There are two groups or clusters of specialized cells that act as the "pacemaker" for the heart. They are modified cardiac myocytes, which is a type of muscle tissue but these don't contract like normal muscle tissue. The Sinoatrial (SA) Node, located at the apex of the right atrium; and the Atrioventricular (AV) Node, located at the base of the right atrium.
The SA Node starts the "heart beat" by sending out an electrical impulse (or action potential) about 60-90 times per minute. The rate can be adjusted by your parasympathetic nervous system, like when you go to sleep; or by your sympathetic nervous system, like when you exercise. Other factors can also deregulate the rate of that action potential, things like: Fatigue, dehydration, alcohol, caffeine, and a number of other chemical imbalances (sodium, potassium, calcium, etc...) So this is just another reason why it's important to eat a well balanced diet, because you can cause your SA Node to go crazy! This impulse from the SA Node causes the left and the right atria to contract simultaneously, sending blood to the ventricles, it also travels along special conduction channels to the AV Node.
The AV Node picks up the impulse from the SA Node where it first delays for about .10s allowing time for the atria to fully eject their blood into the ventricles. Then the AV Node amplifies the signal, for the larger ventricular muscles, and fires its electrical impulse down the His Bundle (specialized nerve/conduction pathways), through the Purkinje fibers (more special nerves) and finally to the ventricular myocardium causing the ventricles to contract.
Then, God willing, the whole thing starts over again.
Pacemaker
btw i got this from my science teacher :) ( . Y . )
The sinoatrial nodes, also known as the pacemakers
Pacemaker
it adjusts the heart rate to correspond to the body's need for oxygen
That would be the speed required to sustain your cells with enough oxygenated blood to allow respiration to happen at the rate your currently reacting at.
Why does exercise change your heart rate? It changes your heart rate with muscle cells by when cells work harder and faster it gives your body more energy which makes you move more. Opposite of when you are asleep you don't move as much. The process cells use to produce energy (ATP) that cells all work together at the same time it creates more energy for your body. Cellular Respiration gets the raw ingredients it needs by when you swallow your food it goes down your esophagus into your digestive system which is part of cellular respiration. The cardiovascular system brings these materials to the cells by digesting the materials into tiny little pieces so it can flow through your body into your cells. My own target and maximum heart rate is one-hundred-and-four to one-hundred-seventy-seven, this is my target zone. My maximum heart rate is two-hundred-seven. You find out your heart rate by deducting your age from two-hundred-twenty-two. Those are MY personal target zones and heart rates. This is why exercise changes your heart rate.do not use this information for any homework background paragraphs because i do not know if it is correct it most likely isn't
when you exercise, your heart rate increases. the more explosive and intense the exercise, the higher the rate will go. As with any muscle in the body, exercise makes it stronger. a stronger heart allows for more blood and oxygen to circulate with each pump resulting in your heart rate lowering not only during exercise but in daily life. a lower heart rate means your heart does not have to work as hard and thats a good thing !!!
Pacemaker cells inside the sinoatrial node in the right atrium spontaneously undergo action potentials at the rate of about 100 beats per minute. While you're alive, innervation from the autonomic system adjusts this rate to suit. These action potentials cause the cardiac muscle to contract, no input from the brain is necessary. As long as the heart muscle has enough energy, oxygen and ions etc that it requires it will continue to beat.
Pacemaker
it adjusts the heart rate to correspond to the body's need for oxygen
Oxygen needs
A pacemaker is a device inserted into the heart to regulate the heart beats or heart rate
the decay rate of carbon is 14 in heart muscle cells,
pacemaker
Calcium has no effect on heart rate. It does, however, have an effect on how hard the heart squeezes (inotropic effect). Heart rate is effected by the slow sodium channels in the pacemaker cells in the right atrium (and other pacemaker cells if the SA node is malfunctioning).
answer it ya self feck head
Sinoatrial Node (SA node)
The pacemaker is only used during a procedure that places an artificial pacemaker in your chest to make your heart beat regular. That is only when the person's heart is having irregular heart beats. People with regular heartbeats with no artificial pacemaker....the way that the heartbeat is regular is through The SA node (sinoatrial). It is a group of cells that is located in the right atrium and sets the pace for the heart, increasing and decreasing when it is needed.
These work by picking up electrical signals that are released when the heart muscle cells contract.
The SA node is the "pacemaker" of the heart. Cells in the SA node are called "pacemaker" cells and they direct the contraction rate of the entire heart by generating action potentials.