Gas Exchange

?
  • Created by: Zammi10
  • Created on: 28-03-17 10:05
What factors can increase the rate of diffusion?
A thin wall/short diffusion distance. Moist to allow oxygen to dissolve. Large surface area. Permeable. High concentration gradient
1 of 43
How does gas exchange occur in unicellular organisms?
Gas exchange on unicellular organisms occurs across their surface membrane as they have a large surface area : volume ratio, therefore this is efficient enough for gas exchange
2 of 43
What does the build up of carbon dioxide in respiring unicellular organisms do?
sets up a concentration gradient so that the gas diffuses out of the cell. If the organism respires aerobically then oxygen diffuses down a concentration gradient into the cell as the oxygen is used up.
3 of 43
What is the surface membrane of unicellular organsisms like?
Thin and moist.
4 of 43
How do multicellular organisms undergo gas exchange?
Via specialised gas exchange surfaces usually
5 of 43
Maintaining a concentration gradient for gases is a problem that large organisms face because diffusion becomes less efficient over larger distance. How do multicellular organisms overcome such problems?
Transport systems (e.g. circulatory systems) are needed to ensure that dissolved gases can move to and from respiring tissues rapidly.
6 of 43
What sort of special adaptation can terrestrial organisms have?
internal gas exchange surfaces to reduce evaporation losses.
7 of 43
Many small terrestrial animals use their outer body surfaces efficiently for gas exchange. The earthworm, Lumbricus terrestris, achieves this with:
An elongated body to increase the surface area:volume ratio. Primitive circulatory system to maintain a concentration gradient. A moist outer body surface.
8 of 43
The outer body surface of the earthworm is supplied with what?
A dense capillary network which join up to form contractile blood vessels
9 of 43
How does the earthworm increase the efficiency of diffusion without a heart?
the circulatory system transports oxygen to and carbon dioxide away from respiring tissues, thereby increasing the efficiency of diffusion.
10 of 43
What else do Earthworms do?
They secrete mucus to maintain a moist surface and they have a well developed capillary network under the skin
11 of 43
What about their metabolic rate?
Low metabolic rate to reduce oxygen requirements.
12 of 43
They have a network of what?
Blood vessels and blood containing haemoglobin for the transport of oxygen
13 of 43
How is carbon dioxide transported?
Largely in the blood plasma.
14 of 43
How are flatworms adapted?
They have a flattened body to reduce the diffusion distance between the surface and the cells inside and to increase the overall surface area
15 of 43
How are amphibians such as frogs and newts adapted?
They have moist, permeable skin with a well developed capillary network beneath the surface. They also have lungs that are used when more active
16 of 43
Reptiles such as snakes and crocodiles?
These have internal lungs like amphibians but these are more complex and have a larger surface area
17 of 43
Birds- flight does what?
Generate a very high metabolic rate and hence oxygen requirement. T
18 of 43
To meet this, what do birds have?
They have an efficient ventilation mechanism to increase the concentration gradient across the lung surface.
19 of 43
Gas exchange in fish
Whoop Woop
20 of 43
What do fish have?
Fish have developed a specialised internal gas exchange surface called gills
21 of 43
What are gills made up of?
Numerous gill filaments contains gill lamellar at right angles to the filaments.
22 of 43
What do these lamallea do?
They increase the surface area for the exchange of oxygen and carbon dioxide.
23 of 43
What are examples of cartilaginous fish?
Sharks
24 of 43
How do they ventilate their gills?
Blood and water flow in the same direction over the gill i.e. Parallel flow
25 of 43
where is gas exchange only possible and why?
It is only possible over part of the gill filament surface as an equilibrium is eventually reached which prevents further diffusion and reduces the oxygen that can be absorbed into the blood
26 of 43
What happens when equilibrium is reached?
It prevents further diffusion and reduces the oxygen that can be absorbed into the blood
27 of 43
What is the ventilation mechanism like in cartilagenous fish?
It is basic, as they swim they open their mouth and allowing water to pass over the gills.
28 of 43
What happens as they swim?
They open their mouth allowing water to pass over gills
29 of 43
What are examples of bony fish?
Salmon, haddock etc. all the tasty ones
30 of 43
What type of ventilation and what happens
Counter current flow so that water and blood pass over the gills in opposite directions. Blood with the highest O2 conc. meets water with highest O2 conc. therefore equilibrium is never reached. Higher oxygen absorption and more efficient/
31 of 43
Why do fish die out of water?
Because air is not a dense enough medium to keep the gills open. Out of water, the gills collapse and the filaments stick together greatly reducing the surface area for absorption of water.
32 of 43
What sort of skeleton do bony fish have?
They have an internal bony skeleton and a flap covering the gills called operculum.
33 of 43
Gas exchange in insects...
...
34 of 43
What do the tracheae look like in insects
Branched, chitin lined system of tracheae with openings called spiracles.
35 of 43
How is the chitin arranged?
It is arranged into rings, which allows the trachea to expand and contract and act like belllows drawing air in and out of the insect's body
36 of 43
Where are the spiracles found?
Found in pairs on segments of the thorax and abdomen.When can they close?
37 of 43
When can they close?
During periods of inactivity and the presence of chitin helps to reduce water loss
38 of 43
Tracheae tribes do what?
Come into direct contact with every tissue, supplying oxygen and removing carbon dioxide , so there is no need for haemoglobin
39 of 43
What are the ends of the tubes filled with and why?
They are filled with fluid to allow gases to dissolve.
40 of 43
What do muscles in the thorax and abdomen do?
They contract/relax causing rhythmical movements that ventilate the tracheal tubes, maintaining a concentration gradient.
41 of 43
What do insects ave and what is the significance of this?
Have an exoskeleton of chitin covered in wax, this is impermeable to water and gases
42 of 43
The efficiency of tracheal system is supplying oxygen to tissues list insect size and...
Shape as it relies upon diffusion, which is dependent upon diffusion.
43 of 43

Other cards in this set

Card 2

Front

Gas exchange on unicellular organisms occurs across their surface membrane as they have a large surface area : volume ratio, therefore this is efficient enough for gas exchange

Back

How does gas exchange occur in unicellular organisms?

Card 3

Front

sets up a concentration gradient so that the gas diffuses out of the cell. If the organism respires aerobically then oxygen diffuses down a concentration gradient into the cell as the oxygen is used up.

Back

Preview of the back of card 3

Card 4

Front

Thin and moist.

Back

Preview of the back of card 4

Card 5

Front

Via specialised gas exchange surfaces usually

Back

Preview of the back of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

BIOL 2
See all Biology resources »See all Gas Exchange resources »