Block 4.6 -- Respiratory Structure and Function

Question 1

What is the function of the conduction zone?

Answer 1

Gets air to the respiratory zone

Question 2

What is the function of the respiratory zone?

Answer 2

Site of gas exchange

Question 3

Dead space represents the volume of air that does not participate in what?

Answer 3

Gas exchange

Question 4

Mouth to terminal bronchioles is what zone? Does it participate in gas exchange?

Answer 4

Conducting zone, no

Question 5

The respiratory bronchioles to alveolar sacs is what zone? Does it participate in gas exchange?

Answer 5

Respiratory zone, yes

Question 6

Anatomical dead space accounts for reduction of plasma what from atmospheric to alveolar?

Answer 6

Plasma O2

Question 7

Humidification decreases what?

Answer 7

Plasma O2

Question 8

Airways connect lungs to external environment and warm and humidify and filter what air?

Answer 8

Inspired

Question 9

Mucus traps small particles and cilia move it away from where?

Answer 9

The lungs

Question 10

As respiratory airways progress, does total surface area increase or decrease?

Answer 10

Increase

Question 11

In the respiratory airways, parasympathetic leads to bronchoconstriction or bronchodilation? Does this increase or decrease airway resistance and smooth muscle contraction?

Answer 11

Bronchoconstriction, increases both

Question 12

In the respiratory airways, sympathetic (epinephrine) leads to bronchoconstriction or bronchodilation? Does this increase or decrease airway resistance and smooth muscle contraction?

Answer 12

Bronchodilation, decreases smooth muscle contraction and can decrease airway resistance

Question 13

Bronchodilation is mediated by beta-2 adrenergic receptors (G-protein coupled receptor). The activation of these decreases MLCK activity and increases what levels?

Answer 13

cAMP levels

Question 14

Each cluster of alveoli is surrounded by elastic fibers and a network of what, with up to several thousand per alveolus

Answer 14

Capillaries

Question 15

At basal heart rates, red blood cells spend about 0.75 seconds in the pulmonary capillaries. This is 2-3 times the time needed to completely equilibrate with what gases?

Answer 15

Alveolar gases

Question 16

What are air sacs where gas exchange occurs?

Answer 16

Alveoli

Question 17

What forms clusters at the ends of respiratory bronchioles?

Answer 17

Alveoli

Question 18

Each what is one-cell layer thick?

Answer 18

Alveolus

Question 19

Which type of alveolar epithelial cells have 95-97% of total surface area where gas exchange occurs?

Answer 19

Type 1 alveolar cells

Question 20

Which type of alveolar epithelial cells secrete pulmonary surfactant and reabsorb water and what, preventing fluid buildup?

Answer 20

Reabsorb water and sodium

Question 21

What contains the heart, trachea, esophagus, and thymus within the central mediastinum, with the lungs filling the rest?

Answer 21

Thoracic cavity

Question 22

Which pleura lines the thoracic wall?

Answer 22

Parietal pleura

Question 23

Which pleura covers the lungs?

Answer 23

Visceral pleura

Question 24

The parietal and visceral pleura are normally pushed together, with a fluid-filled space between called what?

Answer 24

Intrapleural cavity (pleural cavity)

Question 25

What is a dome-shaped skeletal muscle of respiration that separates the thoracic and abdominal cavities?

Answer 25

Diaphragm

Question 26

Pressure differences between the two ends of the conducting zone occur due to changing what volumes?

Answer 26

Changing lung volumes

Question 27

What is pressure of the air outside the body?

Answer 27

Atmospheric pressure

Question 28

What is pressure in the lungs?

Answer 28

Intrapulmonary or intra-alveolar pressure

Question 29

What is pressure within the intrapleural space that contains a thin layer of fluid to serve as a lubricant?

Answer 29

Intrapleural pressure

Question 30

When intrapulmonary pressure is lower than atmospheric pressure, is it inspiration (inhalation) or expiration (exhalation)? Is the pressure generally -3 or 3 mmHg?

