oxygen 1-15

Oxygenation

movement of oxygen into blood

Perfusion1

movement of oxygenated blood to tissues1

Why is oxygen and perfusion required

cellular function & survival

Factors Essential for Normal Respiration

• Patent airways (open, unobstructed)

• Healthy alveoli (gas exchange)

• Intact cardiovascular system

• Adequate blood supply for O₂ transport

Upper Airway

• Nose

• Pharynx

• Larynx

• Epiglottis

• Function: warm, filter, humidify air

Lower Airway

• Trachea

• Mainstem bronchi

• Segmental bronchi

• Bronchioles

• Function: air conduction, mucociliary clearance, surfactant production

Right lung

3 lobes

Left lung

2 lobes

Alveoli

site of gas exchange

Surfactant does what ?

prevents alveolar collapse

Pleura

• Visceral = covers lungs

• Parietal = lines chest cavity

Ventilation

air in & out of lungs

Respiration

gas exchange (O₂ & CO₂)

Perfusion

blood flow to tissues

Perfusion, ventilation, respiration

All three are required for oxygenation

Inspiration (Active):

• Diaphragm contracts & flattens

• Ribs move up & out

• Intrapulmonary pressure ↓

• Air moves into lungs

Expiration (Passive):

• Diaphragm relaxes

• Lung volume ↓

• Pressure ↑

• Air moves out

The Diaphragm

• Dome-shaped muscle

• Separates chest & abdomen

• Innervated by phrenic nerve (C3–C5)

• Responsible for ~75% of quiet breathing

Gas Exchange (Respiration)

• Occurs in alveoli & capillaries

• Happens by diffusion

• Moves from high → low concentration

Oxygen & Carbon Dioxide Transport

• O₂ carried by hemoglobin (97%)

• CO₂ transported mainly as:

  • Bicarbonate (70%)

  • Bound to hemoglobin (23%)

  • Dissolved in plasma (7%)

Hypoxia:

lack of oxygen at cellular level

Dyspnea

subjective shortness of breath

Hypoventilation:

↓ breathing → CO₂ retention

Hyperventilation:

↑ breathing → ↓ CO₂

Heart

pumps oxygenated blood

SA node

pacemaker

AV node

impulse delay

Bundle of His (Atrioventricular Bundle)

ventricular conduction

RBC do what

transport oxygen

Dysrhythmias

abnormal rhythms

Angina

temporary ischemia

Myocardial infarction

permanent damage

Heart failure

• inadequate pumping → fluid buildup

Factors Affecting Oxygenation

• Smoking

• Obesity

• Anxiety & stress

• Environmental pollutants

• Medications (opioids, beta blockers)

• Age-related changes

Infant Respiratory System

• Rapid respirations

• Abdominal breathing

• Immature alveoli

• Surfactant develops at 24–28 weeks

• Adequate by 35–36 weeks