Bethal.Price
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Hey, everyone! Does anyone have an easy way to remember the processes of the heart (in relation to valves, contractions ect and pressure changes), please? And a not so unrelated question: How do you remember the oxygen dissociation curve please?
Many thanks!!
Edit: Yep, am AQA
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EdexcelAreIdiots
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(Original post by Bethal.Price)
Hey, everyone! Does anyone have an easy way to remember the processes of the heart (in relation to valves, contractions ect and pressure changes), please? And a not so unrelated question: How do you remember the oxygen dissociation curve please?
Many thanks!!
Maybe try copying it down from the textbook as a flowchart, then possibly shortening it down to bullet points (maybe with an upwards arrow for increases)?
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brrrigid
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I like to remember it in terms of following the blood, rather than the heart itself. Bear in mind this is AQA content - you didn't say what exam board you are with, but AQA has all the content you've listed so I'm going to assume we have the same. Hope you don't mind all the detail I went into! Used this post as an excuse for some revision.

heart cycle
Spoiler:
Show



ventricles relax; atria contract
We start in the atria. To move the blood into the ventricles, the atria contract - so the atrioventricular valves must be open. Because the atria are contracting, their pressure must increase while their volume decreases. The blood is moving from atria into the ventricles, so there will be a slight increase in both pressure and volume inside the ventricles.

ventricles contract; atria relax
Now the blood is in the ventricles, so the atria are relaxing. The ventricles contract - ensuring the pressure of the ventricles > atria. The atrioventricular valves must then close, preventing the back-flow of blood. Blood now moves from the ventricles into the aorta and pulmonary artery, which means the semi-lunar valves are open; and for the SL valves to be open, the pressure in the arteries must be lower than that in the ventricles.

ventricles relax; atria relax
The blood is now in the pulmonary artery and the aorta. The ventricles relax, and the atria are still relaxed. The semi-luar valves close due to the higher pressure in the arteries, preventing back-flow of blood into the ventricles. Blood begins to return to the heart, entering into the atria - so the pressure of the atria increase, which when combined with the still falling pressure of the ventricles, opens the atrioventricular valves, allowing the passive movement of blood into the ventricles from the atria. The atria then contract, and the process repeats.

-> I remember this in terms of the movement of blood, by drawing out a simple heart diagram and using arrows to essentially 'move' through the heart.



dissociation curves
Spoiler:
Show


If you remember the shape of the oxygen dissociation curve - an 'S' - you can easily work other bits of information out. At the bottom and the top of the S, it is harder for oxygen to bond to haemoglobin - but in the middle, the S is very flat and increases in value quickly, which is where oxygen can bind to haemoglobin much more easily.

Animals with high affinity haemoglobin have a dissociation curve that is shifted slightly to the left of a human one, as they need to be able to load O2 at lower O2 partial pressures. So, animals with high oxygen affinity often live in low oxygen environments.

Animals with low affinity haemoglobin have a dissociation curve that is shifted slightly to the right of a human one, which allows them to unload O2 much more easily. So, animals with low oxygen affinity often have high activity levels, or have high metabolic rates.

But you will need to remember the Bohr effect when evaluating dissociation curve data, which describes the effect of CO2 partial pressure.



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EdexcelAreIdiots
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(Original post by brrrigid)
I like to remember it in terms of following the blood, rather than the heart itself. Bear in mind this is AQA content - you didn't say what exam board you are with, but AQA has all the content you've listed so I'm going to assume we have the same. Hope you don't mind all the detail I went into! Used this post as an excuse for some revision.

heart cycle
Spoiler:
Show




ventricles relax; atria contract
We start in the atria. To move the blood into the ventricles, the atria contract - so the atrioventricular valves must be open. Because the atria are contracting, their pressure must decrease while their volume decreases. The blood is moving from atria into the ventricles, so there will be a slight increase in both pressure and volume inside the ventricles.