Answer 30

Inspiration (inhalation), -3 mmHg

Question 31

When intrapulmonary pressure is greater than atmospheric pressure, is it inspiration (inhalation) or expiration (exhalation)? Is the pressure generally -3 or 3 mmHg?

Answer 31

Expiration (exhalation), +3 mmHg

Question 32

Pressure below that of the atmosphere is called negative or what pressure?

Answer 32

Subatmospheric

Question 33

At rest, the diaphragm is what?

Answer 33

Relaxed

Question 34

For air to flow in, intrapulmonary pressure must be above or below atmospheric pressure?

Answer 34

Below

Question 35

Thoracic and lung volume increases for inspiration, causing intrapulmonary pressure to decrease, causing what to occur?

Answer 35

Air to flow in

Question 36

The diaphragm drops down and flattens during contraction or relaxation?

Answer 36

Contraction

Question 37

Thoracic and lung volume decreases for expiration, causing intrapulmonary pressure to increase, causing what to occur?

Answer 37

Air to flow out

Question 38

The diaphragm and chest wall muscles between the ribs relax, with the thoracic volume increasing or decreasing?

Answer 38

Thoracic volume decreases

Question 39

The pressure within an enclosed space is inversely proportional to its what?

Answer 39

Volume

Question 40

Increasing lung volume during inspiration decreases intrapulmonary pressure to below the atmospheric pressure, causing air to what?

Answer 40

Air to flow in

Question 41

Decreasing lung volume during expiration increases intrapulmonary pressure to above the atmospheric pressure, causing air to what?

Answer 41

Air to flow out

Question 42

Is intrapleural pressure higher or lower than both the atmospheric pressure and intrapulmonary pressure in inspiration and expiration?

Answer 42

Lower than both

Question 43

Transpulmonary pressure is the difference between what two pressures?

Answer 43

Intrapulmonary pressure and intrapleural pressure

Question 44

What keeps lungs against thoracic wall, allowing lungs to expand during inspiration?

Answer 44

Intrapleural pressure

Question 45

If the sealed pleural cavity is opened to the atmosphere, air flows in? What then occurs?

Answer 45

Pneumothorax (air in thorax)

Question 46

Lungs expand when what?

Answer 46

Stretched

Question 47

What is defined as change in lung volume per change in transpulmonary pressure, or change in volume divided by change in pressure?

Answer 47

Compliance

Question 48

Is high or low compliance easily stretchable?

Answer 48

High compliance

Question 49

What allows return to initial size after being stretched (recoil)?

Answer 49

Elasticity

Question 50

Due to the lungs being 'stuck' to the thoracic wall, are they always under elastic tension?

Answer 50

Yes

Question 51

Tension increases during inspiration and is reduced by what during expiration?

Answer 51

Elastic recoil

Question 52

Pressure is directly proportional to what and inversely proportional to radius of alveolus?

Answer 52

Surface tension

Question 53

The force holding fluid molecules together at an air-fluid interface (H-bonds) is what?

Answer 53

Surface tension

Question 54

Small alveoli would be at greater risk of collapse without what?

Answer 54

Surfactant

Question 55

Pressure = 2T(Surface Tension) over what?

Answer 55

Radius

Question 56

What secretes surfactant?

Answer 56

Type 2 alveolar cells

Question 57

Surfactant consists of hydrophobic protein and what?

Answer 57

Phospholipids

Question 58

Surfactant reduces the surface tension at air:water interface by eliminating the attractive forces between what?

Answer 58

Water molecules

Question 59

Surfactant becomes more or less concentrated as alveoli get smaller during expiration?

Answer 59

More concentrated

Question 60

Surfactant prevents collapse and allows a residual volume of air to remain where?

Answer 60

In the lungs

Question 61

What is the amount of air expired or inspired during quiet breathing?

Answer 61

Tidal volume

Question 62

What is tidal volume x respiratory rate (~6 L/min)?

Answer 62

Tidal Minute Volume

Question 63

What is expiratory and inspiratory reserve volume + tidal volume?

Answer 63

Vital Capacity