Ch. 23: A&P of Respiratory System

Question 1

How many lobes does each lung have?

Answer 1

Right - 3

Left - 2

Question 2

Do conducting airways serve a purpose?

Answer 2

Yes, they are a path for air to move into respiratory airways, but do not participate in gas exchange. So they are anatomical dead space that holds approx. 150mL of air or 2mL/kg

Question 3

What is the point called where the trachea divides?

Answer 3

The carina

Question 4

What reflexes happen when the carina is stimulated?

Answer 4

The cough reflex and bronchoconstriction

Question 5

Which bronchus is larger, therefore has a higher chance of aspirated material to be found there?

Answer 5

The right bronchus. The left bronchus is smaller due to the heart taking up anatomical space.

Question 6

Do respiratory airways serve a purpose?

Answer 6

YES, this is where gas exchange occurs!

Question 7

How much space do the respiratory airways hold?

Answer 7

Approx. 2.5-3L

Question 8

BONUS Why is there never 100% arterial oxygenation?

Answer 8

The bronchial circulation dumps unoxygenated blood back into the vena cava and pulmonary veins, therefore even though there can be 100% oxygenated blood right after alveolar capillaries, it always mixes with unoxygenated blood before it goes back into the left atrium.

Question 9

Define ventilation

Answer 9

The movement of air between the atmosphere and the alveoli

Question 10

Define diffusion

Answer 10

movement of oxygen and CO2 between the pulmonary capillaries and the alveoli

Question 11

Define transportation

Answer 11

movement of oxygen and CO2 in the blood to and from cells

Question 12

What is airway pressure

Answer 12

the pressure in the conducting airways

Question 13

intrapleural pressure

Answer 13

pressure in the narrow space between the visceral and parietal pleurae

Question 14

intra-alveolar pressure

Answer 14

pressure inside the alveoli

Question 15

transpulmonary pressure

Answer 15

pressure difference between the intra-alveolar pressure and the intrapleural pressure

Question 16

intrathoracic pressure

Answer 16

pressure within the entire thoracic cavity.

Question 17

What is compliance and how do we calculate it?

Answer 17

The extent to which the lungs expand. It equals:

change in lung volume (L) /
change in lung pressure (cm H2O)

Question 18

A&P changes in respiratory system with aging?

Answer 18

A-P diameter increases
Compliance is increased
Anatomical dead space increases
Residual volume increases
Muscle strength decreases
# of alveoli decreases
Alveolar elasticity is decreased
Chest wall motility is decreased
VC decreases
Blood oxygen levels decreased
Anemia is common d/t decreased hgb.

Question 19

Vt

Answer 19

Tidal volume ~500mL

Question 20

IRV

Answer 20

Inspiratory reserve volume ~3000mL

Question 21

ERV

Answer 21

Expiratory reserve volume ~1100mL

Question 22

RV

Answer 22

Residual volume ~1200mL

Question 23

VC

Answer 23

Vital Capacity ~4600mL

Question 24

TLC

Answer 24

Total Lung capacity ~5800mL

Question 25

Factors affecting alveolar-capillary gas exchange

Answer 25

Surface area available for diffusion. E.g. lung removal or disease processes such as emphysema or bronchitis Thickness of the A-C membrane. E.g. conditions such as pneumonia, interstitial lung disease, and pulmonary edema Partial pressure of alveolar gas. E.g. ascent to high altitudes where PP of O2 is reduced Solubility and molecular weight of the gas. E.g. CO2 diffuses more rapidly than O2 d/t increased solubility.

Question 26

Physiologic shunt

Answer 26

Low ventilation/perfusion ratio. When perfusion exceeds ventilation, blood passes by alveoli w/o gas exchange. Seen with pneumonia, atelectasis, tumor, or mucus plug

Question 27

Alveolar dead space

Answer 27

High ventilation/perfusion ratio. When ventilation exceed perfusion. Seen with pulmonary embolus, pulmonary infarction, cardiogenic shock, and mechanical ventilation with high Vt.

Question 28

Chemoreceptors involved in respiratory function

Answer 28

Central: sense changes in CO2 content, located near medulla and in close contact with CSF. As pH increases d/t increased CO2, the respiratory center in medulla is stimulated to increase respirations Peripheral: sense changes in O2 content, located in the aortic arch and carotids. These exert little control over normal respirations until PaO2 is below ~60 mm Hg