Respiratory Systems

Question 1

What is Fick’s Law of diffusion?

Answer 1

Rate of transfer of a gas through a sheet of paper is proportional to the tissue area and the difference in gas partial pressure between the two sides and inversely proportional to tissue thickness.

Question 2

Define hypothetical pressure.

Answer 2

The pressure that a particular gas in a mixture would exert when occupying the same space and temperature on its own.

Question 3

What are some common respiratory adaptions?

Answer 3

• Large surface area
• Short distance of travel
• Ventilation of respiratory systems to maintain partial pressure gradient
• Perfusion of internal side of exchange surface to maintain partial pressure gradient.

Question 4

What are the advantages and disadvantages of external gills?

Answer 4

Adv - Increase surface area for gas exchange.

Dis - vulnerable to damage (except nudibranchs).

Question 5

How do insects obtain oxygen for respiration?

Answer 5

• Oxygen enters holes on body surface called spiracles
• Oxygen travels down tranchea
• Branches down into tracheoles which directly supply muscle with oxygen
• insects can open and close their tranchea to help move air through system.

Question 6

How do diving insects e.g. diving beetles obtain oxygen?

Answer 6

They carry a bubble from the surface down into the water which they use as a gill due to the partial pressure between the inside and outside of the bubble.

Question 7

What journey does air take during inhalation in humans/mammals?

Answer 7

Pharynx > larynx > trachea > bronchial tubes > lungs. (within the lungs > bronchioles > alveoli.)

Question 8

Describe the difference in respiratory adaptions of birds and humans.

Answer 8

• They half possess air sacs which ensure that new air is continuously being pumped into the lungs - unlike humans who have to wait for it (inefficient)
• Possess rigid lungs because air sacs are doing all the bellowing whereas humans are elastic
• no dead space
• countercurrent exchange systems - blood and air run in opposite directions to maintain partial pressure.

Question 9

Why is mammalian respiration so inefficient?

Answer 9

• Fresh air not moving during half breathing cycle
• Incoming air mixes with stale
• Dead space
• No countercurrent exchange.

Question 10

What are the functions of gills?

Answer 10

• Gas exchange
• Osmoregulation and ion balance
• pH regulation
• Immune function.