page370-379

Question 1

Total lung volume (TLV) =

Answer 1

IRV + TV + ERV + RV.

Question 2

https://drive.google.com/open?id=0B8uJUY-tie8GYVhRc1B1SHJfbDg

Answer 2

https://drive.google.com/open?id=0B8uJUY-tie8GR2VhemZ0RDE0RjA

Question 3

https://drive.google.com/open?id=0B8uJUY-tie8GanZlLVN4NlB0Szg

Answer 3

https://drive.google.com/open?id=0B8uJUY-tie8GMEhmX3ZQSzFpOW8

Question 4

Active process of inspiration

Answer 4

■ Requires muscular effort.

■ Mostly diaphragm at rest.

■ Intercostals used on exertion (accessory muscles).

Question 5

Inspiratory effort causes:

Answer 5

■ ↓ intrapleural pressure.

■ ↓ alveolar pressure.

■ Pressure gradient from mouth to alveoli.

■ Gas flow down pressure gradient.

Question 6

Expiration

Answer 6

■ Passive process (usually).

■ Due to lung recoil.

Question 7

Relaxation of inspiratory muscles causes:

Answer 7

■ ↑ intrapleural pressure (intrapleural pressure becomes less negative).

■ ↑ alveolar pressure.

■ Pressure gradient from alveoli to mouth.

■ Gas flow down pressure gradient

Question 8

FUNCTIONAL RESIDUAL CAPACITY

Answer 8

■ FRC = At rest.

■ Balance between inspiratory and expiratory forces.

■ Collapsing forces = Expanding forces.

■ Muscle contraction is needed to ↑ or ↓ lung volume from FRC.

Question 9

https://drive.google.com/open?id=0B8uJUY-tie8GS1RPOG1sUmt0LWM

Answer 9

https://drive.google.com/open?id=0B8uJUY-tie8GV3RCcVlDekdXckE

Question 10

ALVEOLAR PRESSURE

Answer 10

■ Atmospheric pressure in resting position.

■ 760 mm Hg (at FRC). Palv = 0 mm Hg

Question 11

INTRAPLEURAL PRESSURE

Answer 11

■ Pressure within pleural cavity between outer surface lung and inner surface

chest cavity.

■ 756 mm Hg (at FRC) (< atomospheric pressure). Ppl = −34 mm Hg

Question 12

ALVEOLAR VENTILATION

Answer 12

■ Amount of gas that reaches the functional respiratory units (ie, alveoli) per

minute.

■ Amount of atmospheric air that can undergo gas exchange.

■ Good gauge for breathing effectiveness

VA=RR °ø (TV − dead space air volume).

Question 13

RESPIRATORY RATE

Answer 13

■ Breaths per minute.

Question 14

TIDAL VOLUME

Answer 14

■ TV = amount of air brought into/out of lungs with a normal breath.

Question 15

■ 500 mL.

■ 350 mL used for alveolar ventilation.

■ 150 mL dead space (fixed due to conducting airways).

Answer 15

tidal vol

Question 16

DEAD SPACE

Answer 16

■ VD = Volume of air not participating in gas exchange

Question 17

Anatomic dead space.

Answer 17

■ Typically 150 mL.

■ Volume of nonventilated gas in airways.

■ No gas exchange occurs within the nasal passages, pharynx, trachea,

bronchi.

Question 18

Physiologic dead space.

Answer 18

■ Due to alveoli that are ventilated but not perfused.

■ Usually insignificant, unless there is disease.

Question 19

TV °* RR = .

Answer 19

VT

Question 20

https://drive.google.com/open?id=0B8uJUY-tie8GTnV4NlJJdHExLUk

Answer 20

https://drive.google.com/open?id=0B8uJUY-tie8GZm5NRzFIY0Z2RUk

Question 21

Conducting zone airways contain mucous-secreting cells:

Answer 21

■ Goblet cells

■ Mucous cells

■ The epithelium is pseudostratified ciliated columnar.

