II: Respiratory System Unit

Question 1

Pleura formed by

Answer 1

Parietal and visceral pleura

Question 2

Parietal pleura composition

Answer 2

Fibrous membrane

Question 3

With what is the parietal membrane in contact with

Answer 3

Thoracic cage

Question 4

With what is the visceral layer in contact with

Answer 4

Lungs

Question 5

Barometric pressure definition

Answer 5

Pressure of the atmosphere (the air)

Question 6

At the end of respiration both barometric and alveolar pressures =

Answer 6

0

Question 7

What causes a difference of -1 between alveolar and barometric pressure

Answer 7

The retraction of the diaphragm

Question 8

What causes air to move to the interior of lungs

Answer 8

The difference of -1 between alveolar and barometric pressure

Question 9

At the end of inspiration, barometric and alveolar P are

Answer 9

Equal

Question 10

What causes air to move out of the lung

Answer 10

During expiration, the diaphragm relaxes to Palveolar&raquo_space; Pbarometric

Question 11

Process of air coming in and out (TODO)

Answer 11

Before inhalation (P barometric and P alveolar = 0)

During inhalation the diaphragm contracts so Palveolar decreases. There is a difference of -1 between alveolar and barometric pressure

At the end of inhalation Palveolar = Pbarometric because P alveolar is 0 again

Diaphragm stops retracting, thoracic cage decreases in volume, Palveolar»Pbarometric so air comes out of lungs

Question 12

Why does inspiration occur

Answer 12

Due to the differences in barometric and alveolar pressure

Question 13

What facilitates inspiration

Answer 13

Respiration muscles

Question 14

What is hysteresis

Answer 14

Differences in volumes during inspiration and expiration, at the same pressure

Question 15

What is closing capacity, CC

Answer 15

Volume at which the smallest airways collapse

Question 16

Does the lung ever run out of air

Answer 16

No, starting point is never 0 due to the closing capacity

Question 17

The intrapleural pressure is always

Answer 17

NEGATIVE

Question 18

What keeps the lungs in the rib cage

Answer 18

The negative intrapleural pressure

Question 19

Ppleural at upper poles =

Answer 19

-10cmH2O

Question 20

Ppleural at lower poles

Answer 20

-2cmH2O

Question 21

Greater distensibility in

Answer 21

Upper alveoli because they are larger

Question 22

Greater expanding capacity in

Answer 22

Lower alveoli so they participate more in ventilation

Question 23

Lung compliance definition

Answer 23

Change in volume in lungs at a given pressure

Question 24

Average lung compliance in lung

Answer 24

200mL/cmH2O

Question 25

The greatest distensibility found at

Answer 25

Intermediate zones

Question 26

Pulmonary emphysema cause

Answer 26

Intralveolar septa are ruptures

Question 27

Consequence of pulmonary emphysema

Answer 27

More air enters the lungs at low pressures No effective gas exchange due to low pressures Decrease in O2 --> dyspnea More distensibility (due to decreased resistance) --> more compliance

Question 28

What increases distensibility in pulmonary emphysema

Answer 28

The lack of resistance

Question 29

Pulmonary fibrosis cause

Answer 29

Septa are thickenes

Question 30

Consequences of pulmonary fibrosis

Answer 30

Greater resistance to be overcome | Less distensibility = less compliance

Question 31

What is surface tension

Answer 31

The energy exerted on a surface to maintain its SA/unit area

Question 32

What cancels surface tension in alveolis

Answer 32

Surfactant produced by type II pneumocytes

Question 33

How do pneumocytes work

Answer 33

They exert forces in all directions to forces cancel

Question 34

Blockage of airways leading to alveoli will cause

Answer 34

Alveolar collapse

Question 35

LaPlace's law:

Answer 35

Gradient pressure = 2y/r ``` y = surface tension r = alveolar radius ```

Question 36

Pressure required to keep alveoli expanded is greater in small or large alveoli

Answer 36

Small

Question 37

Why is there exchange between small and large alveolus

Answer 37

Because ∆P is greater in small alveolus

Question 38

Types of exchange between small and large alveolus

Answer 38

Equal exchange: 2 alveolus = in size so air flowing in and out is equal Non-equitational exchange: more air exiting airways + entering in small alveolus

Question 39

Compositino of surfactant

Answer 39

(90% lipids and 10% H2O)

Question 40

Functions of surfactant

Answer 40

Decrease ST Increase stability Prevent pulmonary edema

Question 41

Production of surfactant according to the size of alveolus

Answer 41

Large alveolus produce SMALL surfactant --> decrease in size | Small alveolus produce LARGE surfactant --> maintain size

Question 42

Respiratory distress syndrome in newborns occurs due to

Answer 42

Lack of surfactant --> stiffness and little distensibility in lungs