Physiology - Respiration - Lecture #2

Spirometer

A device for measuring the amount of air breathed in and out

Surfactant

A phospholipid produced by type II cells when they are physically stretched

Inflated

A structure with high compliance can be ________ more easily

Surface Tension

A very strong force that involved the hydrogen bonding in water or the filled alveolar sacs

Asthma

Can be due to allergy or air pollution, intermittent attacks, airway smooth muscle contracts, thick mucus is secreted, airway resistance is increased

Chronic Bronchitis

Caused by smoking or infection, chronic inflammation of the bronchi, excessive mucus production, airway resistance is increased

Decrease

Cystic fibrosis is associated with a _________ in pulmonary compliance

Emphysema

Decreased elastic recoil of the lungs, increased airway resistance, decreased total area available for diffusion, and ventilation-perfusion inequality

Chronic Obstructive Pulmonary Disease (Emphysema)

Disease that is associated with an increase in pulmonary compliance due to loss of alveolar and elastic tissue

Small alveoli

Does surfactant have a higher concentration in small alveoli or large alveoli?

RR * (TV-DSV), DSV = Dead Space Volume

Equation for alveolar ventilation

Delta V/Delta P

Equation for lung compliance

P = 2T/r

Equation for the Law of Laplace

RR * TV, (RR = breaths/minute, respiratory rate, TV = tidal volume)

Equation for total volume inhaled or exhaled per minute

Surfactant is more concentrated there, without it, they tend to collapse

How are small alveoli preserved and the lungs stabilized?

Helium Dilution Technique

How can residual volume and functional residual capacity be measured?

Inspiratory reserve volume

If you take a huge deep breath, the extra volume on top of tidal volume

Daltons Law

In a mixture of gases, each gas has a partial pressure which is the pressure of that gas if it alone occupied the volume of the mixture

Increasing the TV

Is alveolar ventilation improved more with increased RR or increasing TV

Large

Is surface tension greater in small or large alveoli?

Respiratory Distress Syndrome

Premature infants have no surfactant, as a result, they have very stiff lungs, they have atelectalysis, and extreme effort is needed to breathe causing exhaustion

the air has low viscosity

Resistance of the airways is typically very low because....

Small, typically about 1 mmHg

Since F=deltaP/R, the deltaP needed to produce air flow will be very ________

Atelectasis

Small alveoli collapse and larger ones grow even larger

Compliance

The ability of the lung to be stretched open

Henrys Law

The amount of a given gas that dissolves in a given type of volume of liquid is directly proportional to the partial pressure. of that gas in equilibrium with that liquid

Vital Capacity

The maximum volume of air an individual can exhale, starting from a maximal inspiration (basically, everything added together except residual volume or IC + FRC -RV

Alveolar dead space

The portion of the alveoli that lack healthy blood supply and thus cannot participate in gas exchange

Wasted Ventilation/Physiological Dead Space

The sum of anatomic dead space and alveolar dead space

Alveolar ventilation

The total volume of fresh air reaching the alveoli per minute

Total lung capacity

The total volume of gas contained in the lungs at the end of a maximal inspiration

- The elastic recoil of the wall - The surface tension of the fluid-air interface

The two forces that oppose inflation of the alveoli

Anatomic dead space

The volume of air in conduction pathways left over from the preceding breath

Residual volume

The volume of air that cannot be exhaled

Expiratory reserve volume

The volume of exhaling extra all the way (below where you are at the end of exhaling tidal volume)

Tidal Volume

The volume you breathe in with no extra effort

Anti inflammatory drugs, bronchodilator drugs

Therapies for asthma

Cortisol administration to the mother, positive pressure breathing, surfactant replacement therapy

Therapies for respiratory distress syndrome in little babies

Inspiratory capacity

Tidal volume + inspiratory reserve volume

Connective tissue content + alveolar surface tension

What are the determinants of lung compliance

The residual volume or anything that uses residual volume to find (Function residual capacity, total lung capacity)

What cannot be measured with a spirometer>

Reduce surface tension, Increases lung compliance (makes it easier to breathe)

What does surfactant do and what is its purpose?

Shallow breaths result in low surfactant secretion, occasional deep breaths required (why they give you that little machine thingy)

What happens with surfactant in thoracic surgery patients

Low compliance

__________ means lungs are stiff and difficult to expand to a given volume

Functional residual capacity

expiratory reserve volume + residual volume, the volume of the lungs in end-expiratory