Lecture 19- Lungs

Question 1

Why is the left lung smaller than the right?

Answer 1

Because of the position of the heart

Question 2

The lungs occupy all of the thoracic cavity except for?

Answer 2

The mediastinum

Question 3

How is each lung suspended to its own pleural cavity?

Answer 3

Vascular and bronchial attachments called the lung root

Question 4

Pulmonary network

Answer 4

Carrie’s systemic blood to lungs for oxygenation

Question 5

Bronchial arteries

Answer 5

Provide systemic blood to lung tissue

Question 6

Parietal pleura

Answer 6

covers the thoracic wall, the diaphragm and around the heart between the lungs

Question 7

Visceral pleura

Answer 7

covers the external lung surface

Question 8

Pleural fluid

Answer 8

lubricates the space between the pleurae to allow friction-free movement during breathing.

Question 9

Lung compliance (lung stretch)

Answer 9

determined by distensibility of lung tissue and the surrounding thoracic cage and alveolar surface tension.

Question 10

Tidal volume

Answer 10

amount of air that moves in and out of the lungs with each breath during quiet breathing.

It averages 500 mL per breath.

Question 11

Inspiration reserve volume

Answer 11

the amount of air that can be inspired beyond the tidal volume.

Question 12

Expiratory reserve volume

Answer 12

the amount of air that can be evacuated from the lungs after tidal expiration.

Question 13

Vital capacity

Answer 13

sum of tidal volume, inspiratory reserve, and expiratory reserve volumes and is the total amount of exchangeable air.

Question 14

Residual volume

Answer 14

volume of air remaining in the lungs after maximal forced expiration.

Question 15

Total lung capacity

Answer 15

sum of all lung volumes.

Question 16

Anatomical dead space

Answer 16

volume of the conducting zone conduits, roughly 150 mL, that doesn’t contribute to gas exchange in the lungs.

Question 17

Respiratory pressures

Answer 17

A negative pressure indicates that the respiratory pressure is lower than atmospheric pressure.

Question 18

Intrapulmonary pressure

Answer 18

pressure in alveoli, which rises and falls during respiration, but always eventually equalizes with atmospheric pressure.

Question 19

Intrapleural pressure

Answer 19

pressure in the pleural cavity. It also rises and falls during respiration, but is always less than intrapulmonary pressure.

Question 20

Negative intrapleural pressure is due to?

Answer 20

The recoil force and surface tension of alveolar fluid in the lungs.

The natural tendency of the chest wall to pull outward.

Question 21

Transpulmonary pressure

Answer 21

difference between intrapulmonary and intrapleural pressure:

the greater the transpulmonary pressure, the larger the lung volume.

Question 22

Pulmonary ventilation

Answer 22

mechanical process causing gas flow into and out of the lungs according to volume changes

Question 23

Boyles law

Answer 23

states that at a constant temperature, the pressure of a gas varies inversely with its volume. Pressure changes lead to gas flow.

Question 24

What happens during quiet inspiration?

Answer 24

diaphragm and intercostal muscles contract, resulting in an increase in thoracic volume, which causes intrapulmonary pressure to drop below atmospheric pressure, and air flows into the lungs.

Question 25

What happens during forced inspiration?

Answer 25

accessory muscles of the neck and thorax contract, increasing thoracic volume beyond the increase in volume during quiet inspiration.

Question 26

Quiet expiration

Answer 26

passive process that relies mostly on elastic recoil of the lungs as the thoracic muscles relax.

Question 27

Forced expiration

Answer 27

active process relying on contraction of abdominal muscles to increase intra- abdominal pressure and depress the rib cage.

Question 28

What do non respiratory air movements cause??

Answer 28

movement of air into or out of the lungs, but are not related to breathing (coughing, sneezing, crying, laughing, hiccups, and yawning).

Question 29

Airway resistance

Answer 29

friction encountered by air in the airways; gas flow is reduced as airway resistance increases.

Insignificant for two reasons:

Upper airways very large diameter
Lower airways are smaller but very numerous

Question 30

Alveolar surface

Answer 30

Tension due to water in the alveoli acts to draw the walls of the alveoli together, presenting a force that must be overcome in order to expand the lungs.

Question 31

Surfactant

Answer 31

produced by type II alveolar cells, reduces alveolar surface tension to an optimal amount.