ventricles contract; atria relax
Now the blood is in the ventricles, so the atria are relaxing. The ventricles contract - ensuring the pressure of the ventricles > atria. The atrioventricular valves must then close, preventing the back-flow of blood. Blood now moves from the ventricles into the aorta and pulmonary artery, which means the semi-lunar valves are open; and for the SL valves to be open, the pressure in the arteries must be lower than that in the ventricles.

ventricles relax; atria relax
The blood is now in the pulmonary artery and the aorta. The ventricles relax, and the atria are still relaxed. The semi-luar valves close due to the higher pressure in the arteries, preventing back-flow of blood into the ventricles. Blood begins to return to the heart, entering into the atria - so the pressure of the atria increase, which when combined with the still falling pressure of the ventricles, opens the atrioventricular valves, allowing the passive movement of blood into the ventricles from the atria. The atria then contract, and the process repeats.

-> I remember this in terms of the movement of blood, by drawing out a simple heart diagram and using arrows to essentially 'move' through the heart.




dissociation curves
Spoiler:
Show



If you remember the shape of the oxygen dissociation curve - an 'S' - you can easily work other bits of information out. At the bottom and the top of the S, it is harder for oxygen to bond to haemoglobin - but in the middle, the S is very flat and increases in value quickly, which is where oxygen can bind to haemoglobin much more easily.

Animals with high affinity haemoglobin have a dissociation curve that is shifted slightly to the left of a human one, as they need to be able to load O2 at lower O2 partial pressures. So, animals with high oxygen affinity often live in low oxygen environments.

Animals with low affinity haemoglobin have a dissociation curve that is shifted slightly to the right of a human one, which allows them to unload O2 much more easily. So, animals with low oxygen affinity often have high activity levels, or have high metabolic rates.

But you will need to remember the Bohr effect when evaluating dissociation curve data, which describes the effect of CO2 partial pressure.




Nicely put, how do you revise Biology (AQA for me too)? Have you tried the 2017 paper? I feel like I fully revised but I only just scraped an A.
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brrrigid
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(Original post by EdexcelAreIdiots)
Nicely put, how do you revise Biology (AQA for me too)? Have you tried the 2017 paper? I feel like I fully revised but I only just scraped an A.
Thankyou - and I tend to just go through loads of questions, and if I find I can't recall enough about a topic, I'll revise that topic within the same day. I also use flashcards a lot, though more so for chem.

Yeah, I went through the 2017 - one thing that always trips me up is the wording. So so specific for AQA
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redonks
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(Original post by brrrigid)
I like to remember it in terms of following the blood, rather than the heart itself. Bear in mind this is AQA content - you didn't say what exam board you are with, but AQA has all the content you've listed so I'm going to assume we have the same. Hope you don't mind all the detail I went into! Used this post as an excuse for some revision.

heart cycle
Spoiler:
Show




ventricles relax; atria contract
We start in the atria. To move the blood into the ventricles, the atria contract - so the atrioventricular valves must be open. Because the atria are contracting, their pressure must increase while their volume decreases. The blood is moving from atria into the ventricles, so there will be a slight increase in both pressure and volume inside the ventricles.

ventricles contract; atria relax
Now the blood is in the ventricles, so the atria are relaxing. The ventricles contract - ensuring the pressure of the ventricles > atria. The atrioventricular valves must then close, preventing the back-flow of blood. Blood now moves from the ventricles into the aorta and pulmonary artery, which means the semi-lunar valves are open; and for the SL valves to be open, the pressure in the arteries must be lower than that in the ventricles.

ventricles relax; atria relax
The blood is now in the pulmonary artery and the aorta. The ventricles relax, and the atria are still relaxed. The semi-luar valves close due to the higher pressure in the arteries, preventing back-flow of blood into the ventricles. Blood begins to return to the heart, entering into the atria - so the pressure of the atria increase, which when combined with the still falling pressure of the ventricles, opens the atrioventricular valves, allowing the passive movement of blood into the ventricles from the atria. The atria then contract, and the process repeats.

