Why conserving H2O important? This info is not needed in the first part of the paper A higher blood pressure is maintained throughout due to constant pumping of the heart, with the fast delivery of oxygen and nutrients to the tissues. The herbivores diet of mostly carbohydrates has a low energy yield; this is ok for the herbivore however because of the low energy required and the accessibility of the diet. The animals with such system have high percentage of body that is fluid.

When the operculum opens, the water flows from the buccal cavity, across the gills and into the opercular cavity from high to low pressure and then exits. They do not rely on their outer body surface for gas exchange but have specialized internal gas exchange surfaces, called lungs, which have the following features: The mucus holds a film of water and thus prevents desiccation of the animals to some extent. An earthworm is small enough that the skin is a sufficient gas exchange organism; No Also, the way the cow regurgitates its food means that the partially digested cellulose is brought back into mouth for mastication, which further increases SA, thus further increasing microbe fermentation efficiency. The alveoli lie close to the capillaries and are the site of gas exchange in humans.

Hi euaznboy Diagrams are a good option Could be written as A counter current system allows water and blood to flow in opposite directions which means there is always a concentration gradient in place for oxygen to move into the blood.

A higher blood pressure is maintained throughout due to constant pumping of the heart, with the fast delivery of oxygen and nutrients to the tissues. While the points you make are correct they are common sense and are not at a gaa 12 biology level so would not help you get merit or excellence. The blood moves around the body within the vessels. FISH Gills are membranous stuctures that are folded in order to provide a large surface area for gas exchange, the extraction of oxygen from water by ncfa.



Hi STs, I’m not trying to sound impatient The trachea also has cilia, small extensions of the skin that beat upwards to remove dust and other particles.

Could someone take a look at my gas exchange essay?

They have thin membranes so they have a high surface area to volume ratio. Discussion The circulatory system of insects, fish and mammals are different according their suitability.

Gas Exchange – WGHS BAP Year 12

And btw, i was just wondering, how many adaptations do u need to gs about in the exam? Im doing fish, mammal and insect gas exchange. Heamolymph is the name of the liquid insects use to transport substances. Herbivores have to eat all the time to sustain themselves on the low energy diet, and the material they eat is not digested very efficiently.

ncea gas exchange essay

Trachea branch to become very thin tracheoles that end in a small fluid sac beside a body cell. Diversity in the gas exchange systems of fish, insects and humans is related to differences in the terrestrial and aquatic environments.

We have taken many students through the steps of comparing the three groups for plants and animals – happy reading Once you’ve put something together we are more than happy to go from there Cheers ST The rings of chitin provide support for the trachea and the tracheoles have a high surface area to maximise diffusion. Cows — repetition of the info given above is not helpful……discussion needs to focus on the differences in the cows digestive system as a result of the grass diet that they do not produce the enzymes to digest!

Again insufficient info to make the point. Unlike humans and insects, they move slowly and therefore do not require a large amount of oxygen.


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Also the discussion needs to have more ‘biological’ reasons for the diversity ie differences. I am becoming increasingly confused when I read the responses the science teachers are giving in regards to exchangd essays.

Mammals In humans gas exchange occurs as such: However because there is no circulatory system the tracheae system restricts insects to a very small size. My other paragraphs are about: The counter current system means that water and blood are flowing in opposite directions across the gill lamellae, therefore the gradient is always such that the water has more available oxygen than the blood. Is this all correct?

ncea gas exchange essay

I like reading them! The two bronchi divide into bronchioles, which further divide into air sacs called alveoli.

By structures I mean the way the animal is adapted to achieve a gas exchange surface with a large surface area, moist, thin and maintain a concentration gradient. I’m working on improvements now.

ncea gas exchange essay

Blood is pumped through a two chambered heart and travels around the body where its passes through the gill to be oxygenated but as this occurs the blood loses pressures.

Enzymes are not added by the cow until the food reaches the Abomasum where HCl and enzymes work together to create an acidic environment for the cow to chemically digest microbes to gain amino acids.

The sizes of the gas exchange systems of these three animals differs according to their body size and metabolic rate. Unlike worms and fish, mammals moistly live in a drying environment, so their gas exchange system, the lungs, is hidden deep in the body.