Physiology I

Question 1

How are particles removed from the conducting airways?

Answer 1

Although large particles usually are filtered out in the nose, small particles may enter the airways, where they are captured by mucus, which is then swept upward by the rhythmic beating of the cilia.

Question 2

What receptor does sympathetic input use in conducting airways?

Answer 2

Sympathetic adrenergic neurons activate β2 receptors

Question 3

What does sympathetic input in the conducting airways result in?

Answer 3

relaxation and dilation of the smooth muscle in the conducting airways.

Question 4

What receptor does parasympathetic input use in conducting airways?

Answer 4

cholinergic neurons activate muscarinic receptors

Question 5

What does parasympathetic input in the conducting airways result in?

Answer 5

contraction and constriction of the airways

Question 6

What are some B2 agonists used in the treatment of asthma?

Answer 6

• epinephrine,
• isoproterenol,
• albuterol

Question 7

T or F. The alveolar ducts are completely lined with alveoli, and contain no cilia and little smooth muscle

Answer 7

F. The alveolar ducts are completely lined with alveoli, but they contain no cilia and little smooth muscle

the transition between conducting and respiratory airways are the respiratory bronchioles which are ciliated but also have alveoli

Question 8

The alveolar ducts terminate in _____, which also are lined with alveoli.

Answer 8

alveolar sacs

Question 9

What are the roles of Type II pneumocytes?

Answer 9

• synthesize pulmonary surfactant (necessary for reduction of surface tension of alveoli)
• regenerative capacity for the type I and type II pneumocytes.

Question 10

What is the role of alveolar macrophages?

Answer 10

these macrophages capture dust and debris (since no mucus is present in the alveoli)

Question 11

How do alveolar macrophages clear debris and dust?

Answer 11

They migrate to the bronchioles, where the beating cilia carry debris to the upper airways and the pharynx, where it can be swallowed or expectorated.

Question 12

What is bronchial circulation?

Answer 12

the blood supply to the conducting airways (which do not participate in gas exchange) and is a very small fraction of the total pulmonary blood flow.

Question 13

Static volumes of the lung are measured with a ______.

Answer 13

spirometer

Question 14

What is tidal volume (Vt)?

Answer 14

Normal volume displaced during inspiration and exspiration.

Normal tidal volume is approximately 500 mL and includes the volume of air that fills the alveoli plus the volume of air that fills the airways

Question 15

What is a normal inspiratory reserve volume? expiratory?

Answer 15

In- 3000 mL

Ex- 1200mL

Question 16

The volume of gas remaining in the lungs after a maximal forced expiration is the ______, which is approximately 1200 mL and cannot be measured by spirometry.

Answer 16

residual volume (RV)

Question 17

What is inspiratory capacity (IC)?

Answer 17

composed of the tidal volume plus the inspiratory reserve volume and is approximately 3500 mL (500 mL + 3000 mL)

Question 18

What is functional residual capacity (FRC)?

Answer 18

composed of the expiratory reserve volume (ERV) plus the residual volume, or approximately 2400 mL (1200 mL + 1200 mL).

FRC is the volume remaining in the lungs after a normal tidal volume is expired and can be thought of as the EQUILIBRIUM VOLUME of the lungs

Question 19

What is vital capacity?

Answer 19

the volume that can be expired after maximal inspiration.

Question 20

What is vital capacity composed of?

Answer 20

The vital capacity (VC) is composed of the inspiratory capacity plus the expiratory reserve volume, or approximately 4700 mL (3500 mL + 1200 mL).

Question 21

What factors influence vital capacity?

Answer 21

Its value increases with body size, male gender, and physical conditioning and decreases with age.

Question 22

What is total lung capacity (TLC)?

Answer 22

includes all of the lung volumes: It is the vital capacity plus the residual volume, or 5900 mL (4700 mL + 1200 mL).

Question 23

Because residual volume cannot be measured by spirometry, lung capacities that include the residual volume also cannot be measured by spirometry (i.e., FRC and TLC). How can FRC be measured?

Answer 23

• helium dilution method

- body plethysmograph

Question 24

What is the helium dilution method of measuring FRC?

Answer 24

the subject breathes a known amount of helium, which has been added to the spirometer. Because helium is insoluble in blood, after a few breaths the helium concentration in the lungs becomes equal to that in the spirometer, which can be measured. The amount of helium that was added to the spirometer and its concentration in the lungs are used to “back-calculate” the lung volume.

If this measurement is made after a normal tidal volume is expired, the lung volume being calculated is the FRC.

Question 25

What is the body plethysmograph of measuring FRC?

Answer 25

To measure FRC, the subject sits in a large airtight box called a plethysmograph. After expiring a normal tidal volume, the mouthpiece to the subject’s airway is closed. The subject then attempts to breathe. As the subject tries to inspire, the volume in the subject’s lungs increases and the pressure in his or her lungs decreases. Simultaneously, the volume in the box decreases, and the pressure in the box increases.

The increase in pressure in the box can be measured and, from it, the preinspiratory volume in the lungs can be calculated, which is the FRC.

Question 26

What is Dead space?

Answer 26

The volume of the airways and lungs that does not participate in gas exchange

Refers to both the anatomic dead space of the conducting airways and a functional, or physiologic, dead space

Question 27

What is the approximate volume of the conducting airways?

Answer 27

150 mL

Question 28

How much air would reach the alveoli if a tidal volume of 500mL was inspired?

Answer 28

350mL

Question 29

T or F. The first air expired is anatomic dead space air that has not undergone gas exchange.

Answer 29

T.

Question 30

What is the physiologic dead space?

Answer 30

The total volume of the lungs that does not participate in gas exchange

aka anatomic dead space of the conducting airways + a functional dead space in the alveoli.

Question 31

What is functional dead space?

Answer 31

ventilated alveoli that do not participate in gas exchange

Question 32

Why wouldn’t some alveoli participate in gas exchange?

Answer 32

a mismatch of ventilation and perfusion, or so-called ventilation/perfusion defect, in which ventilated alveoli are not perfused by pulmonary capillary blood.