HSC Biology Marathon 2015 (1 Viewer)

[TQuadded]

Explain how hormone activity maintains water and salt levels in the blood. (5 marks)

Salt and water regulation is maintained with the help of hormones such as aldosterone and anti-diuretic hormones. When water levels in the blood/body is low, osmoreceptors detect this and sends this signal to the brain. The brain recognises the effective method of counteracting this change through releasing anti-diuretic hormones from the hypothalamus. This hormone travels to the kidney in order to make the membrane more permeable to water, increasing the reabsorption of water, and therefore counteracting the low water levels. After the water levels return to normal, the brain halts the production of anti-diuretic hormones.

That's all I can write on my iPhone. My hands are dead, sorry. Someone finish it please. XD

 

[Mr_Kap]

all right then I guess thats it then.

THANKS TO EVERYONE that contibuted to these 21 pages, with their questions and answers. I have no doubt learnt a lot through this thread. Thanks BlueGas for starting this thread and for everyone that has kept it going (especially since trials)..special mentions to BueGas,Flop21,FlyingKanga, Chris_S and DepressedPenguino, Rand_althor and also mentions to TQuadded and tfw english (over the last week), , Khan.Paki, Queenroot, and anyone else i have forgottton. Thx for all the help guys
.

Let's do this guys. LETS SMASH THE EXAM TOMORROW!!!!!!!!!
WE ARE 2015'ers, LETS DO OUR COHORT PROUD!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Watch out bio exam, ure gonna get rekt:

And remember: "What do Biology students do to their notes after the HSC?"
THEY BURNET!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[rand_althor]

Good luck everyone!

 

[rand_althor]

Salt and water regulation is maintained with the help of hormones such as aldosterone and anti-diuretic hormones. When water levels in the blood/body is low, osmoreceptors detect this and sends this signal to the brain. The brain recognises the effective method of counteracting this change through releasing anti-diuretic hormones from the hypothalamus. This hormone travels to the kidney in order to make the membrane more permeable to water, increasing the reabsorption of water, and therefore counteracting the low water levels. After the water levels return to normal, the brain halts the production of anti-diuretic hormones.

That's all I can write on my iPhone. My hands are dead, sorry. Someone finish it please. XD

The hypothalamus doesn't release ADH, it stimulates the pituitary gland to do so. Also be specific in that it acts to increase the permeability of the membranes of cells lining the distal and collecting tubules to water.

For aldosterone: a decrease in sodium ion concentration leads to a decrease in blood volume which causes the adrenal gland to secrete aldosterone. Once aldosterone reaches the kidney, it increases the permeability of the nephron to sodium, particularly in the ascending limb of the Loop of Henle. Sodium ions are thus conserved, which also causes water to be conserved.

 

[Loudvicuna]

The hypothalamus doesn't release ADH, it stimulates the pituitary gland to do so. Also be specific in that it acts to increase the permeability of the membranes of cells lining the distal and collecting tubules to water.

For aldosterone: a decrease in sodium ion concentration leads to a decrease in blood volume which causes the adrenal gland to secrete aldosterone. Once aldosterone reaches the kidney, it increases the permeability of the nephron to sodium, particularly in the ascending limb of the Loop of Henle. Sodium ions are thus conserved, which also causes water to be conserved.

Breh the 2 questions you asked were the exact same in the exam, thanks lol

 

[Flop21]

Not enough differences. You could also mention:
- Blood flows in one direction in arteries, capillaries and veins, whereas phloem sap direction can vary
- Blood moves in different vessels (arteries, capillaries, veins) whereas phloem moves in sieve tubes
- Phloem carries products of photosynthesis whereas blood moves many substances such as carbon dioxide, oxygen etc.

This was in the exam lol, well pretty close to the question in the exam..........

 

[TQuadded]

This was in the exam lol, well pretty close to the question in the exam..........

I put:

- Phloem vs. Blood vessel
- Sugar & water vs. Sugar, water, nitrogenous wastes, carbon dioxide
- Pressure flow theory vs. Pumping of the heart

 

[rand_althor]

Breh the 2 questions you asked were the exact same in the exam, thanks lol

No worries man, was pretty surprised when I saw those.

 

[chairs]

ADH is produced in the hypothalamus and stored in the posterior pituitary

 

[Mazza12]

Could someone please define constant internal environment?

 

[BlueGas]

Could someone please define constant internal environment?

Do you mean homeostasis or what is a body's constant internal environment? This is quite broad as a constant internal environment can consist of many things such as oxygen levels, CO2, blood sugar levels and so on.