-> I remember this in terms of the movement of blood, by drawing out a simple heart diagram and using arrows to essentially 'move' through the heart.




dissociation curves
Spoiler:
Show



If you remember the shape of the oxygen dissociation curve - an 'S' - you can easily work other bits of information out. At the bottom and the top of the S, it is harder for oxygen to bond to haemoglobin - but in the middle, the S is very flat and increases in value quickly, which is where oxygen can bind to haemoglobin much more easily.

Animals with high affinity haemoglobin have a dissociation curve that is shifted slightly to the left of a human one, as they need to be able to load O2 at lower O2 partial pressures. So, animals with high oxygen affinity often live in low oxygen environments.

Animals with low affinity haemoglobin have a dissociation curve that is shifted slightly to the right of a human one, which allows them to unload O2 much more easily. So, animals with low oxygen affinity often have high activity levels, or have high metabolic rates.

But you will need to remember the Bohr effect when evaluating dissociation curve data, which describes the effect of CO2 partial pressure.




you are a hero among civilians. a god among men.
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brrrigid
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(Original post by redonks)
you are a hero among civilians. a god among men.
but you! are my wife! :gfight:
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Bethal.Price
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(Original post by brrrigid)
I like to remember it in terms of following the blood, rather than the heart itself. Bear in mind this is AQA content - you didn't say what exam board you are with, but AQA has all the content you've listed so I'm going to assume we have the same. Hope you don't mind all the detail I went into! Used this post as an excuse for some revision.

heart cycle
Spoiler:
Show




ventricles relax; atria contract
We start in the atria. To move the blood into the ventricles, the atria contract - so the atrioventricular valves must be open. Because the atria are contracting, their pressure must increase while their volume decreases. The blood is moving from atria into the ventricles, so there will be a slight increase in both pressure and volume inside the ventricles.

ventricles contract; atria relax
Now the blood is in the ventricles, so the atria are relaxing. The ventricles contract - ensuring the pressure of the ventricles > atria. The atrioventricular valves must then close, preventing the back-flow of blood. Blood now moves from the ventricles into the aorta and pulmonary artery, which means the semi-lunar valves are open; and for the SL valves to be open, the pressure in the arteries must be lower than that in the ventricles.

ventricles relax; atria relax
The blood is now in the pulmonary artery and the aorta. The ventricles relax, and the atria are still relaxed. The semi-luar valves close due to the higher pressure in the arteries, preventing back-flow of blood into the ventricles. Blood begins to return to the heart, entering into the atria - so the pressure of the atria increase, which when combined with the still falling pressure of the ventricles, opens the atrioventricular valves, allowing the passive movement of blood into the ventricles from the atria. The atria then contract, and the process repeats.

-> I remember this in terms of the movement of blood, by drawing out a simple heart diagram and using arrows to essentially 'move' through the heart.




dissociation curves
Spoiler:
Show



If you remember the shape of the oxygen dissociation curve - an 'S' - you can easily work other bits of information out. At the bottom and the top of the S, it is harder for oxygen to bond to haemoglobin - but in the middle, the S is very flat and increases in value quickly, which is where oxygen can bind to haemoglobin much more easily.

Animals with high affinity haemoglobin have a dissociation curve that is shifted slightly to the left of a human one, as they need to be able to load O2 at lower O2 partial pressures. So, animals with high oxygen affinity often live in low oxygen environments.

Animals with low affinity haemoglobin have a dissociation curve that is shifted slightly to the right of a human one, which allows them to unload O2 much more easily. So, animals with low oxygen affinity often have high activity levels, or have high metabolic rates.

But you will need to remember the Bohr effect when evaluating dissociation curve data, which describes the effect of CO2 partial pressure.




What a hero, thank you so much!!!
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