Question 22

Respiratory zone, alveolar wall has:

Answer 22

■ Type I epithelial cells

■ Type II epithelial cells ↓ pneumocytes

■ Produce surfactant

Question 23

O2 uptake, CO2 elimination by the blood

Answer 23

■ O2 diffusion (alveolus → blood)

■ CO2 diffusion (alveolus ← blood)

Question 24

Partial pressure gradient

■xxx difference between two sides of the membrane.

■ Diffusion occurs from high to low pressure (down the gradient).

■ PAyyy > Pzzz (alveolar > pulmonary arterial); O2 diffuses from

alveoli →aaaa

■ PaCO2 xxxx > PACO2 in xxxx; CO2 diffuses from blood →alveoli

Answer 24

Partial pressure gradient

■ Pressure difference between two sides of the membrane.

■ Diffusion occurs from high to low pressure (down the gradient).

■ PACO2 > PaO2 (alveolar > pulmonary arterial); O2 diffuses from

alveoli → blood.

■ PaCO2 blood > PACO2 in alveolus; CO2 diffuses from blood →alveoli

Question 25

Gas solubility ■ Number of molecules dissolved in the liquid aa partial pressure of gas bb. ■ Solubility is an xxx property of the gas. ■ Solubility xx as partial pressure yy (Henry’s law). CO2 more zzz than O2.

Answer 25

Gas solubility ■ Number of molecules dissolved in the liquid ↑ partial pressure of gas ↑. ■ Solubility is an intrinsic property of the gas. ■ Solubility ↑ as partial pressure ↑ (Henry’s law). CO2 more soluble than O2.

Question 26

Thickness of membrane (alveolus) ■ Rate of diffusion is xxxl to the diffusion distance. ■yy diffusion as zz alveolar thickness

Answer 26

Thickness of membrane (alveolus) ■ Rate of diffusion is inversely proportional to the diffusion distance. ■ ↑ diffusion as ↓ alveolar thickness

Question 27

Alveolar surface area ■ Rate of diffusion is xxxx to surface area. ■ x surface area (eg, emphysema), y diffusion, z gas exchange

Answer 27

Alveolar surface area ■ Rate of diffusion is directly proportional to surface area. ■ ↓ surface area (eg, emphysema), ↓ diffusion, ↓ gas exchange

Question 28

Hemoglobin

Answer 28

Carries O2 from lungs to tissues. ■ Carries CO2 from tissues to lungs.

Question 29

Normally: ■xx saturated with O2 in lungs (arterial). ■ yy saturated in tissues (venous). ■ PaO2 = 40 mm Hg ■ zz million Hb molecules in each erythrocyte. ■ Synthesis begins in xxxx

Answer 29

hemoglbin

Answer 30

https://drive.google.com/open?id=0B8uJUY-tie8GVlAtM3NCSFB4bnc

Question 31

https://drive.google.com/open?id=0B8uJUY-tie8GbWJ0Z0JSbHlCb1U

Answer 31

https://drive.google.com/open?id=0B8uJUY-tie8GZkVfUmxUdG5Gb1E

Question 32

Bohr Effect

Answer 32

Curve shifts right (→) in an acidic environment (↓pH) to help unload O2 to the tissues. ■ Hb has decreased affinity for O2 when pH ↓. ■ H+’s ↑ as pH ↓. ■ The H+’s bond more actively to deoxygenated Hb than to oxyhemoglobin. ■ As CO2 ↑, pH ↓, curve shifts to the right (→).

Question 33

Haldane Effect

Answer 33

■ Oxygen tension affects the affinity of Hb for CO2. ■ High oxygen tension—lungs: ■ Hb ↑ O2 binding; ↓ affinity for CO2. ■ CO2 released in the lungs (as ↑ O2–Hb).

Question 34

Low oxygen tension—tissues:

Answer 34

■ Hb ↓ O2 binding; ↑ affinity for CO2 (binds H+, forms carbamino compounds). ■ CO2 uptake in the tissues (as ↓ O2–Hb).

Question 35

Amount of O2 in Blood

Answer 35

■ Dissolved O2 + O2 bound to Hb.

