary capillaries (to form gaseous CO2)

20
Q

Impacts on gas diffusion across pulmonary capillaries

A

increased MW/thickness cause decreased diffusion

decreased solubility/surface area/P gradient decreases diffusion

21
Q

Pathologies and diffusion

A

emphysema decreases surface area/diffusion

fibrosis increases thickness/decreases diffusion

22
Q

Perfusion limited oxygen transport

A

oxygen saturates Hb and blood sat 1/3 way through pulmonary capillary during rest
only way to increase transport is increase perfusion rate

23
Q

Diffusion limited oxygen transport

A

during strenuous exercise/fibrosis/emphysema speed of diffusion impacts Hb sat and oxygen in blood

24
Q

Lung zones and pressures while standing

A

Zone 1: PA>Pa>Pv (compressed vessels from PA)
Zone 2: Pa>PA.Pv (blood flow dictated by Pa and PA)
Zone 3: Pa>Pv>PA (blood flow dictated by Pa and Pv, most capillaries open/high flow)

25
Q

V/Q ratios and locations in lung

A

apex: highest V/Q
base: lowest V/Q
both V and Q increase at base, but Q increases more

26
Q

Normal and ideal V/Q

A

Normal: 0.8
Ideal: 1, seen in exercise with apex vasodilation

27
Q

Meaning of V/Q ratio

A

High means wasted ventilation

Low means wasted perfusion

28
Q

V/Q and pulmonary embolism

A
Q=0
V/Q goes to infinity
physiologic dead space with no perfusion
PA of oxygen=atmospheric=150mmHg
PA of CO2=0mmHg
29
Q

V/Q and airway obstruction

A

shunt, V=0
V/Q goes to 0
PA of oxygen=40mmHg
PA of CO2=46mmHg

30
Q

Respiratory response to high altitudes (5)

A

hyperventilation (to increase oxygen)
respiratory alkalosis (breathing off CO2)
hypoxic pulmonary vasoconstriction (from low oxygen)
increased erythropoietin/RBC production
increased BPG (more oxygen release in tissues)

31
Q

Medulla and dorsal respiratory group

A

nucleus tractus solitarius
input from CN X and IX
only inspiratory neurons
synpase onto spinal cord (alpha motor neurons)

32
Q

Medulla and ventral respiratory group

A

inspiratory and expiratory neurons

Pre-Botzinger complex (generates rhythm)

33
Q

Pons and respiration

A
apneustic center (prevents inspiratory shutdown)
pneomotaxic center (inhibits inspiration)
34
Q

Slowly adapting pulmonary stretch receptors

A

myelinated
inhibits TV/overdistention of alveoli (Hering-Breur reflex)
over 1L TV, causes prolonged expiration

35
Q

Rapidly adapting irritant receptors

A

myelinated
b/t epithelial cells
irritant chemicals causes vagus stimulation
results in cough/bronchoconstriction/mucous secretion

36
Q

Pulmonary C fiber receptors

A

juxtacapillary receptors
unmyelinated
stimulated by mechano/chemo insult
causes slow shallow breathing with mucous and bronchoconstriction

37
Q

Respiratory control of Po2

A

below 60mmHg, increase ventilation

monitored by CN IX and X (bodies)

38
Q

Respiratory control of Pco2

A

arterial Pco2 increase causes increase in ventilation

very sensitive

39
Q

Metabolic acidosis impact of respirations

A

increased ventilation

blows off/removes CO2 (which is H+)

40
Q

Central control of respiration by Pco2

A

monitor H+ generated by CO2 and H2O

increased Pco2, increases ECF H+ in brain, causes increased ventilation and removal of H+

41
Q

High altitude and respiration

A

pressure decreases at higher altitude
which decreases PI02/PA02
response is increased ventilation via Po2 receptors

42
Q

Acclimatization to high altitudes

A

hyperventilation causes respiratory alkalosis
increased bicarb renally excreted
decreased pH of CSF by active transport out of CSF

43
Q

Equation for Pressure of inhaled oxygen

A

PIo2=Fi02 * (Pb-Ph20)
Fio2=0.21
Pb=760mmHg at sea level
Ph20=47mmHg

44
Q

Equation for respiratory minute ventilation

A

Ve=Vt * frequency

45
Q

Equation for alveolar minute ventilation

A

VA= f * (Vt-Vd)
Vt=tidal volume
Vd=dead space

46
Q

Reason for hysteresis in lung compliance

A

overcoming surface tension of alveoli to expand in inspiration