Exchange Surfaces

Question 1

What are the key structures of the human gaseous exchange system?

Answer 1

• nasal cavity
• trachea
• ciliated epithelial cells and goblet cels
• bronchi
• bronchioles
• alveoli

Question 2

What are the adaptation of the nasal cavity?

Answer 2

-large surface area it’s good blood supply (warms air as enters)
- hairy surface which secretes mucus
- moist surface

Question 3

What are the adaptations of the trachea

Answer 3

C shaped rings of strong, flexible cartilage (keep it open)

Question 4

What is the function of the ciliated epithelial cells and the goblet cells

Answer 4

Goblet cells produce mucus
Cilia beat rhythmically to move mucus away from lungs

Question 5

What are the adaptations of the bronchioles

Answer 5

No cartilage in walls - instead they contain smooth involuntary muscle
Lined with thin layer of flattened epithelium

Question 6

What are the adaptations of the alveoli

Answer 6

Large surface area
Thin layers - one cell thick
Good blood supply
Good ventilation
Produces lung surfactant (keeps alveoli inflated and allow oxygen to dissolve into it before diffusing into the blood)

Question 8

Describe the process of inhalation

Answer 8

Externa intercostal muscles contract
Rib cage moves up and out
Diaphragm contracts and flattens
Volume of thorax increases
Pressure inside thorax decreases
Air drawn in

Question 9

Describe Boyle’s law during inhalation

Answer 9

The pressure in the lungs is now lower than the pressure outside of the lungs so air enters from this higher pressure

Question 10

Is inhalation an active or passive process

Answer 10

Active

Question 11

Describe the process of exhalation

Answer 11

External intercostal muscles relax
Rib cage moves down and in
Diaphragm relaxes and becomes dome shaped
Volume of thorax decreases
Pressure inside thorax increases
Air is forced out

Question 12

Is exhalation an active or passive process?

Answer 12

Passive

Question 13

What occurs during forced expiration

Answer 13

Internal intercostal muscles contract
Abdominal muscles contact

Question 14

What are the 3 common methods to study the function of the lungs

Answer 14

Peak flow meter
Vitalograph
Spirometer

Question 15

What does the peak flow meter measure and what condition can it be used to assess

Answer 15

Measures the max speed at which a person can exhale air from their lungs
It can assess asthma

Question 16

What is the main lung measurement that the vitalograph measure

Answer 16

Force expiratory volume

Question 17

Give one advantage of using a vitalograph instead of a peak flow meter

Answer 17

Gives a more detailed measurement

Question 18

What are the advantages of a spirometer

Answer 18

More comprehensive measurement
More sensitivity to change
Can assess objective and restrictive lung diseases

Question 19

Define tidal volume

Answer 19

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

Question 20

Define inspiratory reserve volume

Answer 20

The maximum volume of air that can be breathed in over and above a normal inhalation

Question 21

Define expiratory reserve volume

Answer 21

The extra volume of air that you can force out above your normal tidal volume

Question 22

Define residual volume

Answer 22

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

Question 23

Define vital capacity

Answer 23

The volume of air that can be breathed in when the strongest possible exhalation is followed by the deepest possible inhalation

Question 24

Define total lung capacity

Answer 24

The sum of the vital capacity and the residual volume

Question 25

How is ventilation rate calculated

Answer 25

Tidal volume x bpm

Question 26

Give the specific issues associated with living in water

Answer 26

Water is 1000x denser than air Water is 100x more viscous than air Water has a much lower oxygen content than air

Question 27

What are the 2 major adaptations of bony fish

Answer 27

Gills Countercurrent mechanism

Question 28

Describe the structure of the gills

Answer 28

Operculum (bony flap which protects gills and maintains flow of water over gills) Gill arches - arranged in stacks along length of fish Filaments - found in gill arches (also in stacks) Lamellae - main site of gamely exchange in bony fish

Question 29

How do cartilaginous fish maintain a flow of water over their gills

Answer 29

Ram ventilation - continual swimming

Question 30

Describe the process of inspiration in bony fish

Answer 30

Mouth opens and floor of buccal cavity lowers This increase volume and decreases pressure in buccal cavity Water moves into buccal cavity via mouth As pressure in opercular cavity is higher than in buccal cavity, opercular valve closes to stop the backflow of water

Question 31

Describe the process of expiration in bony fish

Answer 31

Mouth and operculum close Sides of opercular cavity move inwards Volume in opercular cavity decreases Pressure in opercular cavity increases Operculum opens and water flows out over the gills

Question 32

Define countercurrent system in terms of bony fish

Answer 32

The water flowing over the gill lamella flows in the opposite direction to the blood flowing through the capillaries in the lamella

Question 33

What is the importance of a countercurrent mechanism

Answer 33

It ensures that a concentration gradient is maintained across the whole length of the exchange system It removes a greater amount of oxygen from the water than concurrent flow

Question 34

Why is it important that insects have adapted a way to deliver oxygen directly to cells and remove CO2

Answer 34

Very active Mainly land dwelling organisms High oxygen demand Tough exoskeleton (barrier to gaseous exchange)

Question 35

What are the adaptations of insects

Answer 35

Spiracles Tracheae lined with chitin Tracheoles Tracheal fluid

Question 36

Describe spiracles

Answer 36

Small openings along abdomen and thorax Allow gases to enter and leave Prevent water loss using their spiracle sphincters Open when demand for O2 increases or CO2 builds up

Question 37

What is chitin

Answer 37

A polysaccharide which prevents the tubes collapsing and is impermeable to gases

Question 38

What are tracheoles

Answer 38

Single, elongated cells with no chitin Where most of the gaseous exchange occurs in insects

Question 39

What happens to oxygen when it arrives in the tracheoles

Answer 39

Dissolves into fluid on the surface of the cells

Question 40

What is the purpose of tracheal fluid in insects

Answer 40

Limits the amount of air that can contribute towards diffusion

Question 41

What are the 2 alternative methods for increasing the level of gaseous exchange in larger insects

Answer 41

Mechanical ventilation - air is actively pumped into tracheal system by muscular contractions of the thorax and the abdomen Collapsible enlarged tracheae or air sacs - act as air reservoirs which can be inflated or deflated by abdominal and thoracic pumping movements