Respiratory System

Question 1

Define Cellular Respiration

Answer 1

Intracellular Metabolic Processes carried out within the mitochondria, which uses oxygen and produces CO2 while deriving energy from nutrient molecules

Question 2

Define external respiration

Answer 2

Entire sequence of events in exchange of oxygen and carbon dioxide between the external environment and tissue cells.

Question 3

Describe the 4 steps of external respiration

Answer 3

1. Air alternately moves in and out of lungs so that it can be exchanged between atmosphere and air sacs of lungs. This is accomplished by mechanical act of breathing (ventilation). The rate of ventilation is regulated to adjust the flow of air between the atmosphere and alveoli according to metabolic needs
2. O2 and CO2 exchanged between air in alveoli and blood in pulmonary capillaries through diffusion
3. Blood transports oxygen and carbon dioxide between lungs and the tissues
4. O2 and CO2 are exchanged between blood in systemic capillaries and tissue walls.

Question 4

What are other functions of the respiratory system?

Answer 4

• Water loss and heat elimination
• Enhance venous return
• Maintain normal acid-base balance by altering the amount of H+-generating CO2 exhaled
• Enables speech, singing, vocalisation
• Defends against inhaled foreign matter
• Removes, modifies, activates/inactivates various materials passing through the pulmonary circulation as all blood must pass through the lungs before being returned to systemic circulation
• Sense of smell

Question 5

What types of cells do the alveoli contain?

Answer 5

1. Type 1
2. Type 2
3. Alveolar macrophages

Question 6

What is the function of type 1 alveolar cells

Answer 6

They are squamous cells that line the alveoli

Question 7

What is the function of type 2 alveolar cells

Answer 7

They secrete pulmonary surfactant

Question 8

What is the function of alveolar macrophages

Answer 8

Phagocytose foreign material

Question 9

What is the function of the alveolar-capillary membrane?

Answer 9

• Separates air in the alveoli and blood in the capillaries
• Formed by type 1 alveolar cells, endothelial cells and basement membrane.

Question 10

How does the alveoli facilitate diffusion?

Answer 10

• Decreased diffusion distance
• Increased surface area

Question 11

What are the 2 types of pleura in the thoracic wall?

Answer 11

1. Visceral pleura that lines the lungs
2. Parietal pleural that lines the thoracic wall

Question 12

What is the function of the pleural sac?

Answer 12

• Filled with intrapleural fluid
• Lubricates the pleural surfaces as they slide past each other during respiratory movements
• Causes surface tension