Lec 01: Review of Normal Structure and Function

Question 1

What are the functions of the respiratory system?

Answer 1

gas exchange, ventilation, metabolic (conversion of angiotensin I -> angiotensin II, removal of amines and metabolites), mucociliary clearance, cough, acid-base balance

Question 2

What is the spinal level of the larynx?

Answer 2

C4- C6

Question 3

What are the anatomical landmarks of the trachea?

Answer 3

below the cricoid cartilage -> carina (bifurcation into main bronchi)

Question 4

What is the spinal level of the carina

Answer 4

T5 at expiration, T6 at inspiration

Question 5

Why does aspirated material more commonly pass through the right main bronchus?

Answer 5

right main bronchus is less sharply angled from the trachea

Question 6

How many bronchopulmonary segments are there?

Answer 6

19 (9 left, 10 right)

Question 7

What are the external anatomical landmarks of the lungs anteriorly?

Answer 7

clavicle -> 8th rib or 10th rib (laterally)

Question 8

What are the external anatomical landmarks of the lungs posteriorly?

Answer 8

level of the clavicle -> T12

Question 9

What is the anatomic division of the upper and lower respiratory tracts in adults?

Answer 9

vocal cords

Question 10

What is the anatomic division of the upper and lower respiratory tracts in pediatric patients?

Answer 10

cricoid cartilage

Question 11

When do the lungs start to develop in utero?

Answer 11

4th- 5th week AOG

Question 12

What is the difference between anatomic and physiologic dead space?

Answer 12

ADS: region where gas exchange is not possible (conducting zone)
PDS: total volume that does not participate in ventilation

PDS = ADS + alveolar dead space (areas with ventilation and poor perfusion)

Question 13

What is the effect of intubation on ADS?

Answer 13

ADS is increased

Question 14

How are bronchi differentiated from bronchioles?

Answer 14

bronchi: conductive structures > 1mm, w/ glands, goblet cells and supporting cartilage plates
bronhioles: conductive structures < 1mm, glands, goblet cells and cartilage are absent, SM layer is thicker

Question 15

What are the chief sites of greatest resistance in the conducting zone?

Answer 15

medium-sized bronchi (5th-7th generations)

Question 16

What are Clara cells?

Answer 16

cuboidal, non-ciliated cells found in terminal bronchioles

Question 17

What is the Reid index?

Answer 17

ratio between the thickness of SM glands and the thickness between epithelium and cartilage (normal 0.4)

Question 18

What is the rationale of using B2-agonists as bronchodilators?

Answer 18

high concentration of B2 receptors in lower respiratory tract smooth muscles

Question 19

What are the effector inflammatory cells in COPD and asthma?

Answer 19

COPD: neutrophils, airway macrophages, cytotoxic T-cells (less responsive to glucocorticoids)

Asthma: eosinophils, mast cells

Question 20

What is the difference between laminar and turbulent airflow?

Answer 20

laminar: linear, found in small airways, relatively quiet
turbulent: characterized by eddy currents; found in large airways and at bifurcations; breath sounds are low pitched and harsh

Question 21

What is the relationship of the rate of flow to resistance based on ohm’s law?

Answer 21

the greater the rate of flow, the greater the resistance

Question 22

What is the average volume of anatomic dead space?

Answer 22

150 mL

Question 23

(T/F) Central airways contribute a greater amount of resistance compared to peripheral airways

Answer 23

T

Question 24

What is Inspiratory Capacity(IC)?

Answer 24

maximum volume that can be inhaled from normal resting end-expiratory level (3500 mL); IC = TV (500 mL)+ IRV (3000 mL)

Question 25

What is Functional Residual Capacity(FRC)?

Answer 25

volume remaining in lungs during regular breathing; FRC= IRV(1100 mL)+ RV(1200 mL)

Question 26

What is Vital Capacity(VC)?

Answer 26

maximum volume that may be exhaled following a maximum inspiration; VC = IRV(3000 mL)+ TV(500 mL)+ ERV(1100 mL)

Question 27

What is normal pulmonary capillary blood flow?

Answer 27

70 mL

Question 28

What measurements of lung volume can't be measured with a spirometer?

Answer 28

TLC, FRC, RV

Question 29

What is the composition of mucus?

Answer 29

95% water, 3% mucin, 1% lipids, <0.3% DNA

Question 30

What structures are targeted by mucolytic substances?

Answer 30

disulfide bridges

Question 31

What is the normal rate of ciliary beating?

Answer 31

12-15 bpm

Question 32

What separates the gel and sol layers in the airway?

Answer 32

surfactant

Question 33

What regulates liquid in the sol layer?

Answer 33

Na+ channel, cystic fibrosis transmembrane conductance regulator (Cl- extrusion)

Question 34

What test is used to confirm cystic fibrosis?

Answer 34

sweat test

Question 35

What is the difference between types I and II alveoli?

Answer 35

type I: extremely flattened (0.05 microns); 95% of alveolar wall type II cuboidal, secrete surfactant w/ cytosomes

Question 36

How do surfactants stabilize lungs?

Answer 36

increase in surface area reduces surface tension

Question 37

What is the difference between emphysema and fibrosis in terms of compliance?

Answer 37

emphysema: increased compliance (decreased elastic recoil) fibrosis: decreased compliance

Question 38

What is equal point pressure?

Answer 38

intrapleural pressure = airway pressure

Question 39

How does the airway remain patent during passive breathing?

Answer 39

There is a decrease in intrapleural pressure while elastic recoil remains the same. The net alveolar pressure is not matched anywhere on the airway.

Question 40

(T/F) Increasing effort during expiration (inc. intrapleural pressure) will change the location of the equal point pressure

Answer 40

F

Question 41

How does obstruction affect EPP?

Answer 41

intrapleural pressure is increased earlier and elastic recoil is decreased (lower Palv), EPP is moved upstream

Question 42

What is Fick's Law of Diffusion?

Answer 42

diffusion is directly related to surface area and inversely related to membrane thickness

Question 43

What is the effect of exercise on gas exchange?

Answer 43

exercise causes hyperventilation and shortened transit time of blood

Question 44

What is the most potent vasoconstrictor of pulmonary blood vessels?

Answer 44

lack of oxygen

Question 45

When is 90% oxygen saturation achieved?

Answer 45

60 mm Hg PaO2