Question 36

https://drive.google.com/open?id=0B8uJUY-tie8GR083VnM2cFhaN1k

Answer 36

https://drive.google.com/open?id=0B8uJUY-tie8GNFFHR1RYTkVNWjg

Question 37

OXYGEN CONTENT

Answer 37

■ Total amount of oxygen carried in blood (PO2 + O2–Hb). ■ Determined mostly by the amount of hemoglobin and its saturation. ■ Amount of hemoglobin is affected by anemia (production, loss, or destruction). ■ The more hemoglobin in blood, the more O2 that can be carried.

Question 38

OXYGEN SATURATION

Answer 38

■ The amount of Hb saturated with O2. ■ Corresponds to O2–Hb curve. ■ Determined by: ■ PO2 (important; see table corresponding SaO2 : PO2). ■ O2 affinity of Hb altered by:

Question 39

■ Changes in Hb molecule. ■ Intrinsic (hemoglobinopathies). ■ Extrinsic (eg, changes in pH, PCO2, temperature, etc.). ■ Competition for Hb binding (eg, CO poisoning).

Answer 39

O2 saturation determined by

Question 40

NORMAL VALUES

Answer 40

■ Oxygen content (per 1 g Hb) = 1.34 mL of O2. ■ Hemoglobin concentration = ~15 g/dL. ■ Women: 12–16 g/dL. ■ Women have ↓ Hb concentrations than men ■ Men: 14–18 g/dL. ■ Infants: 14–20 g/dL. ■ Oxygen concentration = ~20 g-mL/dL (or 15 g/dL °ø 1.34 mL)—just 20.1 mL.

Question 41

OXYGEN -CARRYING CAPACITY OF BLOOD

Answer 41

Depends on: ■ Oxygenation (from lungs). ■ FiO2. ■ PaO2 (gradient). ■ Effective gas exchange (no dead space or shunt

Question 42

Hb concentration. ■ Hb avidity for oxygen. ■ CO. ■ Left shift of curve.

Answer 42

OXYGEN -CARRYING CAPACITY OF BLOOD

Question 43

Perfusion. ■ Cardiac function. ■ Patency of vessels. ■ Adequacy of forward flow

Answer 43

OXYGEN -CARRYING CAPACITY OF BLOOD

Question 44

Carbon Dioxide See Figure 13–3. ■ Carbon dioxide (CO2) is carried in blood as:

Answer 44

■ Bicarbonate in serum (most). ■ Bicarbonate in RBC. ■ Carbaminohemoglobin. ■ CO2 + NH2 group of Heme (not Fe2+ of Heme like O2 or CO). ■ Dissolved in blood (PCO2).

Question 45

CHLORIDE SHIFT

Answer 45

■ Bicarbonate carried in serum is generated within the RBC. ■ It is transported to the serum in exchange for Cl−.

Question 46

https://drive.google.com/open?id=0B8uJUY-tie8GSDBXblpPNDY3Mlk

Answer 46

https://drive.google.com/open?id=0B8uJUY-tie8GT3dJdGpNNVUwWFE

Question 47

https://drive.google.com/open?id=0B8uJUY-tie8GZ09FNDhtMkdudmc

Answer 47

https://drive.google.com/open?id=0B8uJUY-tie8GWWYwSEVBZ2lxNTQ

Question 48

Hypoxemia

Answer 48

■ Low oxygen level in blood (PO2 \<80). ■ Causes of hypoxemia: ■ ↓ FiO2 ■ Hypoventilation ■ V/Q mismatch ■ Shunt ■ Diffusion limitation

Question 49

HYPOXIC VASOCONSTRICTION

Answer 49

■ Mechanism to minimize V/Q mismatch.

Question 50

Shunt (air cannot get into alveolus).

Answer 50

■ Peanut occluding bronchiole (child). ■ Atelectasis.

Question 51

Blood perfuses past the alveolus.

Answer 51

Blood perfuses past the alveolus. ■ No/minimal gas exchange occurs. ■ Response is vasoconstriction of the pulmonary vasculature in that region. ■ ↓ amount of blood going to nonventilated segment of lung.

