What keeps your heart beating?

[Floogeldy]

C'mon! How can it be? Its not like we have a battery, or something. Where's the energy?

Its great, but I don't understand.

[unblock]

1. sinoatrial node

the body's natural pacemaker

http://biology.about.com/library/organs/heart/blsinoatrialnode.htm

[Floogeldy]

4. Yes but where is the power?

What is the energy, the gas, the electricity?

[sir_captain]

5. There is an electrical gradient

made up of sodium, potassium, and calcium ions (all of these are positive to a certain degree.) When enough of an electrical gradient builds up as these ions flow into and out of cells, the gradient passes a threshold and this is called depolarization--this sets off an excitation-contraction coupling process that causes your cardiac muscle to contract in a concerted manner.

[Fridays Child]

14. Individual heart cells are genetically coded to beat. If you separated...

...one from the rest and put it in a lab dish, you could watch it beat on its own. The sinoatrial node is a bundle of tissue that synchronizes all of the randomly beating cells, coordinating the rhythm that pushes blood through the four chambers of the heart.

[0007]

17. 'Tis in the oxygen you breathe

[sir_captain]

2. The sympathetic nervous system

releases norepinephrine onto the sinoatrial and atriaventricular nodes which are located on the outside upper half of your heart, and which are responsible for the electrical excitation that causes your atria and ventricles to contract and pump blood.

[Floogeldy]

6. Norepinephrine

So electricity is the result of a chemical reaction?

Can we power desk lamps in such a manner?

You are obviously a very knowledgeable person and I appreciate your input, sir.

[sir_captain]

9. Well, not exactly

the norepinephrine (which is similar to adrenaline) just causes your heart to beat faster. The heart is unique in the sense that it is autorythmic--it doesn't actually need any input to beat.

But yes, the energy is part of a chemical-electro gradient. It's sort of like a chemical version of a magnet--all chemical ions are either positive or negative, and when a lot of simiarly charged ions build up, this can create a large enough electrical charge to achieve all sorts of things--in this case, the contracting of a portion of the heart.

[Floogeldy]

11. Now that makes sense

Thanks

[sir_captain]

12. No problem

it's not that often that all those science classes actually come in handy ;-)

[HEyHEY]

3. The lust for revenge

[Floogeldy]

7. Ha ha!

:)

[henslee]

10. thats what i was gonna say. Only I really meant it. Not sure if you do.

[hfojvt]

8. we burn carbon - slowly

Ingesting food with protein, carbs and fat, which are all carbon-based providing 4,4,and 9 calories per gram. Inhale oxygen and exhale carbon dioxide. Between meals, we burn stored carbs, or in a pinch, our bodies can cannibalize themselves. In long distance running, when you have burned all of your reserves it is called "hitting the wall".

[JohnnyRingo]

13. Knowing that there's a chance that I may somedget to see the current cabal

...marched out of the White House in 'cuffs.

[soothsayer]

15. I've got pounds and pounds of available energy stored all over

my body. I'm quite clever that way! I notice lots of people on tv and on magazine covers don't have any.

[Magrittes Pipe]

16. Cigarettes, lard, and idleness.

[meganmonkey]

18. Try some of my coffee!

Ooooh, yeah, it gets the heart going every morning!

:hangover: