Question

place each of the following conditions in the proper category to predict whether the delivery of oxygen would be increased or decreased from normal sea-level conditions.
decreased temperature carbon monoxide binding to heme bohr effect alveolar po₂ of 86 mmhg decreased blood ph
increased hematocrit 75% saturation of hb leaving the alveolus tissue pco₂ of 43 mmhg tissue po₂ of 60 mmhg iron-deficiency anemia
increased o₂ delivery to tissues
o₂
decreased o₂ delivery to tissues
o₂

Explanation:

Step1: Analyze each condition for oxygen delivery

- **Increased \( O_2 \) delivery to tissues**:
- **Bohr Effect**: Promotes \( O_2 \) unloading at tissues (increased delivery).
- **Decreased blood pH**: Acidic environment (Bohr effect - like) increases \( O_2 \) release.
- **Increased hematocrit**: More RBCs, more \( O_2 \) carrying capacity.
- **Tissue \( PCO_2 \) of 43 mmHg**: Higher \( CO_2 \) (Bohr effect) increases \( O_2 \) unloading.
- **Tissue \( PO_2 \) of 60 mmHg**: Lower tissue \( PO_2 \) gradient, but wait - no, actually, lower tissue \( PO_2 \) means more \( O_2 \) can be released? Wait, no, let's recheck. Wait, normal tissue \( PO_2 \) is ~40 mmHg. So 60 mmHg is higher than normal? Wait, no, maybe I messed up. Wait, normal alveolar \( PO_2 \) is ~100 mmHg, tissue \( PO_2 \) ~40. So:
- **Decreased temperature**: Decreases \( O_2 \) unloading (so decreased delivery? Wait no, wait: lower temp increases Hb - \( O_2 \) affinity, so less unloading. Wait, I think I made a mistake earlier. Let's redo:
- Factors increasing \( O_2 \) delivery (more unloading at tissues):
- Bohr Effect (pH decrease, \( PCO_2 \) increase, temperature increase) → wait, the problem has "Decreased temperature" - that would decrease unloading (so decreased delivery). Wait, I need to recall:
- \( O_2 \) delivery depends on Hb saturation, Hb amount, and unloading at tissues.
- **Increased \( O_2 \) delivery**:
- Bohr Effect (when at tissues, \( PCO_2 \) high, pH low, temp high → increases unloading). But the conditions:
- Bohr Effect: yes, because it's a general effect that promotes unloading (so increased delivery).
- Decreased blood pH: acidic, Bohr effect → increased unloading.
- Increased hematocrit: more Hb, more \( O_2 \) carried.
- Tissue \( PCO_2 \) of 43 mmHg: higher than normal (~40), so Bohr effect → increased unloading.
- Wait, "Decreased temperature": lower temp → Hb - \( O_2 \) affinity increases → less unloading → decreased delivery. So that's in decreased.
- "Carbon monoxide binding to heme": CO binds Hb, reducing \( O_2 \) binding → decreased delivery.
- "Alveolar \( PO_2 \) of 86 mmHg": lower than normal (100), so lower Hb saturation → decreased delivery.
- "75% saturation of Hb leaving alveolus": normal is ~98%, so lower saturation → decreased delivery.
- "Iron - deficiency anemia": less Hb → decreased delivery.
- "Tissue \( PO_2 \) of 60 mmHg": higher than normal (~40), so lower \( O_2 \) gradient → less unloading → decreased delivery? Wait, no, if tissue \( PO_2 \) is higher, then \( O_2 \) doesn't need to unload as much. So:
- Let's list each condition:
1. Decreased temperature: Hb - \( O_2 \) affinity ↑ → less unloading → **Decreased \( O_2 \) delivery**
2. Carbon monoxide binding to heme: Hb can't bind \( O_2 \) → **Decreased**
3. Bohr Effect: promotes unloading → **Increased**
4. Alveolar \( PO_2 \) of 86 mmHg: lower than 100 → Hb saturation ↓ → **Decreased**
5. Decreased blood pH: Bohr effect → unloading ↑ → **Increased**
6. Increased hematocrit: more Hb → more \( O_2 \) → **Increased**
7. 75% saturation of Hb leaving alveolus: normal ~98% → less \( O_2 \) carried → **Decreased**
8. Tissue \( PCO_2 \) of 43 mmHg: higher than 40 → Bohr effect → unloading ↑ → **Increased**
9. Tissue \( PO_2 \) of 60 mmHg: higher than 40 → less gradient → unloading ↓ → **Decreased**
10. Iron - deficiency anemia: less Hb → **Decreased**
- So **Increased \( O_2 \) delivery**: Bohr Effect, Decreased blood pH, Increased hematocrit, Tissue \( PCO_2 \) of 43 mmHg
- **Decreased \( O_2 \) delivery**: Decreased temperature, Carbon monoxide binding to heme, Alveolar \( PO_2 \) of 86 mmHg, 75% saturation of Hb leaving alveolus, Tissue \( PO_2 \) of 60 mmHg, Iron - deficiency anemia

Step2: Place each condition in the correct category

- **Increased \( O_2 \) delivery to tissues**:
- Bohr Effect
- Decreased blood pH
- Increased hematocrit
- Tissue \( PCO_2 \) of 43 mmHg
- **Decreased \( O_2 \) delivery to tissues**:
- Decreased temperature
- Carbon monoxide binding to heme
- Alveolar \( PO_2 \) of 86 mmHg
- 75% saturation of Hb leaving alveolus
- Tissue \( PO_2 \) of 60 mmHg
- Iron - deficiency anemia

Answer:

Increased \( O_2 \) delivery to tissues:

• Bohr Effect
• Decreased blood pH
• Increased hematocrit
• Tissue \( \text{PCO}_2 \) of 43 mmHg

Decreased \( O_2 \) delivery to tissues:

• Decreased temperature
• Carbon monoxide binding to heme
• Alveolar \( \text{PO}_2 \) of 86 mmHg
• 75% saturation of Hb leaving the alveolus
• Tissue \( \text{PO}_2 \) of 60 mmHg
• Iron - deficiency anemia