forgive my spelling i'm lazy

[simpak]

And what exactly do you think is wrong with my paragraph and my grasp of science?

I lol'd for like two minutes - you are the best scientist I know (IN CYBERSPACE).

Also, WHAT THE HELL DUDE, YOU DON'T MAKE THE RULES, THE EXAMINER DOES AND IN THIS CASE THE ASSESSOR SAID SURFACE TO VOLUME RATIO SO ROLE WITH IT.

[simpak]

Oh my god I just spelled 'roll' as 'role'.  I am pro at all things academic.

[cypriottiger]

And what exactly do you think is wrong with my paragraph and my grasp of science?

I lol'd for like two minutes - you are the best scientist I know (IN CYBERSPACE).

Also, WHAT THE HELL DUDE, YOU DON'T MAKE THE RULES, THE EXAMINER DOES AND IN THIS CASE THE ASSESSOR SAID SURFACE TO VOLUME RATIO SO ROLE WITH IT.

but come on he has a point, i mean surface area might be relevant to unit 3 biology but not this semester. im sure any answer that is justified with an appropriate explanation would suffice for the mark

[sillysmile]

And what exactly do you think is wrong with my paragraph and my grasp of science?

I lol'd for like two minutes - you are the best scientist I know (IN CYBERSPACE).

Also, WHAT THE HELL DUDE, YOU DON'T MAKE THE RULES, THE EXAMINER DOES AND IN THIS CASE THE ASSESSOR SAID SURFACE TO VOLUME RATIO SO ROLE WITH IT.

but come on he has a point, i mean surface area might be relevant to unit 3 biology but not this semester. im sure any answer that is justified with an appropriate explanation would suffice for the mark

yeah but this was from a prac exam, so it's not as if this would be part the vcaa exam.

[shinny]

tut tut tut. 

anyways, since this is a bio thread, imma a bit confused about the circulatory system in animals and how it works. Can someone try explaining/summarizing the circulatory system in a succinct manner for me and also about valves and where deoxygenated and oxygenated blood comes from/goes to (and do a better job than my teacher
thanks!

haha, I'm no expert, but here's me trying:
so the heart pumps deoxygenated blood to the lungs,where oxygen binds to the haemoglobin on the red blood cells, this now oxygenated blood travels back to the heart and is pumped throughout the body and the oxygen is transported into the cells where it is used for processes such as cellular respiration. I do realise that was a long sentence and I apologize
okay and the valves are present to prevent blood from flowing backwards in the reverse direction.

so how was that. Btw are you a year 12?

To elaborate, just be aware that there's two circuits. Some basic definitions first though. Arteries pump blood away from the heart. Arteries then lead to capillaries where gas exchange occurs. Veins are what bring the blood back towards the heart.

So basically yeh, there's two systems; the systemic system which pumps oxygenated blood towards capillaries at the tissues to supply the tissues with oxygen (i.e. oxygen diffuses from the blood to the tissue), and the pulmonary system which pumps deoxygenated blood towards the capillaries in the lungs to reoxygenate the blood (i.e. oxygen diffuses from the air in the lungs into the blood). So these two circuits basically form a figure-eight: oxygenated blood gets pumped from the heart to the tissues via systemic arteries, supplies the tissues, drains back as deoxygenated blood into the heart via systemic veins, gets pumped from the heart into the pulmonary arteries into the lungs, picks up oxygen in the lungs and drains back via the pulmonary veins and we're back where we started. Draw it out and you'll get a better idea I guess. So yeh, be aware that the commonly believed 'arteries=oxygenated, veins=deoxygenated blood' thing doesn't actually work. It's flipped in the pulmonary system as you can see.

[simpak]

This thread is so active!  More than one answer is likely to be accepted here but that doesn't mean the STAV response is incorrect or irrelevant.
You are expected to retain knowledge of surface area from unit 3 because it was also studied in units 1 and 2, and is therefore testable on your exam.
It's like expecting not to be tested on addition when you walk into methods 3/4 exams.
Basic knowledge which is to be reapplied again and again.

[HERculina]

haha, I'm no expert, but here's me trying:
so the heart pumps deoxygenated blood to the lungs,where oxygen binds to the haemoglobin on the red blood cells, this now oxygenated blood travels back to the heart and is pumped throughout the body and the oxygen is transported into the cells where it is used for processes such as cellular respiration. I do realise that was a long sentence and I apologize
okay and the valves are present to prevent blood from flowing backwards in the reverse direction.

so how was that. Btw are you a year 12?

