Respiratory Physiology

Question 1

What are the three respiratory functions?

Answer 1

Ventilation

Oxygen utilisation

Gas Exchange

Question 2

What are the two steps of breathing

Answer 2

Ventilation

Oxygenation

Question 3

What is the conducting zone?

Answer 3

Areas of the respiratory system that moves air- the mouth, nose, pharynx, larynx, trachea, primary bronchi, all branches of bronchioles up to and including the terminal bronchioles

Question 4

What are the functions of the conducting zone?

Answer 4

Warm and humidify air, filtration, cleaning, transport

Question 5

Where in the lungs is there an improved ventilation to perfusion ration?

Answer 5

Lung bases

Question 6

Why does more perfusion occur towards the base of the lungs?

Answer 6

High concentration of capillaries surrounding respiratory alveoli

Question 7

What is the role of surfactant?

Answer 7

Dissolve within water to break surface tension to allow alveoli to inflate

Question 8

Which lung cells produce surfactant?

Answer 8

Type 2 alveolar cells/ pneumocytes

Question 9

What is anatomical dead space?

Answer 9

Anatomical dead space is air contained within the conductive airways of the respiratory system, that does not enter gas exchange regions

Question 10

What are the inspiratory muscles for respiration?

Answer 10

External intercostal

Sternocleidomastoid muscles

Anterior serration

Scaleni

Question 11

How is pulmonary function assessed?

Answer 11

Spirometry

Question 12

What is tidal volume?

Answer 12

The volume of gas inspire or expired in an unforced respiratory cycle

Question 13

What is inspiratory volume?

Answer 13

The maximum volume of gas that can be inspired curing forced breathing in addition to tidal volume

Question 14

What is expiratory reserve volume?

Answer 14

The maximum volume of gas that can be expired during forced breathing in addition to tidal volume

Question 15

What is residual volume?

Answer 15

The volume of gas remaining in the lungs after maximum expiration

Question 16

What is vital capacity?

Answer 16

The maximum amount of gas that can be expired after maximum inspiration

Question 17

What is inspiratory capacity?

Answer 17

The maximum amount of gas that can be inspired after a normal tidal expiration

Question 18

What is functional residual capacity?

Answer 18

The amount of gas remaining in the lungs after normal tidal expiration

Question 19

What does Fick’s law say about movement of gases?

Answer 19

Gas will move from areas of high concentration to a low concentration. The rate of diffusion is proportional to the concentration gradient

Question 20

Where in the brain are the respiratory centres?

Answer 20

The brain stem

Question 21

What is the Hering-Breuer inflation reflex?

Answer 21

Baroreceptors within lung tissue detect stretching and generate impulses to the medulla to depress the inspiration centre

Question 22

Explain chemical regulation of breathing

Answer 22

CO2 diffuses from blood into the CSF, dissolving in water to form carbonic acid. This lowers PH and stimulates central chemoreceptors to send impulses to the respiratory centre

Question 23

What is the average PH of arterial blood

Answer 23

7.4

Question 24

Why does oxygen move from alveoli into the blood?

Answer 24

The partial pressure of O2 within the alveoli is 105mmhg, within the capillaries it is 100mmhg. Oxygen follows the concentration gradient so moves into blood

Question 25

Name the layers of the pleura

Answer 25

Visceral pleura (inner layer)

Parietal pleura (Outer layer)