Exam 1 physio

Question 1

Compliance and emphysema

Answer 1

compliance increases

Question 2

Compliance and pulmonary fibrosis/edema/ARDS

Answer 2

compliance decreases

Question 3

Elastance forces on the lungs

Answer 3

lungs tend to collapse inward

chest wall tends to expand outward

Question 4

Pressure at functional reserve capacity

Answer 4

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

Question 5

Pressure at volume less than FRC

Answer 5

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

Question 6

Pressure at volume more than FRC

Answer 6

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

Question 7

Muscles for inspiration

Answer 7

diaphragm

external intercostals

Question 8

Intrapleural pressure and phase of respiration

Answer 8

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

Question 9

Impact of surfactant on lungs

Answer 9

decrease collapse of small alveoli

increase lung compliance (easier inspiration)

Question 10

Pulmonary vascular resistance factors

Answer 10

inspiration increases P by expanding alveoli

forced expiration compresses vessels

Question 11

Normal Hemoglobin levels in blood and oxygen binding capacity

Answer 11

15g/dL

20.1mL oxygen/dL

Question 12

Fetal Hb and oxygen affinity

Answer 12

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

Question 13

Reason for sigmoid shape of Hb dissociation curve

Answer 13

positive cooperativity of Hb

Question 14

Pressure of oxygen in pulmonary and systemic capillaries

Answer 14

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

Question 15

The Bohr effect

Answer 15

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

Question 16

Causes of hypoxemia in pulmonary circulation

Answer 16

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

Question 17

What is hypoxemia?

Answer 17

decreased A-a gradient

Question 18

Haldane effect

Answer 18

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

Question 19

Bicarb formation in RBC’s

Answer 19

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)

Question 20

Impacts on gas diffusion across pulmonary capillaries

Answer 20

increased MW/thickness cause decreased diffusion

decreased solubility/surface area/P gradient decreases diffusion

Question 21

Pathologies and diffusion

Answer 21

emphysema decreases surface area/diffusion

fibrosis increases thickness/decreases diffusion

Question 22

Perfusion limited oxygen transport

Answer 22

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

Question 23

Diffusion limited oxygen transport

Answer 23

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

Question 24

Lung zones and pressures while standing

Answer 24

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)

Question 25

V/Q ratios and locations in lung

Answer 25

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

Question 26

Normal and ideal V/Q

Answer 26

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

Question 27

Meaning of V/Q ratio

Answer 27

High means wasted ventilation | Low means wasted perfusion

Question 28

V/Q and pulmonary embolism

Answer 28

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

Question 29

V/Q and airway obstruction

Answer 29

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

Question 30

Respiratory response to high altitudes (5)

Answer 30

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)

Question 31

Medulla and dorsal respiratory group

Answer 31

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

Question 32

Medulla and ventral respiratory group

Answer 32

inspiratory and expiratory neurons | Pre-Botzinger complex (generates rhythm)

Question 33

Pons and respiration

Answer 33

``` apneustic center (prevents inspiratory shutdown) pneomotaxic center (inhibits inspiration) ```

Question 34

Slowly adapting pulmonary stretch receptors

Answer 34

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

Question 35

Rapidly adapting irritant receptors

Answer 35

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

Question 36

Pulmonary C fiber receptors

Answer 36

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

Question 37

Respiratory control of Po2

Answer 37

below 60mmHg, increase ventilation | monitored by CN IX and X (bodies)

Question 38

Respiratory control of Pco2

Answer 38

arterial Pco2 increase causes increase in ventilation | very sensitive

Question 39

Metabolic acidosis impact of respirations

Answer 39

increased ventilation | blows off/removes CO2 (which is H+)

Question 40

Central control of respiration by Pco2

Answer 40

monitor H+ generated by CO2 and H2O | increased Pco2, increases ECF H+ in brain, causes increased ventilation and removal of H+

Question 41

High altitude and respiration

Answer 41

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

Question 42

Acclimatization to high altitudes

Answer 42

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

Question 43

Equation for Pressure of inhaled oxygen

Answer 43

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

Question 44

Equation for respiratory minute ventilation

Answer 44

Ve=Vt * frequency

Question 45

Equation for alveolar minute ventilation

Answer 45

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

Question 46

Reason for hysteresis in lung compliance

Answer 46

overcoming surface tension of alveoli to expand in inspiration