respiration 4

Question 1

what are the 2 categories of lung disease?

Answer 1

obstructive- reduction of flow through airways
restrictive- reduction in lung expansion

BOTH REDUCE VENTILATION

Question 2

What are some causes of narrowing of airways in obstructive lung disease?

Answer 2

Inflammation
Bronchoconstriction- Asthma
Excess secretions

In all cases, there is an increased resistance to flow rate

Question 3

How can you identify Obstructive Lung Disease in Spirometry?

Answer 3

• FEV1 (Forced Expiratory Volume in 1 sec) is less than 80% of FVC (Forced Vital Capacity)
• Volume-time curve shows a concave shape
• Initial flow and peak flow can be similar to normal
• Sharp fall in flow-rate

Question 4

what are examples of obstructive lung diseases?

Answer 4

Chronic bronchitis- persistent cough and excessive mucus production

Asthma- inflammatory

Chronic obstructive pulmonary disease (COPD)- structural changes

Emphysema- loss of elastin

Question 5

What is Asthma?

Answer 5

• Inflammatory disease with hyper-active airways
• Two types:
  1. Atopic (Extrinsic): Triggered by allergies
  2. Non-Atopic (Intrinsic): Triggered by infections, cold air, stress, exercise, irritants
• Characterized by:
  ▪︎ Movement of inflammatory cells into airways
  ▪︎ Release of inflammatory mediators like histamine
  ▪︎ Bronchoconstriction

Question 6

what are the treatments of asthma?

Answer 6

Short-acting treatments:
- β2-adrenoreceptor agonists (e.g., salbutamol)
- Causes airway dilation

Longer-term treatments:
- Inhaled steroids (Glucocorticoids like beclometasone)
- Reduce inflammatory responses
- Long-acting β-adrenoreceptor agonists

Question 7

What defines a Restrictive Lung Disease?

Answer 7

Reduced chest expansion
- Chest wall abnormalities
- Muscle contraction deficiencies

Loss of compliance (fibrosis)
- Aging process
- Increased collagen
- Environmental factor exposur

Question 8

How can you identify restrictive Lung Disease in Spirometry?

Answer 8

Reduced Vital Capacity
- Total volumes are decreased
- FEV1% can remain unaltered or even increase
- Flow-volume loop shows normal shape but reduced volumes

Question 9

what is asbestosis?

Answer 9

slow build up of fibrous tissue leading to a loss of compliance

Question 10

How is breathing controlled consciously?

Answer 10

• Breathing is primarily an involuntary mechanism
• Can be temporarily altered consciously
• Examples include:
  ▪︎ Hyperventilation
  ▪︎ Breath Holding
• Conscious control is temporary and will be overridden if necessary

Question 11

What are the key respiratory centres in the Medulla?

Answer 11

1. Dorsal Respiratory Group (DRG)
   - Controls quiet Inspiration
   - Spontaneously active with periods of activity and shutdown
2. Ventral Respiratory Group (VRG)
   - Controls Inspiration and Expiration (forced)
   - Inactive during quiet respiration
   - Helps control forceful breathing

Question 12

What is the Hering-Breuer Reflex?

Answer 12

• Involves stretch receptors in the lungs
• Send signals to medulla to limit inspiration
• Prevents over-inflation of the lungs

Question 13

What are the types of Chemoreceptors and their functions?
1. Central Chemoreceptors
- Monitor cerebro-spinal fluid
- Sense carbon dioxide and pH
- Indirect response to CO2 rise stimulates increased ventilation

2. Peripheral Chemoreceptors
   - Located in carotid body and aortic arch
   - Respond to:
   ▪︎ Increase in CO2
   ▪︎ Decrease in pH
   ▪︎ Decrease in O2
   - Stimulation leads to increased ventilation