Respiratory Physiology

Question 1

What is the difference between conducting zone and respiratory zone?

Answer 1

Respiratory zone is the site for gas exchange

Conducting zone is a passageway for airs to move in and out of lunges

Question 2

What are the function of conducting zone

Answer 2

Pathway of air that cleans humidifies and warms air

Question 3

Which cells are unique to respiratory zone?

Answer 3

alveolar cells
Type I = squamous epithelial cells
Type II = cubital cells
Aveolar macrophage

Question 4

Outline the autonomic nerve supply to the airway smooth muscle

Answer 4

Sympathetic control:
- B2 adrenergic receptors =Bronchodilation

Parasympathetic control:
- M3 muscarinic receptors = Bronchoconstriction

Question 5

What is respiration and what are the phases?

Answer 5

The process of supplying oxygen and removing CO2

1) Pulmonary ventilation
2) External Respiration
3) Gas transport
4) cellular respiration

Question 6

What is intrapulmonary pressure?

Answer 6

the pressure in alveoli

after exhale intrapulmonary = atmospheric pressure

Question 7

What is intrapleural pressure?

Answer 7

The pressure inside the pleural cavity

always negative to intrapulmonary pressure

Question 8

What is transpulmonary pressure?

Answer 8

Difference between intrapulmonary and intrapleural pressure

Question 9

What is Boyles law and how does it apply to respiration?

Answer 9

Pressure varies inversely to volume. If pressure increases volume decreases.
In respiration a vacuum effect is created, diagram contracts increasing intrapulmonary volume which decreases pressure, airs fills lung until pressure is the same as outside.

Question 10

How does the process of forced exhalation differ from quiet ventilation?

Answer 10

Quiet ventilation
MM relax volume decreases = inc. intrapulmonary pressure

Forced exhalation
Abdominal and intercostal muscles contract decreasing the intrapulmonary volume by pulling down the ribs. = increase intrapulmonary pressure

Question 11

What is lung compliance and what are its determinants?

Answer 11

Capacity of lungs to stretch and contract

Question 12

What is airway resistance and what is it determined by?

Answer 12

resistance to airflow in respiratory passageways

Question 13

What are the following respiratory volumes?

• Tidal
• Inspiratory reserve
• expiratory reserve
• residual

Answer 13

• Tidal - natural breathing
• Inspiratory reserve = deep inhale
• expiratory reserve = deep exhale
• residual = what is left after deep exhale

Question 14

What are the following respiratory capacities?

• Inspiratory capacity
• Functional residual capacity
• vital capacity
• total lung capacity

Answer 14

• Inspiratory capacity = Inspiratory reserve plus tidal
• Functional residual capacity = Expiratory reserve plus residual
• vital capacity = Tidal+expiratory+inspiratory
• total lung capacity = all volumes

Question 15

What is the difference between obstructive and restrictive ventilation disorder

Answer 15

Obstructive = restricted airflow (asthma) 
Ventilation = decrease ability of lungs to expand (cancer pregnancy, pneumonia)

Question 16

Which respiratory volumes and capacities would be increased with an obstructive disorder?

Answer 16

Residual volume increase - air is trapped.

Question 17

Which respiratory volumes and capacities would be reduced with a restrictive disorder?

Answer 17

Decrease in residual volume and inspiratory reserve volume

Question 18

What is daltons law and how can it compare to alveolar air?

Answer 18

Total pressure is the sum of the individual pressures of the gas component.

Alveolar air is similar to atmospheric air during inhaling, so during exhale, the air expelled is diffused and the air would be a mixture of alveolar and atmospheric air.

Question 19

What is Henry’s law and how does it affect the respiratory membrane?

Answer 19

In constant temperature, the amount of gas dissolved in a liquid is directly proportional to the partial pressure of the gas.

The pressure in alveoli is high and low in blood, so oxygen dissolves through diffusion into the blood which is a liquid through the respiratory membrane.

Question 20

What is Fick’s law and how does it affect the rate of diffusion across a respiratory membrane?

Answer 20

Rate of diffusion across a membrane.

ROD = K x A x ((P1-P2)/D)

Factors affecting diffusion

1) constant diffusion = K
2) Area of exchange = A
3) Partial gas pressure = P
4) thickness of barrier = D

Question 21

How is oxygen transported in the bloodstream?

Answer 21

1) Dissolved in plasma 1.5%

2) Bound to heam groups 98.5%

Question 22

What 3 factors can affect oxygen saturation of haemoglobin and how?

Answer 22

1) local availability of O2
2) local presence of CO2
3) Increase in temperature = decrease in O2

Question 23

How is CO2 transported in the bloodstream

Answer 23

1) Dissolved in CO2 plasma 7%
2) bound to haemoglobin 23%
3) Bicarbonate ions in plasma 70%

Question 24

What are the neural controls of ventilation and how do they work?

Answer 24

Control centres that control respiration. They are located in the medulla and pons.

1) Medullary centre
- ventral respiratory group - pace + rhythm of breathing
- Dorsal respiratory group = rhythm of breathing

2) Pontine centre: smooth transition between inspiration and expiration
3) limbic system and hypothalamus: influence higher centre and emotions
4) cortex: conscious control of breathing

Question 25

What is the difference between central and pheripheral chemoreceptors?

Answer 25

Central - can be desensitized with excess Co2

• Located at brainstem
• stimuli: Inc. Co2 + decrease PH
• Very sensitive
• Adaptable

Peripheral

• carotid body and aortic arch
• Stimuli decrease PH
• not sensitive
• not adaptable