Pulmonary Ventilation

Question 1

Components of conductive zone

Answer 1

Bronchi, bronchioles, and terminal bronchioles

Question 2

Components of respiratory zone

Answer 2

Respiratory bronchioles, alveolar ducts, alveoli

Question 3

Role of conductive zone

Answer 3

Bulk movements of air, No respiratory function but does play a defensive role

Question 4

Role of respiratory zone

Answer 4

Site for gas exchange, functional unit is acinus: terminal bronchiole, respiratory bronchioles, alveolar duct, and alveoli (alveolar sac) and their circulation

Question 5

What is equal at all points in the respiratory system? (because it is a closed system)

Answer 5

air velocity * total airway area / time

Question 6

What makes up the respiratory membrane?

Answer 6

capillary endothelium, basement membrane of capillary endothelium, (extracellular fluid with connective tissue fibers), basement membrane of alveolar epithelium, alveolar epithelium

Question 7

Distance from alveolus to capillary lumen

Answer 7

less than or equal to .5 micrometers

Question 8

Defensive functions of the respiratory system

Answer 8

Conditioning of inspired air (nose to pharynx)
(Humidification and warming, prevents dessiccation of respiratory surface/infection)
Filtration (Particles greater than 10 micrometers removed by hairs in the nose, 2-5 micrometer particles settle out in bronchioles due to slow air velocity and gravity. Particles less than one micrometer settle out in alveoli (industrial pollutants and cigarette smoke))
Removal of debris (Mucous (only as far as terminal bronchioles), cilia, alveolar macrophages, sneezing and cough)

Question 9

Intrapleural space

Answer 9

Liquid-filled area between visceral pleura and parietal pleura that provides fluid coupling between the two surfaces. Allows application of force from the chest wall and diaphragm to the lungs and vice versa. (Like two wet pieces of glass that slide easily against each other but resist being pulled apart)

Question 10

Muscles responsible for inspiration

Answer 10

75% from diaphragm
Remaining from intercostals (lift and expand rib cage)
Stenocleidomastoids and scalenes used in forced respiration to elevate ribs on rear pivot

Question 11

How does inspiration work?

Answer 11

Expansion of the chest lowers intrapleural pressure, which makes intrapulmonary pressure subatmospheric. The pressure differential between alveoli and upper respiratory tract causes air to flow towards the alveoli.

Question 12

Expiration

Answer 12

Passive
recoil of elastic elements in lungs. Lungs recoil until their force is balanced by outward force of chest wall. Active expiration uses abdominal muscles

Question 13

Respiratory resistance

Answer 13

Rtotal = Rairway + Rtissue + Rthoracic

Airway and pulmonary tissue resistance are also known as pulmonary resistance.

Question 14

What increases pulmonary resistance?

Answer 14

diseases such as pulmonary fibrosis, increased blood in the lungs (higher when lying down)

Question 15

What increases thoracic resistance?

Answer 15

increased intraabdominal pressure, higher when lying down, diseases of the rib cage

Question 16

Alveolar surface tension

Answer 16

Mutual attraction of water molecules at an air-water interface that tends to minimize the area of the interface.

Question 17

Compliance

Answer 17

Change in volume divided by change in pressure

Question 18

What decreases compliance?

Answer 18

Surface tension

Question 19

What increases compliance?

Answer 19

A saline-filled lung has greater compliance than a air-filled lung because the saline abolishes surface tension

Pulmonary surfactant also lowers surface tension, as well as detergent. (Surfactant also has an area-dependent effect on tension due to area-dependent changes in the packing of surfactant molecules)

Question 20

Composition of pulmonary surfactant

Answer 20

Phospholipid consisting mainly of dipalmitoyl phosphatidylcholine and 4 proteins

Question 21

Purpose of surfactant

Answer 21

Lowers surface tension of the ECM coating the lumenal alveolar surface. Makes tension decrease with decreasing area. They reduce the amount of work required to expand the lung and prevent the collapse of smaller alveoli

Causes decreased tension to compensate for increased pressure due to smaller radius

Question 22

Surfactant production begins at ___ weeks according to Rosen’s notes. (Note: This number was different for Walker in Anatomy)

It occurs under the control of ____.

Answer 22

32

(23 for anatomy)

cortisol

Question 23

Tidal volume

Answer 23

volume of normal breath - .5 L

Question 24

Inspiratory capacity

Answer 24

Maximum volume inhaled after normal exhale (3L) (Tidal Volume + Inspiratory reserve volume)

Question 25

Expiratory reserve volume

Answer 25

Maximum volume of forced exhale after normal exhale (1.5 L)

Question 26

Vital Capacity

Answer 26

Maximum volume inhaled and exhaled (tidal volume + inspiratory reserve volume + expiratory reserve volume) (4.5 L) Measures muscle effectiveness

Question 27

Residual volume

Answer 27

Volume of air in lungs after maximal exhale (1.5L) (25% total lung capacity)

Question 28

Functional residual capacity

Answer 28

Volume of air in lungs after normal exhale (expiratory reserve volume + residual volume) (3L) (50% of total lung capacity)

Balance of force between lung collapse and chest wall recoil

Question 29

FRC Equilibration technique

Answer 29

C1V1 = C2 (V1 + FRC) (C1 is known concentration of insoluble gas, V1 is volume of that gas, C2 is the concentration of insoluble gas after the gas comes to a constant concentration in the spirometer after equilibrating with the lungs.
Residual volume = Functional residual capacity - expiratory reserve volume

Question 30

Total Lung Capacity

Answer 30

Maximum volume of air lungs can hold

Question 31

Obstructive conditions, such as _____ have decreased FEV/FVC as a result of the increased airway resistance combined in some cases with loss of lung elasticity/recoil action.

Answer 31

asthma, COPD/emphysema

Question 32

Restrictive lung diseases

Answer 32

Characterized by a loss in total lung capacity
FEV/FVC increases
Atelectasis - collapse of part or entire lung
Consolidation - Filling of alveolar spaces with inflammatory exudates
Pleural effusion - heart failure, hypoproteinemia, infection, neoplasm
Pneumothorax
Respiratory Distress Syndrome - (infants - idiopathic (premature births), adults - acute (12-24 hours after trauma, near-drowning, acid respiration, etc.)) Reduced Functional residual capacity

Question 33

Anatomic dead space

Answer 33

The volume of conductive, non-respiratory passages

Question 34

Alveolar ventilation equation

Answer 34

Alveolar ventilation = alveolar air * number of breaths per minute
Alveolar air = TV(Total volume) - dead space volume

Question 35

Why is deeper, slower breathing more efficient than rapid, shallow breathing?

Answer 35

There is a constant contribution of dead space in rapid shallow breathing

Question 36

Arterial oxygen concentration is related to?

Answer 36

alveolar volume

Question 37

Arterial carbon dioxide concentration is related to?

Answer 37

1/(alveolar volume)

Question 38

How do you treat a pneumothorax?

Answer 38

Insert a chest tube connected to a water trap and vacuum line to pull out air for ~2 days. Once stable, remove tube by placing continuous suture around entry and remove tube at same time as pulling “purse strings” clamps