episode46

046 How Adrenaline and Acetylcholine Affect Heart Rate

In this episode, Leslie discusses the effect of adrenaline and acetylcholine on heart rate. These two modifies the conductance of the ions across the membranes of the cells of the SA node causing either an increase or a decrease in heart rate.

Watch and learn how it all works.

Enjoy!

Transcript of Today’s Episode

Hello and welcome to another episode of Interactive Biology TV where we’re making Biology fun. My name is Leslie Samuel and in this episode, Episode 46, I’m going to talk about how adrenaline and acetylcholine affect heart rate. So, let’s get right into it.

In the last episode, Episode 45, we looked at this slide where I showed that in the SA node, we have a pacemaker potential that results in a spontaneous signal so that we have the heart beating in response to these action potentials that are automatically generated in the SA node.

If you haven’t looked at Episode 45, I would recommend for you to pause this right now and go and watch Episode 45 so that you’re going to get a full understanding of what we’re going to be talking about.

Let’s go to the next slide. I’m sure you’ve all been in situations where, let’s say you’re doing something and someone jumps up behind you and scares you. What happens? Your heart starts beating faster. The reason it starts beating faster is because adrenaline is released from the adrenal gland that’s located above the kidneys. When that adrenaline is released, that causes the conductance in the pacemaker cells to change. As you can see here, we have an increased conductance for sodium and calcium ions. That is going to cause those to rush into the cell much faster.

It’s going to look a little different than what we looked at before because the membrane potential is going to increase significantly faster so that we’re going to get a faster action potential. So, it might look something like this. As you can see, the signal happens much faster. Forgive my sloppy drawing here. So, we have signals being produced much faster and the heart rate increases. If you remember from the last one that I showed, I was able to show two action potentials on this. But, because sodium and calcium ions are rushing in much faster, the signals are going to be generated much faster because it’s going to reach the threshold much faster and we get an increased heart rate. So, that’s adrenaline.

Now, there’s an opposite effect where instead of adrenaline being released, we have acetylcholine being released. I didn’t plan for the acetylcholine to come in as a flame but, it did for some reason.

What happens when acetylcholine is released? As you can see up here, the conductance for potassium is going to increase significantly. You should know that potassium wants to leave the cell. So, this is going to increase hyperpolarization and is going to slow down depolarization.

What’s going to happen is, instead of this rapid depolarization, we’re going to get a significantly slower depolarization so that, it takes much longer to reach the threshold. When it reaches the threshold, the usual process happens: voltage-gated calcium channels open and calcium rushes in to the cell. Then, we have our depolarization. Then, this process continues.

But, as you can see here, depolarization is much slower than over here. Here, depolarization is sped up because sodium and calcium are rushing into the cell much faster in response to adrenaline. Here, it’s going to be much slower because more potassium is leaving the cell causing depolarization to slow down and we get a slower heart rate.

Faster heart rate in response to adrenaline; slower heart rate in response to acetylcholine.

That’s pretty much it for this video. As usual, you can visit the website at Interactive-Biology.com for more Biology videos and all of the other resources we’re putting together over there. This is Leslie Samuel. That’s it for this video and I’ll see you on the next one.

86 comments
aishwarya
aishwarya

This was really helpful...thank you vry much.

CuttlefishPi
CuttlefishPi

I think it has to do with the sympathetic and pathetic nervous systems, or with the amount of CO2 in the blood. Google it.

sanket patil
sanket patil

hey but why adreline and acetylcholine released in heart

sanket patil
sanket patil

but why adrenaline and acetylcholine comes inheart

Marcela Martinez
Marcela Martinez

I watch at least one of your videos randomly before I go to sleep,.

richaisdbest
richaisdbest

Hi...i have a question...dosent hyperpolarisation occur beyond the RMP ?? In the depiction the hyperpolarisation was not shown or i am lacking some concept here..please correct me if i am wrong...on the whole a very nice video!

richaisdbest
richaisdbest

Thanks a lot.You make it so easy...Keep up the good work!

Alexsh2010
Alexsh2010

This was really really helpful! Thanks!

Sasidhar Mittapalli
Sasidhar Mittapalli

Thank you that was just perfect explanation i was looking for. You din't mention when acetlycholine will be released?

Coddey Dave
Coddey Dave

i got bullied once,adreneline pumped and i beat the crap out of those guys

Parastoo HR
Parastoo HR

it's released for example when your're sleeping!

Naomi
Naomi

THanks Lesley. This is really hwlpful for understanding basic physiology. Keep in going.

Justin Wong
Justin Wong

I wish my lecturers provide much more interesting classes, like you do. God bless you Leslie, thank you :) Worth subscribing.

Justin Nicholai
Justin Nicholai

I wish my lecturers provide much more interesting classes, like you do. God bless you Leslie, thank you :) Worth subscribing.

SamGuthrie1977
SamGuthrie1977

Thanks! Great video -- this is exactly what I was looking for concerning Acetylcholine's effects on heart rate.

