(Slides 34-41) | Respiratory Volumes, Capactites, adn Rate, Dead Space,

Measuring respiratory volumes can provide?

Important clues about a person’s respiratory health

• For the diagnosis of obstructive lung disease

What is special about residual volume?

It cannot be measured bc it is what is left inside the lungs

• w/o it lungs would collapse so it can not go out

What is spirometry?

• How much air you breathe in and out

• How quickly you can force air out

• How well your lungs and airways are functioning

What is a medical device that measures how much air you can inhale and exhale, and how fast you can blow it out?

Spirometer

What is the amount of air inhaled or exhaled with each breath under resting conditions?

Tidal Volume (TV)

What is the average tidal volume of a male and female?

500 ml

What is the amount of air that can be forcefully inhaled after a normal tidal volume inspiration?

Inspiratory Reserve Volume (IRV)

What is the amount of air that can be forcefully exhaled after a normal tidal volume expiration?

Expiratory Reserve Volume (ERV)

What is the amount of air remaining in the lungs after a forced expiration?

Residual Volume (RV)

What is the maximum amount of air contained in lungs after a maximum inspiratory effort?

Total lung Capacity (TLC)

• everything

What is the equation for total lung capacity?

TV + IRV + ERV + RV

What is maximum amount of air that can be expired after a maximum inspiratory effort?

Vital Capactiy (VC)

What is the equation for vital capacity?

TV + IRV + ERV

What is maximum amount of air that can be inspired after a normal tidal volume expiration?

Inspiratory capacity (IC)

What is the equation for Inspiratory capacity?

TV + IRV

What is volume of air remaining in the lungs after a normal tidal volume expiration?

Functional Residual Capacity (FRC)

What is the equation for Functional Residual Capacity?

ERV + RV

What does not participate in gas exchange?

The volume of airways or “dead spaces”

What are the three volume of airways or “dead spaces”?

• Anatomical dead space

• Alveolar dead space

• Total dead space

What makes up the conducting zone?

Nasal cavity → Terminal Bronchioles

It is usually hard to measure your anatomical dead space because it is within the conducting areas and organs of your body, what it a good rule of thumb to measure it?

By using the person’s weigh

• weight = anatomical dead space

What is the amount of tidal volume in the average person that reaches the respiratory zone and gets exchanged?

70%

• ~350 ml

• The rest stays in the anatomical dead space

What volume of air way or deadspace is being described:

• Volume of the conducting respiratory passages/conducting zone

• ~150 ml

• What is left while the rest of the air (70%) goes to respiratory zone to be exchanged

• 30% of tidal volume

Anatomical dead space

What volume of air way or deadspace is being described:

• Alveoli that cease to act in gas exchange

• Due to the collapse or obstruction of Alveoli

Alveolar dead space

What can cause an alveoli to collapse or be obstructed, leading them to not perform gas exchange?

• They’re collapsed (atelectasis)

• They’re blocked

• They’re not receiving blood flow (perfusion problem)

What volume of air way or deadspace is being described:

• Sum of alveolar and anatomical dead spaces

Total dead space

What is the total number of breaths/ respiratory cycles that occur each minute?

Respiratory Rate

What is the amount of air moved in or out of the lungs per minute.

Minute Ventilation (MV)

What is the equation for Minute Ventilation (MV)?

Tidal Volume (TV) x Respiratory Rate

What is the amount air reaching alveoli per minute?

Alveolar Ventilation (AV)

What is the equation for Alveolar Ventilation (AV)

(Tidal volume (TV) – Anatomical dead space) x Respiration rate

As we grow older, what happens to our respiratory rate?

It gradually decreases

• As we grow, our lungs get bigger and our muscles get stronger and it is easier for us to breath and there is more space

Besides having tiny lungs, why do younger ages have a higher respiratory rate?

Because they have higher metabolisms

• which require more oxygen

What maximizes alveolar ventilation?

Deep breathing

What is the average respiratory rate of an adult?

12-20

The rate of pulmonary and systemic gas exchange depends on what factors?

• Partial pressure difference of gases

• Surface area available for gas exchange

• Diffusion distance/ thickness

• Molecular weight and solubility of gases

What law is the total pressure of a gas mixture is the sum of the partial pressures of each gas present?

• basically each gas has its own pressure

Dalton’s law

Each alveolus has a?

Capillary bed surrounding it

What is partial pressure?

The amount of force exerted by one gas in a mixture of gases

The sum of the partial pressures of all the gases in a mixture equals?

The total pressure

For gas exchange (diffusion across) to occur in the lungs the?

Alveolar partial pressure must be greater the the blood partial pressure

• how blood gets oxygenated

What does it mean by Surface area available for gas exchange?

300,000,000 alveoli in each lung

• the more alveoli, the more surface area, the more gas exchange

A healthy lung’s surface are is?

~ 70m²

What is the diffusion distance/thickness of our respiratory membrane?

~ 0.5 micrometer

• very thing for gas exchange

What has the higher molecular weight, Oxygen (O2) or Carbon Dioxide (CO2)?

Carbon Dioxide

• 32 mol vs 44 mol

When a gas is light, what does it mean about its diffusion across a membrane?

It can diffuse easier

What is more soluble, Oxygen (O2) or Carbon Dioxide (CO2)?

Carbon Dioxide (CO2)

• it is 20-24 times more soluble

What law states that at a constant temperature the amount of a dissolved gas in a liquid is directly proportional to its partial pressure above the liquid?

Henry’s Law

• think of the fizz of soda

What is occurring due to the partial pressures of Alveolar Air and deoxygenated blood:

AA:

• O2: 105 mmHg

• Co2: 40 mmHg

DB:

• O2: 40 mmHg

• Co2: 45 mmHg

Gas exchange: External respiration

• O₂ diffuses from the alveoli into the pulmonary capillaries, oxygenating the blood.

• CO₂ diffuses from the blood into the alveoli, so it can be exhaled.

What is occurring due to the partial pressures of Oxygenated blood and Systemic Tissue cells:

OB:

• O2: 100 mmHg

• Co2: 40 mmHg

STC:

• O2: 40 mmHg

• CO2: 45 mmHg

Gas exchange: Internal Respiration

• O₂ diffuses from the blood into the systemic tissue cells.

  • This is how cells receive the oxygen they need for metabolism.

• CO₂ diffuses from the tissues into the blood.

  • This is how the blood picks up metabolic waste to return to the lungs.

This only happens in capillaries!!!

What is occurring due to the partial pressures of Oxygenated Blood?

• O₂: 100 mmHg

• CO₂: 40 mmHg

• Has high O₂ because it just loaded oxygen in the lungs

• Has low CO₂ because it just unloaded CO₂ into the alveoli

• Travels to tissues ready to deliver O₂ and pick up CO₂

• This blood is the starting point for internal respiration

What is occurring due to the partial pressures of Deoxygenated Blood?

• O₂: 40 mmHg

• CO₂: 45 mmHg

• Has low O₂ because it delivered oxygen to tissues

• Has high CO₂ because it picked up metabolic waste

• Arrives at the lungs ready to pick up O₂ and release CO₂

• This blood is the starting point for external respiration

What is occurring due to the partial pressures of Systemic Tissue Cells?

• O₂: 40 mmHg

• CO₂: 45 mmHg

• Low O₂ because cells constantly use oxygen for metabolism

• High CO₂ because cells constantly produce CO₂ as waste

• Ready to receive O₂ from the blood and dump CO₂ into the blood

• These gradients drive internal respiration

What is occurring due to the partial pressures of Alveolar Air?

• O₂: 105 mmHg

• CO₂: 40 mmHg

• High O₂ because fresh atmospheric air mixes with alveolar air

• Low CO₂ because CO₂ is constantly being exhaled

• Ready to load O₂ into blood and accept CO₂ from blood

• These gradients drive external respiration

What is when oxygen diffuses across the respiratory membrane from the alveolus to the capillary, whereas carbon dioxide diffuses out of the capillary into the alveolus?

• Gas exchange between alveoli and pulmonary capillaries

• O₂ diffuses from alveoli → blood (because alveolar O₂ is higher)

• CO₂ diffuses from blood → alveoli (because blood CO₂ is higher)

• Converts deoxygenated blood → oxygenated blood

External Respiration

What is when oxygen diffuses out of the capillary and into cells, whereas carbon dioxide diffuses out of cells and into the capillary?

• Gas exchange between systemic capillaries and tissue cells

• O₂ diffuses from blood → tissues (because blood O₂ is higher)

• CO₂ diffuses from tissues → blood (because tissue CO₂ is higher)

• Converts oxygenated blood → deoxygenated blood

Internal Respiration

What is the overall movement of oxygen (O₂) in the body?

• Atmosphere → Alveoli

• Alveoli → Blood (external respiration)

• Blood → Tissues (internal respiration)

• Used by cells for metabolism

• O₂ levels drop as blood moves through the body

What is the overall movement of carbon dioxide (CO₂) in the body?

• Produced by tissues during metabolism

• Tissues → Blood (internal respiration)

• Blood → Alveoli (external respiration)

• Exhaled into the atmosphere

• CO₂ levels rise as blood moves through the body

How do partial pressures determine gas movement?

Gases always diffuse from higher partial pressure → lower partial pressure

• Alveoli have higher O₂ → O₂ enters blood

• Blood has higher CO₂ → CO₂ enters alveoli

• Oxygenated blood has higher O₂ → O₂ enters tissues

• Tissues have higher CO₂ → CO₂ enters blood

• These gradients drive all gas exchange