Gas Exchange

Question 1

Name two features of a gas exchange surface

Answer 1

Thin- short diffusion distance

Large surface area

Question 2

Name two adaption of gills for gas exchange

Answer 2

Llamella give large surface area

Counter current flow maintains conc gradient

Question 3

What do hairs do

Answer 3

Trap water vapour

Question 4

why do single celled organisms not need specialised exchange surfaces?

Answer 4

as the substances can diffuse directly in or out of the organism due to a short diffusion distance

Question 5

outline the order of the structures in the respiratory system

Answer 5

Trachea —> bronchi —> bronchioles —> alveolar ducts —> alveoli

Question 6

how does the alveoli structure maximise gas exchange?

Answer 6

there are many alveoli
-so large surface area
they are one cell thick
-so short diffusion distance

Question 7

Describe how oxygen from the air in the alveolus enters the blood

Answer 7

Diffuses across the capillary epithelium and the capillary endothelium into the blood

Question 8

why is breathing out difficult in fibrosis

Answer 8

as there is Loss of elasticity

so Less recoil of alveoli

Question 9

outline the process of inspiration

Answer 9

Diaphragm contracts and moves down 
External intercostal muscles contract
 ribs move up and out.
Volume increases, pressure decreases
Air moves in down pressure gradient

Question 10

what is different in forced expiration from regular expiration

Answer 10

the internal intercostal muscles contract

Question 11

outline the process of expiration

Answer 11

Diaphragm relaxes and moves up
External intercostal muscles relax 
ribs move down and in
Volume decreases, pressure increases
Air moves out down pressure gradient

Question 12

what is tidal volume

Answer 12

The volume of air moved in/out of lungs with each breath

Question 13

what do gill fillaments provide?

Answer 13

a large surface area for exchange of gases

Question 14

what do lamellae do to gill fillaments

Answer 14

further increase the surface area for gas exchange

Question 15

explain the advantage of the one way flow of water over the gills

Answer 15

it needs less energy

Question 16

what do tracheoles provide

Answer 16

a short diffusion pathway for oxygen to directly diffuse into a body cell

Question 17

how do gases diffuse into insects down a diffusion gradient

Answer 17

oxygen used up in respiration creating diffusion gradient for oxygen diffuses into cells from atmosphere down trachea down tracheoles
carbon dioxide produced in respiration so it diffuses out of cells out of tracheoles and out trachea

Question 18

how do insects move air in and out of the spiracles

Answer 18

insects use rythmic abdominal movements to move air in and out of the spiracles

Question 19

where does gas exchange occur in an insect

Answer 19

between gas in the tracheole and the tracheal fluid

Question 20

what can insects do to their tracheal fluid to increase surface area for gas exchange

Answer 20

they can retract their tracheal fluid to increase surface area for gas exchange

Question 21

what are the pores on an insects body called

Answer 21

spiracles it is where gases enter and leave the insect

Question 22

why do small organisms not have specialised exchange surfaces

Answer 22

as they have a large enough surface area
compared to their volume
to allow effcient exchange to occur

Question 23

how do insects reduce water loss

Answer 23

by closing their spiracles
waterproof waxy cuticle around their body
tiny hairs near spiracles which both reduce evaporation