Structures and functions of the respiratory system

Question 1

What is that function of the respiratory system?

Answer 1

To allow efficient exchange of gases between the atmosphere and bloodstream. This ensures adequate O2 can be dissolved, and Co2 removed from the bloodstream, modulating blood pH levels and maintain g homeostasis

Question 2

What is the region called where the main organs responsible for breathing are found?

Answer 2

The thoracic cavity

Question 3

Name the membranes that enclose the lungs and any attachments they make…

Answer 3

Double layered PLEURAL MEMBRANES

Parietal pleura (outer layer) attaches to the chest wall thus allowing lungs to be pulled in an out.
Visceral pleura cover the lungs, blood vessels, nerves and bronchi.

Question 4

What is the function of the pleural membranes?

Answer 4

To allow the parietal and visceral layers to slide over each other, allowing lung expansion & contraction with almost no friction
(n.b. Lungs also attach to the diaphragm but not through pleura)

Question 5

Two types of cells line the respiratory tract (including the trachea) leading to thd left and right main bronchi. What are they called?

Answer 5

Goblet cells (specialised columnar epithelial cells)

AND

Ciliated
columnar epithelial cells

Question 6

What is the function of type II alveolar cells?

Answer 6

The septal cells secrete phospholipid rich surfactant which allows frictionless expansion of the capillary-lined alveolar sacs.

n.b. they also replenish type I alveolar cells which cannot replicate

Question 7

Explain the structure and function of type I alveolar cells

Answer 7

Very thin, flat, squamous cells (giving large surface area) that line the epithelium of the alveolar sacs.

They allow very fast diffusion in gas exchange between air in the alveoli and blood in the pulmonary capillaries

Question 8

How does O2 diffuse into the pulmonary capillaries from the alveoli?

Answer 8

Down the pressure gradient

high to low partial pressure

Question 9

In expiration, why can CO2 move down the partial pressure gradient into the alveoli?

Answer 9

The partial pressure of C02 is higher in pulmonary capillaries than in the alveoli, thus gases move from high partial pressure to low

Question 10

What unit is partial pressure measured in?

Answer 10

mmHg

millimeters of mercury

Question 11

How do we calculate the partial pressure of a gas?

Answer 11

Partial pressure of a gas = Total pressure (mmHg) x Gas (%)