Ventilation And Gas Exchange In The Lungs

Question 1

Nasal cavity key structure

Answer 1

• Large surface area and great blood supply
  -hairy lining
  -moist surfaces

Question 2

Key structure trachea

Answer 2

• The pipe is supported by a layer of cartilage that holds the trachea open and prevents it from collapsing.
• The rings are Incomplete to allow it to the bend when food is swallowed down the oesophagus behind.
• The trachea is lined with ciliated epithelial and goblet cells that prevent dust and bacteria from entering

Question 3

Key structure bronchus

Answer 3

• The bronchus are extensions of the trachea that split into two for the left and right lung
• this was a very similar structure to the trachea but smaller
• cartilage rings hold the pip open

Question 4

Key structure bronchioles

Answer 4

• The bronchus split into much smaller bronchioles this are about 1mm or less in diameter they have not cartilage and are held open by smoothen muscle when this muscle contract the bronchioles contract this dependant on air flow

Question 5

Lung surfactant

Answer 5

This is a phospholipid that coats the surface of the lungs without it, the watery lining of the alveoli would create a surface tension, which could cause them to collapse.

Question 6

Feature of efficient gas exchange

Answer 6

-large surface area
- thin layer
- blood supply
- ventilation

Question 7

Key structure alveoli

Answer 7

• The alveoli are little air sacs, this is where most of the gas exchange occurs
• they are made of a thin layer of flattened epithelial cells, as well as some collagen and elastic fibres
• The elastic fibres cause recoil which helps move air out of the alveoli

Question 8

Function of goblet cells

Answer 8

The walls of the trachea und bronchus contain goblet cells, which secrete mucus made of mucin this traps micro-organism and debris helping to keep the airways clear

Question 9

Inspiration

Answer 9

This is an energy using (active) process
- diaphragm - moves down
-Intercostal muscles - move up and out
- thoracic volume - increase
- thoracic pressure - decreases
-Air flow in to lung (to equalise the pressure difference)

Question 10

Expiration

Answer 10

This is a largely passive process:
Diaphragm moves up, intercostal muscles move down and in, thoracic volume decreases, thoracic pressure increases, air flow out the lungs (to equalise the pressure difference )

Question 11

Inspiratory reserve volume

Answer 11

The maximum volume of air you can breathe in over and above normal inhalation

Question 12

Expiratory reserve volume

Answer 12

Maximum volume of air you can force out of your lungs over and above the normal tidal volume of air you breathe out

Question 13

Tidal volume

Answer 13

The volume of air that moves into and out of the lungs with each resting breath

Question 14

Vital capacity

Answer 14

The largest volume of air that can be breathed in

Question 15

Residual volume

Answer 15

The volume of air that ‘s left in your lungs when you have exhaled as hard as possible

Question 16

Total lung capacity

Answer 16

Total lung capacity = residual volume+ vital capacity

Question 17

Gas exchange

Answer 17

Mouth → trachea → bronchus → bronchiole → alveoli