Respiratory

Question 0

What is the function of the upper respiratory tract?

Answer 0

To warm, moisten and filter the air before it reaches the lungs

Question 1

Why are humans dependent on lungs and a cardiovascular system to provide oxygen instead of just diffusion?

Answer 1

Diffusion rate is inversely proportional to the square of the distance, so for long distances it would take too long. Humans have a relatively low surface area to volume ratio which is overcome through the lungs. It also allows a control over the rate that tissues are provided with oxygen.

Question 2

What are the divisions of the lower respiratory tract and what are their respective general functions?

Answer 2

Lungs: organs for gaseous exchange and act as both a conduit for air flow as well a surface over which exchange occurs. The smaller unit of the lungs are the acinar.
Conducting airways: do not partake is gas exchange but facilitate gas movement.

Question 3

Define lung ventilation

Answer 3

The total volume of air in and out of the lungs. Defined by resp rate times tidal volume.

Question 4

Define hypocapnia

Answer 4

A loss of CO2 from the blood stream as can be induced from hyperventilation.

Question 5

Define tachypnoea

Answer 5

A raised respiratory rate.

Question 6

Describe the mechanism of ventilation generally.

Answer 6

Diaphragm and external intercostals contract increasing thoracic volume resulting in a reduction in pressure internally. This causes air to flow from outside to inside. Exhalation is relatively passive using the elastic recoil of the lung tissue. It can be forced using the abdominal muscles.

Question 7

What are the two types of ventilation impairment?

Answer 7

Obstructive (narrowing, inflammation, copd)

Restrictive (stiffening of lung tissue, pleural effusion/oedema)