To elaborate, just be aware that there's two circuits. Some basic definitions first though. Arteries pump blood away from the heart. Arteries then lead to capillaries where gas exchange occurs. Veins are what bring the blood back towards the heart.

So basically yeh, there's two systems; the systemic system which pumps oxygenated blood towards capillaries at the tissues to supply the tissues with oxygen (i.e. oxygen diffuses from the blood to the tissue), and the pulmonary system which pumps deoxygenated blood towards the capillaries in the lungs to reoxygenate the blood (i.e. oxygen diffuses from the air in the lungs into the blood). So these two circuits basically form a figure-eight: oxygenated blood gets pumped from the heart to the tissues via systemic arteries, supplies the tissues, drains back as deoxygenated blood into the heart via systemic veins, gets pumped from the heart into the pulmonary arteries into the lungs, picks up oxygen in the lungs and drains back via the pulmonary veins and we're back where we started. Draw it out and you'll get a better idea I guess. So yeh, be aware that the commonly believed 'arteries=oxygenated, veins=deoxygenated blood' thing doesn't actually work. It's flipped in the pulmonary system as you can see.

:O wow that was such a good explanation!!!!!! Totally makes sense now you summarized the whole thing into just a paragraph compared to the 10000000000 word uber duba confusing passage from my bio txtbook.
thanks thanks thanks thanks thanks thanks!

sillysmile im yr 10  doing 1/2 bio. i wants a 49 like shinny next year but my SS will probably end up being around 49 -10 = 39 XD

[Russ]

There'll be the obligatory MCQ with "the pulmonary artery carries oxygenated blood from the lungs to the heart" option to trick you

The cardiovascular system is pretty awesome.

[shinny]

There'll be the obligatory MCQ with "the pulmonary artery carries oxygenated blood from the lungs to the heart" option to trick you

The cardiovascular system is pretty awesome.

Yep, definitely favourite system of the body so far. Has a bit of everything really; physiology, biochemistry, anatomy and even physics/maths!

[Russ]

I'm biased towards endocrine, but otherwise CVS is my favourite.

[shinny]

I'm biased towards endocrine, but otherwise CVS is my favourite.

Ahhhh, endocrine cancers are so much fun as well. Big dilemma when it comes to specialising. Hmm.

[HERculina]

There'll be the obligatory MCQ with "the pulmonary artery carries oxygenated blood from the lungs to the heart" option to trick you

The cardiovascular system is pretty awesome.

hmmm. wats the answer to that?
is it an absolute no, cause pulmonary arteries predominately carry deoxygenated blood from the heart to the lungs?
or does it do both :/

[HERculina]

Does doing checkpoints for bio help or would it be a waste of time. 

I gots a question. This time on the digestive system:

The major function of the large intestine is to absorb water. If you were suffering from diarrhoea you would absorb 10 mL of water over 4 hours. If you were suffering from constipation you would absorb 100 mL over 4 hrs. Explain these results. Predict the amount of water you would absorb over 4 hrs if you were not suffering either disease.

[simpak]

Well Checkpoints is filled with VCAA questions so it wouldn't be a waste of time but only do the questions if you have already taken the VCAA exams under exam conditions, because you will spoil them if you do Checkpoints first.

[Russ]

is it an absolute no, cause pulmonary arteries predominately carry deoxygenated blood from the heart to the lungs?
or does it do both :/

Yes, it only carries deoxygenated blood to the lungs (except in utero but that doesn't really count)

The major function of the large intestine is to absorb water. If you were suffering from diarrhoea you would absorb 10 mL of water over 4 hours. If you were suffering from constipation you would absorb 100 mL over 4 hrs. Explain these results. Predict the amount of water you would absorb over 4 hrs if you were not suffering either disease.

If you absorb minimal water (10ml/4hours) then there's a lot of water left in the GIT and it has to be removed from the body somehow (ie diarrhoea).
If you absorb too much water (100ml/4hours) then there's not enough water in the GIT. This causes the faeces to move slowly through the colon/get compacted.

If you weren't suffering either disease...you'd absorb somewhere between those two values. Perhaps 55ml/4hours