Respiratory 2

What are the three physiological factors that are required for gas exchange to occur?

1. Ventilation 2. Perfusion 3. Diffusion

What are the two situations at which Tidal volume varies in the same animal?

1. Ventilation 2. Thermoregulation

2/3rds of the respiratory work is needed to overcome _____, while 1/3rd of the respiratory work is needed to overcome _____

2/3rds - Surface tension (collapsing force) 1/3rds - Elastic forces of the tissue

What are the two components that make up physiological VD?

Anatomic VD + Alveolar VD

What exactly does surfactant do in order to decrease surface tension?

Breaks the Hydrogen bonds between the H2O molecules at the alveolar surface

What hormone stimulates the release of surfactant?

Cortisol

What does alveolar collapse do to the total cross sectional area?

Decreases

When an animal pants, what happens to their Tidal volume?

Decreases

Restrictive lung disease is known to decrease what pulmonary volume/capacity?

Decreases Total lung capacity

If pulmonary tissue (epithelial cells) were to enlarge or become thicker, what factor that ensures gas exchange is being disturbed? (i.e. what stops gas exchange from occurring)

Diffusion

Obstructive lung disease makes it more difficult to perform what phase of ventilation?

Expiration

What term is defined as the maximum additional volume that can be expired at rest after a normal expiration?

Expiratory reserve volume

What term is defined as the volume remaining in the lungs at rest after normal exhalation?

Functional residual capacity

________ = Expiratory reserve volume + Residual volume

Functional residual capacity

What is the physiological condition at which there is a delay between the change in intrapleural pressure and lung volume?

Hysteresis loop

Obstructive lung disease is marked by an increased _____ and a decreased _______

Increased residual volume Decreased Vital capacity

When an animal sighs or yawns what happens to their Tidal volume?

Increases

Restrictive lung disease typically is marked by difficulty performing which phase of respiration?

Inhalation

What term is defined as the maximum additional volume that can be inspired at rest after a normal inpiration?

Inspiratory reserve volume

What happens to the Critical Opening Pressure of an animal with surfactant diluted by alveolar edema?

It extends (larger airway pressure) and requires more time/effort to reach the opening pressure threshold

What pulmonary volume cannot be measured in healthy individuals because it represents the amount of volume that will remain after the lungs collapse?

Minimal volume

What measurement of respiration closely resembles cardiac output?

Minute ventilation (VE)

What term is described as the volume of air breathed per minute?

Minute ventilation (VE)

Asthma and Bronchitis are typically examples of what type of lung disease?

Obstructive Lung Disease

What type of lung disease is due to the narrowing of an airway?

Obstructive Lung Disease

If some pulmonary capillaries were to collapse, what factor that ensures gas exchange is being disturbed? (i.e. what stops gas exchange from occurring)

Perfusion

When an animal has Obstructive Lung Disease, why does their pleural space pressure increase, and what is the pathological consequence of this?

Pleural space pressure increases because there is an increased effort from expiratory muscles in order to generate a pressure large enough to overcome the obstruction

Alveolar surface tension resists ______ and promotes ______

Resists inflation and promotes deflation

If lung compliance decreases or the chest wall stiffens, what form of lung disease is generated?

Restrictive Lung Disease

What form of lung disease is marked by the lungs being incapable of fully expanding, and is also referred to as "small lung"?

Restrictive Lung Disease

Interstital lung disease (fibrosis), Alveolar edema, Pleural disease, and neuromuscular disease are all common conditions resulting in what form of lung disease?

Restrictive Lung disease

Do smaller or larger alveoli contain a more concentrated percentage of surfactant? Why?

Smaller alveoli contain an increased concentration of surfactant - this is because smaller alveoli have much larger degrees of collapsing pressure and require more surfactant to counteract this force (prevents alveolar collapse at low volumes)

Under conditions where surfactant is not present, the pressure in a smaller alveolus is going to be ______ than the pressure in a slightly larger alveolus

Smaller alveolus has greater pressure than the larger alveolus (this condition would result in expulsion of the air from the small alveolus toward the larger alveolus as it follows the generated pressure gradient - this leads to alveolar collapse)

What is the name of the instrument used to measure respiratory volumes in a live animal?

Spirometer

When surfactant is present, surface tension _____ as radius of the alveolus decreases

Surface Tension decreases as alveolar radius decreases

What causes the phenomenon known as pressure-volume hysteresis?

Surface tension in the alveoli - essentially this phenomenon is based on the pressure needed to overcome the surface tension of the alveoli to experience inspiration

What is the name of the lipid/protein mixture that prevents alveolar collapse? What cells produce this compound?

Surfactant - produced by Type II alveolar epithelial cells (pneumocytes)

The resistance to air flow due to the surface tension, determines what factor regarding respiration?

The amount of pressure required to get air into and out of the lungs

What does Critical Opening Pressure refer to in regards to the Hysteresis loop?

The point at which the lungs begin to inflate

What is residual volume?

The volume of air remaining in the lungs after a maximum expiration

What is deadspace?

The volume of air that does not participate in gas exchange

What can pain and neuromuscular disease do to surfactant levels?

This can decrease the production of surfactant

Why is surfactant deficiency common among premature newborns?

This is because surfactant is produced late in gestation (~32 wks) and animals born too soon do not accumulate enough surfactant to stabilize their lungs

Why do giraffes have relatively low VD/VT ratios?

This is because their tracheas are narrower meaning they have smaller conducting zones which decrease their deadspace

Why does the surface tension contribute to the collapse of the alveoli?

This is because, at the H2O/air interface, the water molecules have high attractive forces toward one another

What term is defined as the amount of air inhaled or exhaled in one breath during relaxed, quiet breathing?

Tidal Volume

What term is defined as the maximum air the lungs can hold?

Total lung capacity

What is meant by "wasted ventilation"?

VD/VT - the fraction of air that isn't being used for gas exchange

What term is defined as the maximum volume that can breathed entirely?

Vital capacity

_______ = inspiratory reserve volume + tidal volume + expiratory reserve volume

Vital capacity

VE (Minute Ventilation) = _____ x _____

Vt x f (Tidal volume X frequency)

What is the approximate tidal volume for resting animals?

~10 mL/kg BW