Respiratory Physiology

Question 1

Where is the least airway resistance in the respiratory tract?

Answer 1

terminal bronchioles - large #s in parallel

Question 2

What is the anatomic dead space?

Answer 2

does not participate in gas exchange. warms, humidifies and filters air.

Question 3

Where does the airway smooth muscle extend to?

Answer 3

terminal bronchioles

Question 4

Where does cartilage and goblet cells extend to?

Answer 4

end of bronchi

Question 5

What is the cell type of the respiratory epithelium

Answer 5

pseudostratified ciliated columnar cells extend to beginning of terminal bronchioles, then transition to cuboidal cells.

Question 6

What makes up the respiratory zone?

Answer 6

respiratory bronchioles, alveolar ducts, and alveoli.

Question 7

Collapsing pressure of alveoli?

Answer 7

P = 2 x surface tension/radius

Question 8

What is the time frame of sufactant synthesis during fetal development?

Answer 8

Begins around 26 weeks gestation but mature levels not reached until 35 weeks gestation

Question 9

What is a more common site for aspiration of foreign body?

Answer 9

Right lung

Question 10

What is the relation of the pulmonary artery to the bronchus?

Answer 10

RALS

Right pulmonary artery is Anterior to the bronchus, Left pulmonary artery is Superior to the bronchus

Question 11

What is the equation for flow?

Answer 11

Q= P/R

Question 12

Equation for physiologic dead space?

Answer 12

V_D= V_T x (Pa_{<strong>CO</strong>2}-PE_{<strong>CO</strong>2}/Pa_{<strong>CO</strong>2})

Taco, Paco, Peco, Paco

Question 13

What is the definition of phsyiologic dead space?

Answer 13

anatomic dead space of conducting airways + functional dead space in alveoli

Question 14

What part of the lung has the largest functional dead space?

Answer 14

apex of the healthy lung

Question 15

Minute ventilation equation?

Answer 15

total volume of gas entering the lungs per minute

VE= V_Tx RR

Question 16

What is the alveolar ventilation?

Answer 16

Volume of gas perunit time that reaches the alveoli

V_A= (V_T-V_D) x RR

Question 17

Equation for compliance?

Answer 17

C=V/P

R= 8 (viscosity)xlength/πr⁴

Question 18

In normal aging, is the compliance of the lung increased or decreased?

Answer 18

increased

Question 19

What is the compliance and volume of alveoli at the apex?

Answer 19

Large volume alveoli with low compliance

Question 20

What are the characteristics of the alveoli at the base?

Answer 20

Small alveoli with high compliance; ventilation is highest in the base of the lung

Question 21

What factors favor taut form of Hb over relaxed formed?

Answer 21

Taut form in the Tissues and favors unloading of O2. Increased in Cl-, H+, CO2, 2,3-BPG, and temp favor the taut form (shift curve to the right)

Question 22

Why does fetal hemoglobin have a greater affinity for O2?

Answer 22

fetal hemoglobin has less affinity for 2,3-BPG (and 2,3-BPG normally favors unloading/taut form)

Question 23

What are the presenting symptoms of methemoglobin?

Answer 23

cyanosis and chocolate-colored blood

Question 24

How do you treat cyanide poisoning?

Answer 24

use nitrites to oxidize Hv to methemoglovine, which can bind cyanide. Use thiosulfate to bind this cyanide, forming thiocyanate, which is renally excreted.

Question 25

How can you treat methemoglobinemia?

Answer 25

methylene blue

Question 26

What is carboxyhemoglobin?

Answer 26

Form of Hb bound to CO in place of O2. Cuases decreased O2 binding capacity with a left shift in the O2-Hb dissociation curve. Decreased O2 unloading in the tissues.

Question 27

Structure of myoglobin?

Answer 27

monomeric, no cooperativity, no sigmoidal curve

Question 28

What factors cause a right shift in the oxygen-hemoglobin dissociation curve?

Answer 28

CADET face RIGHT!

CO₂, Acid, Anemia, 2,3-DPG, Elevation, Temperature increase

*right shift means that hemoglobin has less affinity for O2

Question 29

Fetal Hb and CO cause the curve to shift in which direction?

Answer 29

Left

Question 30

What is the diffusion equation for pulmonary circulation?

Answer 30

V_gas= A/T x (difference in partial pressures)

Question 31

What is perfusion limited?

Answer 31

O2 in normal health, CO2, N2O, gas equilibriates over the entire capillary. Increase diffusion by increasing blood flow.

Question 32

What is diffusion limited?

Answer 32

O2 in emphysema and fibrosis, CO. Gas DOES NOT equilibrate by the time the blood reaches the end of the capillary

Question 33

What is the alveolar gas equation?

Answer 33

PA_O2=PI_O2- Pa_CO2/R

Question 34

Where is V/Q high in the lung?

Answer 34

At the apex of the lung, “wasted ventilation” aka physiologic dead space

Question 35

Where is V/Q low in the lung?

Answer 35

at the base; “wasted perfusion” aka shunt

Question 36

Haldane effect?

Answer 36

At the lungs, Increased O2 concentration favors unloading of CO2 and loading of O2

Question 37

Bohr effect?

Answer 37

In the tissues, increased CO2 favors unloading of O2 and loading of CO2

Question 38

During exercise, what happens to the V/Q ratio?

Answer 38

Becomes more uniform from apex to base

Question 39

When is pulmonary vascular resistance the lowest?

Answer 39

at the FRC

Question 40

When is the mucociliary transport the main form of protection vs macrophages in the lungs?

Answer 40

Mucociliary– ends @ terminal bronioles

Macrophages–start @ terminal bronchioles and onward

Question 41

What value must always be the same between the systemic and pulmonary circulations?

Answer 41

blood flow per minute