Exchange- Ventilation

Question 1

Explain how goblet cells are adapted for their function

Answer 1

Ribosomes – to make proteins
Mitochondria – produce ATP for (protein) synthesis/moving vesicles
RER/SER – for producing proteins/lipids
Golgi – Vesicles to transport molecules to the cell surface
membrane/modification of proteins/ lipids

Question 2

What is boyles law?

Answer 2

the volume of gas is inversely proportional to pressure (when temperature is constant).
As volume increases, pressure decreases and vice versa

Question 3

Model answer- inspiration and expiration

Answer 3

• During inspiration, air passes through the nose and mouth, down the trachea, through the bronchus/bronchi, bronchioles and finally reaches the alveoli (reverse for expiration)
• During inspiration , external intercostal muscles contract and internal intercostal muscles relax.
• The ribs move up and out and the diaphragm contracts and
flattens
• This increases the chest volume, decreases pressure, and air
moves in down a pressure gradient
• During expiration, external intercostal muscles relax, internal intercostal muscles contract.
• The ribs move down and in. The diaphragm relaxes and curves up
• This decreases chest volume, increases pressure, and air moves
out down a pressure gradient

Question 4

What is forced expiration?

Answer 4

• An active process – using more muscles to actively expire and exhale more CO2
• The abdominal muscles contract, pushing the diaphragm upwards
• The internal intercostal muscles contract, pulling the ribs downward
• This gives a larger and faster expiration, used

Question 5

What happens when the volume of the thoracic cavity increases?

Answer 5

the volume of the
lungs increases and the pressure decreases (now lower than the
atmosphere) – air rushes into the lungs, down the pressure gradient.

Question 6

What happens when the volume of the thoracic cavity decreases?

Answer 6

the volume of the
lungs decreases and the pressure increases (now higher than the
atmosphere) – air is forced out of the lungs, down the pressure gradient

Question 7

Adaptations- alveoli

Answer 7

Each lung contains millions of alveoli which have folded walls so Large surface area for increased rate of
diffusion

Question 8

Adaptations- alveolus

Answer 8

Alveolus wall is made of one layer of
flattened epithelium cells so Short diffusion distance for increased rate of
diffusion

Question 9

Adaptations- capillary

Answer 9

Capillary wall is made of one layer of
flattened endothelium cells so Short diffusion distance for increased rate of
diffusion

Question 10

Adaptations- ventilation

Answer 10

Ventilation brings in fresh supplies of
atmospheric air so Maintains a high
concentration gradient for fast diffusion

Question 11

Adaptations- blood circulation

Answer 11

Circulation of blood continually replaces blood high in O2 with blood low in O2 so Maintains a high concentration gradient for fast diffusion

Question 12

Alveoli Gas Exchange Summary

Answer 12

As we exhale, the concentration of CO2 in the alveoli will decrease. As we inhale, the concentration of O2 in the alveoli will increase. At this point, the concentration gradient of O2 will allow it to diffuse from
the alveoli/air to the blood. Meanwhile, the level of CO2 in the blood has Increased due to respiration throughout the body. The concentration gradient of CO2 will allow it to move from the blood to the Alveoli/air. Together, exhalation and inhalation maintain these concentration gradients and the process
is known as ventilation.