SamGuthrie1977
SamGuthrie1977

Thanks! Great video -- this is exactly what I was looking for concerning Acetylcholine's effects on heart rate.

abrara321
abrara321

gd job my teacher . i have a question , you said that adrenaline released when we get scary, what about acetylcholine what causes it to be released ? ?

abrara321
abrara321

gd job my teacher . i have a question , you said that adrenaline released when we get scary, what about acetylcholine what causes it to be released ? ?

ardruma
ardruma

Where is the plateau phase?

ardruma
ardruma

Where is the plateau phase?

mortdepeur13
mortdepeur13

i remember all the adrenaline i had when i was getting panic attacks. but they are not dangerous ;) the sensation is very scary and you think you are dying everytime when you freak out. But when you have fun with the fear it feels awesome and you feel like powerful. its hard to explain lol

mortdepeur13
mortdepeur13

i remember all the adrenaline i had when i was getting panic attacks. but they are not dangerous ;) the sensation is very scary and you think you are dying everytime when you freak out. But when you have fun with the fear it feels awesome and you feel like powerful. its hard to explain lol

InteractiveBiology
InteractiveBiology

Glad this helped a lot :) We have more Biology videos in our website just in case you need more help. Stay tuned!

KurikuShot
KurikuShot

Thank you very much for this video. I'm doing a question on how Adrenaline increase heart rate but all the books I read merely state that it does and doesn't explain it. This is exactly what I'm looking for and in extremely comprehensive terms too!

InteractiveBiology
InteractiveBiology

@KurikuShot Glad this helped a lot :) We have more Biology videos in our website just in case you need more help. Stay tuned!

InteractiveBiology
InteractiveBiology

@KurikuShot Glad this helped a lot :) We have more Biology videos in our website just in case you need more help. Stay tuned!

InteractiveBiology
InteractiveBiology

Glad this helped a lot :) We have more Biology videos in our website just in case you need more help. Stay tuned!

KurikuShot
KurikuShot

Thank you very much for this video. I'm doing a question on how Adrenaline increase heart rate but all the books I read merely state that it does and doesn't explain it. This is exactly what I'm looking for and in extremely comprehensive terms too!

KurikuShot
KurikuShot

Thank you very much for this video. I'm doing a question on how Adrenaline increase heart rate but all the books I read merely state that it does and doesn't explain it. This is exactly what I'm looking for and in extremely comprehensive terms too!

KurikuShot
KurikuShot

Thank you very much for this video. I'm doing a question on how Adrenaline increase heart rate but all the books I read merely state that it does and doesn't explain it. This is exactly what I'm looking for and in extremely comprehensive terms too!

KurikuShot
KurikuShot

Thank you very much for this video. I'm doing a question on how Adrenaline increase heart rate but all the books I read merely state that it does and doesn't explain it. This is exactly what I'm looking for and in extremely comprehensive terms too!

Elsabicton
Elsabicton

please make some videos on all body system

Elsabicton
Elsabicton

please make some videos on all body system

Elsabicton
Elsabicton

please make some videos on all body system

InteractiveBiology
InteractiveBiology

Thank you sir. Glad to know you are finding value in the content. Stay tuned for many more videos :)

johny2481
johny2481

wonderfully explained sir hats of very clear and excellent physiology explanation

InteractiveBiology
InteractiveBiology

@johny2481 Thank you sir. Glad to know you are finding value in the content. Stay tuned for many more videos :)

InteractiveBiology
InteractiveBiology

@johny2481 Thank you sir. Glad to know you are finding value in the content. Stay tuned for many more videos :)

InteractiveBiology
InteractiveBiology

Thank you sir. Glad to know you are finding value in the content. Stay tuned for many more videos :)

johny2481
johny2481

wonderfully explained sir hats of very clear and excellent physiology explanation

johny2481
johny2481

wonderfully explained sir hats of very clear and excellent physiology explanation

johny2481
johny2481

wonderfully explained sir hats of very clear and excellent physiology explanation

johny2481
johny2481

wonderfully explained sir hats of very clear and excellent physiology explanation

Estrellita Calaro
Estrellita Calaro

How does high serum calcium affects heartbeat? How about high serum potassium? Pls explain. I understand that calcium released by sarcoplasmic reticulum produced contraction of of the heart muscle but I do not understand how extracellular calcium and/or extracellular potassium affects heartbeat. Pls explain. Thanks.

Lrsamuel
Lrsamuel

Excess Potassium levels would decrease the heart rate because that's going to slow down depolarization in the SA node. Check out my video that deals with the SA node and you'll see how Potassium is involved in determining heart rate.

Excess extracellular calcium will result in spastic contraction of the heart, because of how Calcium is involved in contraction. Check out the video on the Contraction of the Heart.

Hope that helps!

Estrellita Calaro
Estrellita Calaro

How does high serum calcium affects heartbeat? How about high serum potassium? Pls explain. I understand that calcium released by sarcoplasmic reticulum produced contraction of of the heart muscle but I do not understand how extracellular calcium and/or extracellular potassium affects heartbeat. Pls explain. Thanks.

Lrsamuel
Lrsamuel

Excess Potassium levels would decrease the heart rate because that's going to slow down depolarization in the SA node. Check out my video that deals with the SA node and you'll see how Potassium is involved in determining heart rate. Excess extracellular calcium will result in spastic contraction of the heart, because of how Calcium is involved in contraction. Check out the video on the Contraction of the Heart. Hope that helps!