4.2c Chemical Control of ventilation

What is diffusion?

What is diffusion?

Gases move from high to low concentrations.

REMEMBER: It’s caused by Type 1 alveolar cells

what is gas exchange?

Oxygen enters the blood and carbon dioxide enters the alveoli

What is macrophages?

A protective layer that surrounds alveoli.

What is surfactant?

a protective INNER layer of alveoli that prevents alveoli from sticking to themselves

Partial pressure of oxygen ___ at it moves away from alveoli to tissue cells

decreases

The partial pressure of carbon dioxide ___ as it moves from tissue cells to alveoli

increases

___ is only way Oyxgen can be carried throughout the body

Hemoglobin bonding

what is % saturation?

number of hemoglobin with an oxygen molecule attached to each heme group

What does 100% O2 saturation mean?

Each hemoglobin is bound to the maximum 4 oxygen molecules

What % saturation indicates that the cell is at rest?

when O2 saturation is at 77 - 75%

What are the 3 ways CO2 could be transported across the body?

• Dissolved CO2

• Bound to Hemoglobin

• HCO3 (bicarbonate)

CO2 reacts with water to form ____

Carbonic acid (H2CO3)

Explain how bicarbonate transport carbon dioxide

• Carbonic Acid (H2CO3) dissociates into H+ (Hydrogen ions) & HCO3 (bicarbonate ions)

• Electrical neutrality is maintained by moving CI- ion into RBC when HCO3 moves out; “chloride shift.”

• Increases in CO2 decrease the pH of blood (making it more acidic)

• HCO3 converts back to CO2, and you exhale it

• Process reverses when blood reaches alveoli

What do chemoreceptors in blood vessels measure?

Chemoreceptors measure changes in:

• Blood pH

• PO2

• PCO2