Question 52

If this vasoconstriction secondary to hypoxia exists for long enough,

Answer 52

If this vasoconstriction secondary to hypoxia exists for long enough, ■ Get permanent secondary changes to the pulmonary vasculature. ■ Pulmonary hypertension. ■ Only place in body to constrict, not dilate

Question 53

Hypercarbia

Answer 53

■ ↑ CO2 in blood. ■ Occurs because of either or both of the following: ■ ↑ CO2 production. ■ ↓ VA (alveolar ventilation)—hypoventilation. ■ Compensation: hyperventilation. ■ Headache. ■ Confusion. ■ Coma.

Question 54

Hyperventilation ■ ↑ rate and depth of breathing exceeding requirement for O2 delivery and CO2 removal

Answer 54

■ Stimulated by: ■ ↓ PO2 in normal circumstances (non-COPD). ■ Chemoreceptor stimulation (↑CO2, ↑H+, ↓PO2). ■ Effect on brain—emotional situations, anxiety.

Question 55

Hyperventilation Results in:

Answer 55

■ ↓ CO2: hypocapnia (hypocarbia). ■ Respiratory alkalosis (pH ↑). ■ ↑cerebrovascular resistance. ■ ↓ cerebral blood flow. ■ ↑PO2 (and arterial oxygen concentration

Question 56

https://drive.google.com/open?id=0B8uJUY-tie8GSi1UR3h0dDNLb1k

Answer 56

https://drive.google.com/open?id=0B8uJUY-tie8GLXZqUlFDNEFvSHM

Question 57

SYMPTOMS OF HYPERVENTILATION

Answer 57

■ Related to ↓ cerebral blood flow. ■ Example: anxiety → ↑ventilation → ↓ CO2 → ↓ cerebral blood flow → neurologic symptoms: ■ Faintness/dizziness. ■ Blurred vision. ■ Also experience sensation of: ■ Suffocation. ■ Chest tightness.

Question 58

Terminate hyperventilation attack must:.

Answer 58

■ ↑ PCO2. ■ Breathing in and out of a plastic bag. ■ Inhale 5% CO2 mixture

Question 59

Respiratory Drive

Answer 59

■ Based on arterial PCO2, specifically H+. ■ The H+ (derived from CO2) that acts at central chemoreceptors (medulla).

Question 60

PATHWAY

Answer 60

■ As ↑ PCO2 → CO2 diffuses from cerebral blood vessels into CSF → carbonic acid (H2CO3) is formed → dissociates into bicarbonate (HCO3 −) and protons (H+s) → these protons (H+s) stimulate the central chemoreceptors→↑ ventilation. ■ CO2 can diffuse from the blood vessels into CSF across the BBB because it is nonpolar.

Question 61

↑RESPIRATORY DRIVE

Answer 61

↑RESPIRATORY DRIVE ■ Central chemoreceptors (medulla) ■ ↑ PCO2 (as its byproduct, H+, in CSF or brain interstitial fluid sensed in medulla). ■ Peripheral chemoreceptors (carotid or aortic bodies) ■ ↑ H+ (in blood or brain interstitial fluid). ■ ↓ PO2 (in blood)(\<60 mm Hg

Question 62

FUNCTION OF RESPIRATORY REGULATION

Answer 62

■ Keep alveolar PCO2 stable (prevent hypercarbia or hypocarbia). ■ Buffer acid–base changes. ■ Prevent hypoxemia (↑ PO2 when it falls).

Question 63

https://drive.google.com/open?id=0B8uJUY-tie8GNHNHc1Rkay1qUnM

Answer 63

https://drive.google.com/open?id=0B8uJUY-tie8GVGRFbWRzaHZVOEE

Question 64

https://drive.google.com/open?id=0B8uJUY-tie8GTEF1V19TbVU4cjQ

Answer 64

https://drive.google.com/open?id=0B8uJUY-tie8GdnFUQjZSS05ueUE