Ventilation

Question 1

The volume of gas inspired or expired in a single respiratory cycle

Answer 1

tidal volume

Question 2

the maximum volume of gas that can be inspired starting at the end of normal inspiration

Answer 2

inspiratory reserve volume

Question 3

the maximum volume of gas that can be expired starting from the end of a normal expiration

Answer 3

expiratory reserve volume

Question 4

the volume of gas that remains in the lungs after a maximum expiration

Answer 4

residual volume

Question 5

the total amount of gas in the lungs at the end of a maximum inspiration (the sum of all four lung volumes)

Answer 5

total lung capacity

Question 6

the maximum volume of gas that can be expired after a maximum inspiration

Answer 6

vital capacity

Question 7

the maximum amount of gas that can be inspired starting from FRC

Answer 7

inspiratory capacity

Question 8

the amount of gas in the lungs at the end of a normal expiration

Answer 8

functional residual capacity

Question 9

Three types of dead space:
anatomic dead space
alveolar dead space
physiologic dead space

Answer 9

within each tidal volume, there is a volume of gas that does not participate in gas exchange; it is nonfunctional air in terms of diffusion of O2 or CO2

Question 10

anatomic dead space

Answer 10

volume of air contained within the nose, sinuses, pharynx, larynx, and conducting airways

Question 11

alveolar dead space

Answer 11

volume of air contained within non-perfused alveoli

Question 12

physiologic dead space

Answer 12

functional measurement bc it is the sum of anatomic dead space and alveolar dead space

Question 13

Turbulant Flow

Answer 13

disorganized flow, requiring greater pressure v laminar flow

Question 14

Transitional Flow

Answer 14

mixture of turbulant and laminar flow

Question 15

Laminar flow

Answer 15

parabolic profile and smooth flow

Question 16

Ohm’s Law:
Pressure = Flow * Resistance

Answer 16

V = P/R

Question 17

Poiseullie’s Equation

Answer 17

solves for airflow

Question 18

Poiseullie’s Equation Take Home message for increasing airflow

Answer 18

increase pressure
increase radius (sympathetics)
reduce viscosity
reduce length

Question 19

Airway Resistance:
when total airway cross sectional area increases

Answer 19

airway resistance decreases

Question 20

at large lung volumes…

Answer 20

the airways widen and the resistance to airflow decreases

Question 21

at lower lung volumes…

Answer 21

the airways become narrow, and airflow resistance increases

Question 22

at very low lung volumes,

Answer 22

the small airways might close completely, especially at the bottom of the lung

Question 23

obstructive lung diseases

Answer 23

increase in airway resistance
ex: asthma, bronchitis and emphysema

Question 24

Obstructive lung diseases:
emphysema

Answer 24

inspiration is easier due to loss of elastin/collagen
expiration is harder due to airway collapse which obstructs air flow
loss of radial traction

Question 25

restrictive lung diseases

Answer 25

expansion of lung is restricted either bc of alterations in lung parenchyma or bc of diease of the pleura, the chest wall, or the neuromuscular apparatus
they are characterized by a reduced vital capacity and a small resting lung volume but the airway resistance is not increased

Question 26

pulmonary fibrosis

Answer 26

thickening of interstitial spaces with a resultant increase of radial traction, making it more difficult to expand the lungs during inspiration

Question 27

Forced Vital Capacity Maneuver

Answer 27

accomplished under maximum muscular effect to ensure maximum flow rates at all lung volumes
useful index: forced expiratory volume at one second (FEV1) which is often expressed as percentage of FVC ie FEV1/FVC
FEV1/FVC should be 80% in health person

Question 28

in obstructive diseases, such as bronchial asthma, FEV1 (forced expiratory volume at one second) is…

Answer 28

reduced much more than FVC (forced vital capacity) , giving a low FEV1/FVC

Question 29

in restrictive diseases, such as pulmonary fibrosis, both FEV1 and FVC are…

Answer 29

reduced and FEV1/FVC may be normal or even increased

Question 30

Flow-Volume Loops:
During forced expiration

Answer 30

airways narrow -> increase resistance -> reduces airflow

Question 31

Flow-Volume Loops:
During inspiration

Answer 31

airways widen -> decrease resistance -> airflow is maximal

Question 32

in obstructive lung diseases, the flow rate is __ and lung volumes are ___

Answer 32

low; increased

Question 33

in restrictive lung diseases, the flow rate and lung volumes are

Answer 33

reduced and a arched curve may be seen after maximum flow

Question 34

Control of Airway Smooth Muscle
Tone is dependent on:

Answer 34

1. autonomic NS activity
2. circulating hormones
3. inhaled particles
4. paracrine signaling

Question 35

Parasympathetic stimulation (ACh) on airway smooth muscle causes

Answer 35

bronchoconstriction

Question 36

sympathetic stimulation (Epi, NE) on airway smooth muscle causes

Answer 36

bronchodilation
B2 adrenergic receptors
inhalers used by asthmatics contain albuterol (B2 agonist)

Question 37

Control of Airway Smooth Muscle
Mast cells within the connective tissue of the lung can release

Answer 37

histamine and leukotrienes which induce constriction
they can also increase production of prostaglandins

Question 38

Control of Airway Smooth Muscle
Physical irritants and pollutants

Answer 38

activate irritant receptors in the airway submucosa
these receptors induce release of ACh from efferent parasympathetic nerves which leads to bronchoconstriction

Question 39