Oxygenation

Question 1

Pulmonary System

Answer 1

Airways and lungs

Ventilation
- Movement of air into/out of the lungs

Respiration
- Exchange of oxygen/carbon dioxide
- Alveolar capillary/capillary cell membrane

Question 2

Factors that Affect Ventilation

Answer 2

Rate: Fast (tachypnea) or slow (bradypnea)

Depth: Expansion of lungs
- Affects oxygen and carbon dioxide levels in the blood

Lung compliance: Ease of inflation.
- Reduced by increased lung water (edema), loss of surfactant, or conditions that cause elastin fibers in the lungs to be replaced with scar tissue (collagen).

Lung elasticity (elastic recoil): Think rubber band
- Alveoli that have been overstretched (emphysema) lose their elastic recoil over time. This loss of elasticity allows the lungs to inflate easily but inhibits deflation, leaving stale air trapped in the alveoli.

Airway resistance: Resistance to airflow
- The larger the diameter of the airway, the more easily air moves through it.

Question 3

Respiration (Gas Exchange)

Answer 3

External Respiration
- Occurs in the alveoli of the lungs
- O2 diffuses across the alveolar capillary membrane into the blood of the pulmonary capillaries
- CO2 diffuses out of the blood and into the alveoli to be exhaled

Internal Respiration
- Occurs in body organs/tissues
- O2 diffuses from the blood through the capillary cellular membrane into the tissue cells where it’s used for metabolism.

Question 4

Control of Breathing

Answer 4

Chemoreceptors
- Medulla of brainstem, carotids, aorta
- Detect changes in blood pH, O2, CO2
- Send messages to resp center in brainstem
- Maintain pH, O2 (PO2) and CO2 (PCO2)

Lung receptors
- Lung and chest wall
- Sensitive to breathing patterns, expansion, compliance, resistance, irritants