Surface Tension/Airway Resistance

Question 1

Stimulation of adrenergic receptors by endogenous ______ and ______ causes bronchodilation via activation of β2 receptors, as do drugs such as isoproterenol.

Answer 1

epinephrine; norepinephrine

Question 2

The major site of airway resistance is found at the ______.

Answer 2

intermediate-sized bronchi

Question 3

How do emphysemics combat airway collapse?

Answer 3

they expire while pursing their lips to maintain a larger air pressure in the airways (PAW) to keep the airway open

Question 4

What are the problems created by surface tension in alveoli?

Answer 4

1. Reduced lung compliance
2. Fluid accumulation in alveoli
3. Collapse of small alveoli

Question 5

Surfactant’s efficacy increases in _____.

Answer 5

smaller alveoli

Question 6

Stimulation of adrenergic receptors by endogenous epinephrine and norepinephrine causes bronchodilation via activation of β2 receptors, as do drugs such as ______.

Answer 6

isoproterenol

Question 7

The surface tension of water is tamed by _____.

Answer 7

pulmonary surfactant

Question 8

Stimulation of ______ by endogenous epinephrine and norepinephrine causes bronchodilation via activation of β2 receptors, as do drugs such as isoproterenol.

Answer 8

adrenergic receptors

Question 9

Vagal stimulation induces ______ via release of acetylcholine.

Answer 9

bronchoconstriction

Question 10

What is pulmonary surfactant made of?

Answer 10

a mixture of lipids and proteins

Question 11

Respiratory distress syndrome (in infants) is characterized by _____.

Answer 11

a surfactant deficiency

Question 12

_______ is characterized by a surfactant deficiency.

Answer 12

Respiratory distress syndrome (in infants)

Question 13

What are the factors that control airway resistance?

Answer 13

1. lung volume
2. bronchial smooth muscle tone
3. dynamic airway collapse

Question 14

Why do emphysemics have airway collapse?

Answer 14

1. reduced lung recoil 2. expiratory muscle use 3. loss of supporting CT in the airway

Question 15

Where does surfactant come from?

Answer 15

type II alveolar surface epi cells

Question 16

In addition to acetylcholine, ______ contracts in response to histamine, several products of arachidonic acid metabolism (e.g., thromboxane A2, leukotrienes C4 and D4), and a low carbon dioxide partial pressure PCO2 in the airways.

Answer 16

bronchial smooth muscle

Question 17

Vagal stimulation induces bronchoconstriction via release of _______.

Answer 17

acetylcholine

Question 18

Surface tension is a property of the water that lines the inner surfaces of _____.

Answer 18

alveoli

Question 19

Bronchial smooth muscle is innervated by _____.

Answer 19

the vagus nerve

Question 20

In addition to acetylcholine, bronchial smooth muscle contracts in response to?

Answer 20

• histamine
• several products of arachidonic acid metabolism (e.g., thromboxane A2, leukotrienes C4 and D4)
• a low carbon dioxide partial pressure (PCO2) in the airways

Question 21

What does surfactant do?

Answer 21

• increase lung compliance
• prevent collapse of small alveoli
• prevent the accumulation of fluid inside the alveoli

Question 22

An important factor in determining compliance is _____.

Answer 22

surface tension

Question 23

For a 2-fold reduction in radius, R increases ______.

Answer 23

16-fold

Question 24

Stimulation of adrenergic receptors by endogenous epinephrine and norepinephrine causes _______ via activation of ______, as do drugs such as isoproterenol.

Answer 24

bronchodilation; β2 receptors