Senior Science Discussion Thread

[Ragdolls]

Hi. I just wanted to ask if someone could please explain to me how the sinoatrial node (or natural pacemaker) works [its function in the heart]. I also wanted to ask how electrocardiograms work in terms of what is occurring at each part of the graph (P,Q,R,S,T) in the heart.

Syllabus point:
- explain that specialised tissues in the heart produce an electrical signal that stimulates rhythmic contractions of the cardiac muscle

Thank you.

[studybuddy7777]

Hi Ragdolls! Thanks for joining atarnotes! Its great youre posting questions!
(I just lost all of this work that I was just about to post so bear with me if i cut things short)

Lets start with the ECG.
I'll use the terms depolarisation (meaning contracting/contraction) and repolarisation (meaning relaxing/relaxation) as these are the terminology that youll be wanting to use in your response to wow the marker
Point P represents the contraction (depolarisation) of the atria (note: plural of atrium, they are in sync)
Points Q, R and S (QRS complex) represents the simultaneous depolarisation of the ventricles and the repolarisation of the atria. It is important to note how fast this complex works. Anything considers above 0.11 seconds is considered abnormal, with 0.08-0.09 seconds considered average.
Point T represents the repolarisation of the ventricles
Point U (I only put this in as it is in some textbooks and so you might get a question on it, but I wouldnt exactly stress this) is simply the resting stage between points P and U, where neither atrium or ventricle is depolarisating or repolarising.

I'll post this before I lose it again and i hope this helps

[Ragdolls]

Hi Ragdolls! Thanks for joining atarnotes! Its great youre posting questions!
(I just lost all of this work that I was just about to post so bear with me if i cut things short)

Lets start with the ECG.
I'll use the terms depolarisation (meaning contracting/contraction) and repolarisation (meaning relaxing/relaxation) as these are the terminology that youll be wanting to use in your response to wow the marker
Point P represents the contraction (depolarisation) of the atria (note: plural of atrium, they are in sync)
Points Q, R and S (QRS complex) represents the simultaneous depolarisation of the ventricles and the repolarisation of the atria. It is important to note how fast this complex works. Anything considers above 0.11 seconds is considered abnormal, with 0.08-0.09 seconds considered average.
Point T represents the repolarisation of the ventricles
Point U (I only put this in as it is in some textbooks and so you might get a question on it, but I wouldnt exactly stress this) is simply the resting stage between points P and U, where neither atrium or ventricle is depolarisating or repolarising.

I'll post this before I lose it again and i hope this helps

Thank you studybuddy7777

[studybuddy7777]

No probs ragdoll enjoy

Are you ok with the SA node? It basically works by sending rhythmic electrical impulses to the heart. Its basically there to keep your heart pumping around blood which if, as you know didnt happen, your cells would lyse suffer from 'malnutrition' (idk proper term lol) and you would die.

If you need any greater depth of knowledge feel free to ask me or drop me a msg. Either one is totally fine

[Ragdolls]

No probs ragdoll enjoy

Are you ok with the SA node? It basically works by sending rhythmic electrical impulses to the heart. Its basically there to keep your heart pumping around blood which if, as you know didnt happen, your cells would lyse suffer from 'malnutrition' (idk proper term lol) and you would die.

If you need any greater depth of knowledge feel free to ask me or drop me a msg. Either one is totally fine

Thank you Studybuddy7777. Yes I'm good with the SA node but the explanation was good anyways. thank you. I will ask if i need help. 

[studybuddy7777]

Thanks and thats good because its what I (and essentially all of AN) is here for

[studybuddy7777]

Just putting it out there if you install an app called Tiny Cards (ios has it, android not sure) by Duolingo (the language company yes) you'll see if you search for senior science my glossary on flash cards. 80+ definitions so is certainly worth a look!! Going to put up biology and studies of religion as well for my everyone's gain

Thanks all and feel free to ask any questions, queries, comments, criticisms or the like that you may have!

[vincentso69]

Hey jnicko, sure!

The best way I can show this to you is through a diagram, so one should be attached.
The electrocardiogram is quite simply defined as a test which tests the electrical activity of the heart (eg the ventricular and aortic valves) to detect problems. It is the typical wave that comes out of the monitor that you see everywhere (like the one that beeps on TV when the patient is alive and flatlines when there is no pulse ).
It is important to note however, a "beat" is from P to P, and not from P to T (some textbooks/sources use a "U" as resting time as well but most don't- just putting it out there)

Hope this helps otherwise feel free to ask

wow this is very useful. I have tried to understand what the lumps ment for so long and this simple diagram is just so easily understood

[AngelicOnyx]

Just wondering, but if a question asks for how visible light is used in information systems, could you talk about how we use it for vision? Or is it limited to optical fibres (some of my notes are conflicting)

[studybuddy7777]

Just wondering, but if a question asks for how visible light is used in information systems, could you talk about how we use it for vision? Or is it limited to optical fibres (some of my notes are conflicting)

Hey AngelicOnyx, sorry for the delay.

Visible light is used in Information Systems. So while you could talk about how we use it for vision, I don't recommend it as vision is a very limited communication. You don't just have to just limit it to optical fibres however.

Actually for vision, you could go on the path of talking about non-verbal communications (eg billboards, smoke signals, posters, mail etc) as vision is needed for it, but don't go talking about how are eyes are important because we see out of them. Sorry if I'm conflicting as well but I'm doing my best and information systems isn't my best topic.

EDIT: Also dont forget that infra-red can be classified under visible light so the use of laser beams and all that could also be brought in to the discussion.

[RuiAce]

EDIT: Also dont forget that infra-red can be classified under visible light

Wait what?

[studybuddy7777]

Wait what?

Technically speaking infra-red can be classified under visible light as you can see laser beams shining. Hence it is a form of communication. The same cannot be said for ultraviolet light simply because you cannot see it.

Just obviously remember it is a different wavelength to visible light

[RuiAce]

Technically speaking infra-red can be classified under visible light as you can see laser beams shining. Hence it is a form of communication. The same cannot be said for ultraviolet light simply because you cannot see it.

Just obviously remember it is a different wavelength to visible light

I thought that red light was just because it emits a bit of red light as well. Not it was also IR.

[studybuddy7777]

I thought that red light was just because it emits a bit of red light as well. Not it was also IR.

I'm having trouble following. Infrared light emits red light yes. Red light that we can see. Hence it can be used as a visual communication. Not ideal in my opinion, but the option is there.

[RuiAce]

I'm having trouble following. Infrared light emits red light yes. Red light that we can see. Hence it can be used as a visual communication. Not ideal in my opinion, but the option is there.

Well that's really just utilising the red light that gets emitted alongside IR in my opinion.