Gas Exchange

Question 1

alteration in gas exchange, definition

Answer 1

decrease in the exchange of O2 and CO2 between the blood and the lungs to meet cell’s oxygen needs- results in imbalance between O2 supply and demand = cellular ischemia and necrosis

Question 2

alveoli

Answer 2

the functional unit of gas exchange

Question 3

right bronchi nota bene

Answer 3

straighter, wider, more likely site of aspiration

Question 4

ventilation

Answer 4

moving gases through respiratory tract, moving air between atmosphere and alveoli- efficiency requires a V/Q match – ventilation (V) = alveoli that have air– perfusion (Q) = blood supply to alveolus

Question 5

diffusion

Answer 5

gas exchange between alveoli and blood

Question 6

perfusion

Answer 6

transport of O2 and CO2 in blood/body fluids to/from cells

Question 7

room air O2 %

Answer 7

21%

Question 8

1L nasal canula O2 %

Answer 8

24%

Question 9

respiratory center in brain

Answer 9

medulla, pons - involuntary control- controls rate, depth, rhythm

Question 10

central chemoreceptors of respiration

Answer 10

CO2 (major controller), pH

Question 11

peripheral chemoreceptors of respiration

Answer 11

responds to changes in blood O2: pO2 <70

Question 12

hypoxia

Answer 12

inadequate oxygen at cellular level

Question 13

anoxia

Answer 13

absence of oxygen

Question 14

hypoxemia

Answer 14

deficient oxygenation of the blood

Question 15

hypercapnia

Answer 15

increased concentration of CO2 in the blood

Question 16

hypocapnia

Answer 16

decreased concentration of CO2 in the blood

Question 17

O2 in blood (x2)

Answer 17

bound to hemoglobin: 97%free gas dissolved in plasma: 3%

Question 18

SaO2 + measurement method

Answer 18

saturation of O2 in arterial bloodmeasured by ABG (invasive!)

Question 19

SpO2 + measurement method

Answer 19

saturation of peripheral O2measured by pulse oximetry (non-invasive!)expected reading: >= 95%

Question 20

PaO2 + measurement method

Answer 20

partial pressure of oxygen in arterial blood (dissolved in plasma!) measured by ABGexpected reading: 80-100 mmHg (with supplement > 100)

Question 21

oxygen saturation: hemoglobin

Answer 21

each has 4 heme groups (binding to O2) –> all or nothing affinity for O2% is of ALL heme, not of ONE heme

Question 22

pulse oximetry results affected by

Answer 22

P: oor peripheral perfusion s/t cold or hypotensionE: demaL: ow cardiac outputV: asoconstrictionC: arbon monoxide poisoningalso technique/environment: shivering, high intensity lighting, dark nail polish, cold room, dirty sensor

Question 23

carbon dioxide in blood (x3)

Answer 23

1. dissolved in plasma (7%) PaCO2 = 35 to 45 mm Hg2. combined with water as carbonic acid (70%)H2O + CO2 = H2CO3 = H+ + HCO3-3. coupled with hemoglobin in RBC (23%)

Question 24

*tidal volume

Answer 24

volume of air inspired/expired with each normal breath500 ml

Question 25

*inspiratory volume

Answer 25

extra volume that can be inspired over and above tidal volume 3000 mlkey for incentive spirometry!

Question 26

expiratory reserve

Answer 26

extra volume that can be expired from forceful expiration at end of tidal expiration1100 ml

Question 27

ventilation: what affects work of breathing?

Answer 27

increased muscular work itself leads to increased O2 demand- compliance- diameter of bronchi (airway resistance)- elastic recoil of lungs- alveoli surface tension (surfactant)- chest wall (bellows!)

Question 28

compliance

Answer 28

ease with which lungs expand

Question 29

factors effecting rate of diffusion (x3)

Answer 29

1. pressure difference/concentration gradient2. distance (thickness of membrane)3. surface area (for gas exchange)

Question 30

factors effecting perfusion (x3)

Answer 30

blood flow, right? so…- movement of blood around alveoli- cardiac output- vessel patency, lumen size (vasoconstriction)

Question 31

perfusion labs

Answer 31

significant for understanding quality of bloodRBC, Hgb, HCT/PCValso know about anemia or blood loss

Question 32

• RBC typical

Answer 32

5 million/uL

Question 33

• Hemoglobin (hgb) typical

Answer 33

15 g/dL

Question 34

*Hematocrit (HCT/PCV) typical

Answer 34

45%

Question 35

V/Q mismatch: V without Q

Answer 35

ventilation without perfusion- shock or PE- wasted air (air in alveoli, no blood flow)

Question 36

V/Q mismatch: Q without V

Answer 36

perfusion without ventilation- change in ventilation volume: shallow- atelectasis, pneumonia, airway obstructionlungs compensate by pulmonary hypoxic vasoconstriction

Question 37

*pulmonary hypoxic vasoconstriction

Answer 37

redirection of blood flow around collapsed alveoli- response to V/Q match (Q no V)

Question 38

factors affecting cell respiration

Answer 38

• O2 consumption (related to cell BMR)- each organ/tissue = oxygen % according to need- availability/amount of O2 in blood - perfusion to cells- diffusion into cells (ex: edema increases distance for O2 to travel -> hypoxia)

Question 39

*increase in basal metabolic rate (BMR)… + causes

Answer 39

increases consumption of oxygen- agitation- fever & shivering- infection, sepsis, wound healing, burns- ADL, ambulation- stress- hyperthyroidism- seizures- increase work: tachypnea, tachycardia

Question 40

*hypoxia s/s

Answer 40

DECREASED MENTAL ACTIVITY OFTEN FIRST- anxiety, restlessness, confusion, irritability, apprehension, headache, impaired judgment, decreased concentration/LOCtachypnea, increased depth, dyspnea, adventitious soundstachycardia, dysrhythmiafatigue of skeletal or cardiac musclescyanosis LATE SIGNischemia and death of cells, tissues, organs

Question 41

respiratory pathogens spread

Answer 41

> 5 feet