L1

Question 1

How many alveoli in the lungs?

Answer 1

600 million

Question 2

Diameter of an alveoli?

Answer 2

0.3mm

Question 3

What type of epithelial cells are alveoli composed of?

Answer 3

Simple squamous epithelial cells

Question 4

What is the thickness of the alveoli surface?

Answer 4

Around 0.3micrometers (um), extremely thin barrier between alveolar and capillary cells

Question 5

What are pores of Kohn?

Answer 5

Small pores within each alveoli that evenly disperse surfactant to reduce surface tension for easier alveolar inflation. Also provide gas interchange between adjacent alveoli.

Question 6

Approximately how much oxygen leaves the alveoli and enters the blood each minute at rest?

Answer 6

250ml

Question 7

Approximately how much carbon dioxide diffuse from the blood to the alveoli each minute at rest?

Answer 7

200ml

Question 8

What are the functions of the lungs?

Answer 8

Primary function of the lung is to take up oxygen from the alveoli gas into the pulmonary capillary blood and reduce the amount of carbon dioxide of the blood by moving it to the alveoli
Other include:
- Acid-base balance
- Vocalisation
- Water and heat loss
- Defence against pathogens
- Blood reservoir filtering unwanted materials from the circulation and metabolism

Question 9

What is the lungs conducting zone?

Answer 9

Zones 1-16
Transport of gases between the atmosphere and the alveoli. Contains the anatomical dead space (150ml). Includes the trachea and terminal bronchioles

Question 10

What is the lungs respiratory zone?

Answer 10

Zones 17-23 (2.5-3L)

Alveolated region where gas exchange occurs, includes transitional region. Bronchioles, alveolir ducts and alveoli

Question 11

What is external respiration?

Answer 11

Oxygen uptake (VO2) to provide O2 for transport by the blood and utilisation by the tissues
Carbon dioxide output (VCO2) to clear metabolically produced CO2, CO2 derived from buffering of acids, and maintenance of arterial pH

Question 12

What is internal respiration?

Answer 12

Oxygen consumption by the tissues for ATP production in mitochondria
Carbon dioxide production from the breakdown of carbon chains e.g. in the TCA cycle

Question 13

Define total ventilation (VE) and its equation

Answer 13

The total amount of air that flows out of the respiratory system in a minute
VE = tidal volume (VT ) x breathing frequency (fr)

Question 14

What is the physiological dead space (VD)?

Answer 14

includes the conducting zone and any other lung space that doesn’t undergo gas exchange

Question 15

Define alveolar ventilation (VA)?

Answer 15

The portion of air that reaches the alveoli and participates in gas exchange

Question 16

What is hyperventilation?

Answer 16

Breathing more quickly, breathing more than required to clear metabolically produced CO2; PACO2 will fall

Question 17

What is hypoventilation?

Answer 17

Breathing slower, breathing less than required to clear metabolically produced CO2; PACO2 will rise

Question 18

What is hyperpnoea?

Answer 18

The appropriate increase in ventilation in response to exercise