If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
Current time:0:00Total duration:7:26

Video transcript

I'm going to draw a person for you this is going to be my side profile this person let's say something like this and this person has I'm going to draw it kind of loosely let's say two arms and one shoulder apparently I need to draw in another shoulder there we go so this is my person and I'm going to draw on their brain this is their brain and they have a heart this is their heart here and now you know there are nerves that come down from the brain and serve the heart right so these are nerves that are basically going to tell the the heart to kind of speed up or heart you know beat harder with higher force of contraction or maybe um relax more quickly so basically what I'm telling you know these are the sympathetic nerves right sympathetic nerves and of course I should also draw in the parasympathetic nerve so these are going to tell the heart to slow down and also going to increase the delay in the AV node and these are the parasympathetic nerves primarily the vagus nerves you might hear that word - vagus nerves and which is basically the actual name of the nerve itself but they are parasympathetic nerves now you have information flowing from the brain down to the heart but you also have information flowing from the heart up to the brain so information is going up as well as down so what would be an example of information going up well you can imagine that there might be volume receptors right so we we know that the brain needs to know about the volume status and in the right atrium there are some volume receptors that basically stretch and once they stretch they tell the brain that there's a you know a lot of blood or if they're not stretched they tell the brain that there's not a lot of blood and this really helps with Auto regulation of blood pressure so if you want to regulate your blood pressure you got to have some information right so auto regulation of blood pressure so basically the whole point of me saying all this is that there's a lot of nerves going back and forth between the brain and the now let's say this person that I'm describing tragically dies they die and they wanted to they later wish was to donate their heart and so over here we have a heart recipient someone that is interested in getting a heart let's say that their heart is not working well or whatever the situation may be they're actually hoping to get a heart so this person is looking for a heart and this person died and their wish was to give a heart so let's let's show that actually let's show the the heart kind of moving over let's say that this person's heart gets sent over to the person on the right so now their heart gets sent over here so all is well right and this person is actually obviously very happy that they got a heart this is a obviously a big deal so this person is now going to let's see if we can do this there we go this person is going to be smiling right and I should probably erase all these little nerves but this brings up a really good point because if the nerves are not coming over right which which they're not it's just the heart then can we regulate all the things that we know that nerves help us regularly can we for example tweak or change the heart rate if needed or can we change the force of contraction if needed or any of those things going to be able to be changed or is this heart basically now kind of always going to be in one status always just kind of beating at one rate you know pumping it with one force is ever going to change is there any way anything can change this now that the nerves are not connected well the first thing is that there are some evidence that nerves can reconnect from the new body but that would take a long long time so in the short term what is the answer well you have a couple of glands right you have adrenal glands sitting here and Audrina just the glass are sitting literally above the kidneys so these are the adrenal glands and you also have thyroid gland so these are the original glands and this is your thyroid up here this is your thyroid kind of in your neck region so these are hormone producers the thyroid gland adrenal glands they're going to be producing hormones and those hormones can affect the heart so one hormone could be for example this would be a sigh roid hormone thyroid hormone down below you might have epinephrine so another hormone number two could be epinephrine this comes from the adrenals so you can see that basically there are hormones are going to affect the heart but you're not getting that rapid over here in the first case when the heart was over here you're getting rapid changes right very very quick but this is going to be a little bit as compared to what we were getting this is going to be a little bit slower a little bit slower in terms of the response rate because you know now the hormone has to go through the bloodstream and get to the heart and you know it takes a little bit of time whereas before with the nerves you're really getting changes as fast as in nerve impulse switches on on the order of less than a second so definitely the response rate is going to be slower so your heart can change it's you know force of contraction and heart rate and conduction velocity it definitely can change in this new person with a with a heart transplant but it will take a little bit longer and another thing that will change it you know in addition to just hormones I want to remind you is medications so let's imagine this person is taking medications and let's say these medications have certain properties let's say they're taking a calcium channel blocker let's say they're taking a medicine that's Accountant I should probably write meds here calcium channel blocker well you know that there are calcium channels in the heart and if you are blocking them then that's going to have an effect on the force of contraction let's say and what if they're taking a beta blocker beta blocker and this is a beta refers to the receptor for F nephron and norepinephrine so if they're taking a beta-blocker they're really blocking the effects of in this case epinephrine right they're blocking epinephrine effects have been Efrain so you can see how if the person starts taking a medication or the stay they take a few pills on a certain day or they're you know adrenal glands are making more epinephrine all these kinds of things are going to essentially change how the heart works how fast it's working how hard it's working so they are going to have changes it's not like they don't have changes in any of those things but those changes are going to take place on a slower time scale than what would have happened in the person who has all the nerves connected