Exam 2: Pulm Physio

Question 1

(pulm volumes graph)

Answer 1

(pulm volumes graph)

Question 2

Gas-exchange airways include:

Answer 2

Respiratory bronchioles
Alveolar ducts
Alveoli

Question 3

Alveolar cells:

Answer 3

Type 1: gas exchange (super thin)

Type 2: surfactant production

Question 4

Airway generation at which gas exchange begins:

Answer 4

~16

Question 5

What is the respiratory exchange ratio?

Answer 5

The ratio of O2 in via food and CO2 out via metabolism

Question 6

Protective benefits of faster exhalation than inhalation & mechanism by which this is accomplished:

Answer 6

Encourages elimination of dust & mucus/debris

Airways open during inhalation (slower gas velocity) and vice versa during exhalation

Question 7

Why are spinal cord injury patients prone to pneumonia?

Answer 7

Can often breath, but not cough

Question 8

ANS effects on airways:

Answer 8

Epinephrine opens airways

Question 9

Function of alvolar pores:

Answer 9

Allow for collateral airflow if other alveoli ducts get clogged

Question 10

Effects of interstitial thickening:

Answer 10

Harder for O2 to diffuse through

CO2 is slightly polar and can pass through more easily

Question 11

Only thing between pleura:

Answer 11

Pleural fluid

Question 12

Function of scalene muscles in breathing:

Answer 12

Lift the ribs

Question 13

Function of trapezius in breathing:

Answer 13

None

Question 14

Formula for alveolar surface tension:

Answer 14

P * R / wall thickness

Question 15

Compliance is:

Answer 15

Ability to accept change in volume

Question 16

Function of surfactant:

Answer 16

↓ surface tension of water

Question 17

Relative pleural pressure during inspiration/end inspiration/expiration/end expiration:

Answer 17

Slightly negative at rest; more negative during inspiration; less negative (or even positive) during expiration

Question 18

Under normal conditions, ventilation rate is driven by:

Answer 18

CO2

Question 19

Under hypoxic conditions, ventilation is driven by:

Answer 19

Arterial CO2 tension (sensed by carotid body)

Question 20

PO2, PCO2 in inspired air:

Answer 20

PO2: 159mmHg
PCO2: 0.3mmHg

Question 21

PO2, PCO2, PH2O in alveolar air:

Answer 21

PO2: 104mmHg
PCO2: 40mmHg

Question 22

PO2, PCO2 in pulmonary vein:

Answer 22

PO2: 100mmHg
PCO2: 40mmHg

Question 23

PO2, PCO2 at tissues:

Answer 23

PO2: 40mmHg
PCO2: 46mmHg

Question 24

PO2, PCO2 in pulmonary artery:

Answer 24

PO2: 40mmHg
PCO2: 46mmHg

Question 25

Fetal hgb has ____ affinity to O2 than normal hgb:

Answer 25

Higher; needs to “steal” O2 from the maternal blood in the placenta

Question 26

Factors that increase oxyhemoglobin affinity:

Answer 26

Alkalosis (↑pH) or ↓ PCO2
↓ temperature
↓ 2,3 DPG
Carboxyhemoglobin/methemoglobin
Abnormal hgb

These are associated with decreased metabolism and thus decreased O2 need (so INCREASED affinity)

Question 27

Factors that decrease oxyhemoglobin affinity:

Answer 27

Acidosis (↓ pH) or ↑ PCO2
↑ temperature
↑ 2,3 DPG - can be from high altitude
Abnormal hgb

These are associated with increased metabolism and stress, so decreased affinity/increased O2 delivery is a good thing

Left shift for Lounging around
Right shift for Running from a bear

Question 28

Define P50 and how it is associated with the oxyhemoglobin dissociation curve:

Answer 28

The PaO2 at which hgb is 50% saturated; normally 26.6mmHg

Decreased affinity = high P50
Increased affinity = low P50

Question 29

CO2 is ____x more soluble than O2:

Answer 29

30x

Question 30

Most abundant protein in blood:

Answer 30

Hgb

Question 31

90% of CO2 in the blood is found in this form:

Answer 31

Bound to hgb (the amino end, not the O2 binding site)

Question 32

O2 content of blood equation:

Answer 32

1.34 * Hgb * SpO2 (+ 0.0003 * PO2)

Question 33

Pulmonary response to hypoxia:

Answer 33

Vasoconstriction (unique to lungs) - shunts blood to better-ventilated regions

Question 34

Hypoxia affecting the entire lungs can cause:

Answer 34

Pulmonary HTN

Question 35

Pulmonary response to acidemia:

Answer 35

Pulmonary artery constriction

Question 36

Describe high V/Q:

Answer 36

Impaired perfusion to alveolus means alveolar dead space and less oxygenated blood rejoining the system

Question 37

Describe low V/Q or shunt:

Answer 37

Blocked ventilation (low V/Q) or collapsed alveolus (shunt) means no oxygenation of blood in that region

Question 38

Describe lung zone I:

Answer 38

Hyperinflated alveoli, crushed capillaries
PA > Pa > PV
No blood flow

Question 39

Describe lung zone II:

Answer 39

Pa > PA > PV
Blood flow occurs
Alveolar pressure compresses venules

Question 40

Describe lung zone III:

Answer 40

Sad alveoli, engorged capillary
Pa > PV & PA
Blood flow fluctuates depending on PA and PV

Question 41

Ideal FEV1/FVC:

Answer 41

> 90%

Question 42

Spirometry measures:

Answer 42

Inspiratory reserve volume
Expiratory reserve volume
Vital capacity

Question 43

Changes in the pulmonary system with aging:

Answer 43

Loss of elastic recoil
Stiffening of chest wall (↓ compliance)
Alterations in gas exchange
↑ in flow resistance
↓ vital capacity due to ↑ residual volume

Question 44

Point in fetal development at which cuboidal epithelium in alveoli turns into type 1 cells:

Answer 44

28 weeks

Type II cells not working; these preemies need surfactant