The Question is from neet-zoology breathing-and-exchange-of-gases transport-of-gases, and it was created by the author T HARITHA

Question

A patient suffering from chronic bronchitis experiences difficulty in breathing and exhibits cyanosis.  Blood gas analysis reveals significantly reduced oxygen saturation. Which of the following combinations of factors MOST accurately explains this scenario?

T HARITHA · Accepted Answer

## CORE INFORMATION
✓ **Answer**: A
## CONCEPT FRAMEWORK
 **Primary Concept**: Gas exchange in the lungs and the effect of chronic bronchitis.
 **Related Topics**: Respiratory physiology, diffusion, partial pressures of gases, cyanosis.
 **Prerequisites**: Understanding of the process of gas exchange in alveoli, factors affecting diffusion rate, and the causes of cyanosis.
## SOLUTION PATHWAY
**Given Information**:
  Chronic bronchitis, difficulty breathing (dyspnea), cyanosis, reduced oxygen saturation.
  Cyanosis indicates low blood oxygen levels.
**Method & Steps**:
 1. Understand the process of gas exchange in the alveoli. Oxygen diffuses from the alveoli into the pulmonary capillaries, and carbon dioxide diffuses from the capillaries into the alveoli. This process depends on several factors, including the surface area available for diffusion, the thickness of the diffusion membrane (the alveolar-capillary membrane), and the partial pressure difference of the gases.
  Reasoning: Chronic bronchitis is characterized by inflammation and excessive mucus production in the bronchi and bronchioles. This leads to airway obstruction and reduced airflow into the alveoli.
  Formula/Rule: Fick's Law of Diffusion:  $J = -D \cdot A \cdot \frac{ΔC}{Δx}$ where J is the diffusion flux, D is the diffusion coefficient, A is the surface area, ΔC is the concentration difference, and Δx is the diffusion distance (membrane thickness).
 2. Analyze how chronic bronchitis affects the factors in Fick's Law. The inflammation and mucus in chronic bronchitis increase the thickness of the diffusion membrane ($Δx$ increases), reducing the diffusion rate.  Furthermore, the airway obstruction reduces the effective surface area ($A$ decreases) available for gas exchange.
  Working:  An increase in $Δx$ and a decrease in $A$ both result in a decrease in the diffusion flux ($J$) according to Fick's Law. This leads to reduced oxygen uptake into the blood, resulting in low oxygen saturation and cyanosis.
  Key Point:  The combined effect of increased membrane thickness and decreased surface area significantly impairs gas exchange, leading to the observed symptoms.
 3. Evaluate the options. Only option A correctly reflects the effects of chronic bronchitis on the diffusion membrane and surface area.
  Result: Increased thickness of diffusion membrane and decreased surface area.
  Verification: This combination accurately explains the reduced oxygen saturation and cyanosis observed in the patient with chronic bronchitis.
 ## OPTION ANALYSIS
A ✓: Increased thickness of diffusion membrane and decreased surface area. This accurately reflects the physiological changes in chronic bronchitis, leading to impaired gas exchange and reduced oxygen saturation.
B :x: Decreased thickness of diffusion membrane and increased surface area. This would actually improve gas exchange, contradicting the observed symptoms.
C :x: Increased thickness of diffusion membrane and increased surface area. While the increased thickness would impair diffusion, the increased surface area would partially counteract this effect. This is not the most accurate explanation.
D :x: Decreased thickness of diffusion membrane and decreased surface area. This would severely impair gas exchange, but chronic bronchitis does not cause a decrease in the diffusion membrane thickness.
 ## LEARNING AIDS
 **Common Mistakes**:
  1.Focusing only on one factor (e.g., thickness of membrane) instead of considering the combined effects of multiple factors on gas exchange.
   How to avoid: Remember Fick's Law and consider all factors influencing diffusion.
  2.Confusing the effects of other respiratory diseases with chronic bronchitis. 
   How to avoid: Understand the specific pathological changes associated with chronic bronchitis.
 **Quick Tips**:
  1.Remember that chronic bronchitis causes airway obstruction and inflammation, leading to both reduced surface area and increased diffusion distance.
  2.Relate the symptoms (dyspnea, cyanosis, low oxygen saturation) to the underlying physiological changes in gas exchange.

T HARITHA · Answer

The correct Option is "Increased thickness of diffusion membrane and decreased surface area"

T HARITHA · Answer

Decreased thickness of diffusion membrane and increased surface area

T HARITHA · Answer

Increased thickness of diffusion membrane and increased surface area

T HARITHA · Answer

Decreased thickness of diffusion membrane and decreased surface area

NEET Zoology Breathing And Exchange Of Gases Transport Of Gases MCQs

Select Topic

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

NEET Subjects

Our Bots

Company