Which ion is responsible for slow channel action potential?
calcium ions
The secondary inward current that flows through the slow channel is probably carried primarily by calcium ions. This current is responsible, in part, for the plateau phase of the cardiac action potential.
Which ion is most responsible for depolarization of conductive myocardium?
Potassium channels As the membrane potential becomes more positive (i.e. during cell stimulation from a neighbouring cell), the flow of potassium into the cell via the Kir decreases. Therefore, Kir is responsible for maintaining the resting membrane potential and initiating the depolarization phase.
Which wave on the electrocardiogram ECG represents ventricular depolarization?
The QRS complex
The QRS complex represents ventricular depolarization. Ventricular rate can be calculated by determining the time interval between QRS complexes.
Why is ischemic myocardium depolarized?
Because this pump is electrogenic, it normally produces hyperpolarizing currents. Decreased activity, therefore, leads to depolarization because of the loss of hyperpolarizing currents.
What is the difference between ligand-gated and voltage-gated?
The key difference between voltage gated and ligand gated ion channels is that the voltage gated ion channels open in response to a voltage difference while the ligand gated channels open in response to a ligand binding. Membrane transport is an important mechanism that allows ions to enter and release the cell.
What is the difference between a gated ion channel and a leak channel?
Leak channels, also called passive channels, are always open, allowing the passage of sodium ions (Na ) and potassium ions (K ) across the membrane to maintain the resting membrane potential of –70 millivolts. Voltage-gated ion channels open and close in response to specific changes in the membrane potential.
What are the key differences between a cardiac action potential and the action potential of a neuron?
One major difference is in the duration of the action potentials. In a typical nerve, the action potential duration is about 1 ms. In skeletal muscle cells, the action potential duration is approximately 2-5 ms. In contrast, the duration of cardiac action potentials ranges from 200 to 400 ms.
Is QRS depolarization or repolarization?
QRS complex (ventricular depolarization) The QRS complex represents ventricular depolarization. Ventricular rate can be calculated by determining the time interval between QRS complexes. Click here to see how ventricular rate is calculated. The duration of the QRS complex is normally 0.06 to 0.10 seconds.
How does ECG determine ischemia?
The most common ECG sign of myocardial ischemia is flat or down-sloping ST-segment depression of 1.0 mm or greater. This report draws attention to other much less common, but possibly equally important, ECG manifestations of myocardial ischemia.
How is an ECG used to diagnose heart problems?
The signals are shown as waves on an attached computer monitor or printout. An ECG can show if the heart is beating too slow, too fast or not at all. An electrocardiogram records the electrical signals in your heart. It’s a common and painless test used to quickly detect heart problems and monitor your heart’s health.
What is the difference between ECG and EKG?
ECG and EKG tests are the same. A healthcare professional will perform an EKG to help diagnose certain heart conditions. EKGs are quick, painless tests. An EKG usually takes around 3 minutes to…
What are the risks of the electrocardiogram (ECG)?
There is no risk of electrical shock during the test because the electrodes used do not produce electricity. The electrodes only record the electrical activity of your heart. You may have minor discomfort, similar to removing a bandage, when the electrodes are removed.
Can a normal ECG show an abnormal rhythm?
A standard ECG can record an abnormal heart rhythm only if it happens during the test. Some abnormal heart rhythms come and go, so your doctor may have you undergo a different type of heart rhythm monitoring, such as with a Holter monitor, to help diagnose the cause of your symptoms.