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As the electrical activity is spreading throughout the atria, it travels via specialized pathways, known as internodal tracts, from the SA node to the AV node.
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What will happen if hyperkalemia occurs in the electrical synapse of the SA node?
During generation of action potential, sodium and calcium ions enter from extracellular fluid to intracellular fluid. Depolarisation occurs and SA node gets stimulated. But due to more potassium ions in the synapse(outside the cell) k+ ions can't move out of the neuron to cause repolarisation of the cell membrane. So, the membrane remains in a depolarised state and the cardiac muscles remain contracted.
What the location of the SA node?
The Sinoatrial (SA) node and the Atrioventricular (AV) node are both extremely important in the conduction events of the heart. The Sinoatrial node displays pacemaker activity - that is, it spontaneously depolarizes, setting in forth the chain of events that is required for contraction of the heart. Depolarization refers to the event in which positive ions flow into the heart, resulting in a voltage change in the heart, leading to contraction. From the SA node, the voltage is conducted through the internodal pathway to the AV node, in which the impulse is temporarily paused before been transmitted through the Bundle of His and the Left and Right bundle branches. These events, as previously mentioned, are extremely important in conduction pathways of the heart, and hence, the function of the heart :)
The point on a stem to which a leaf or bud is attached is termed the?
the node, leaves are attached to the node by the petiole
What is a twig juncture?
A twig juncture is called a node.
Do neurotransmitters affect SA node?
SA node effects which neurotransmitter?
Depolarization of the sa node occurs during?
P wave
What pacemaker of the heart initiates depolarization under normal conditions?
The primary pacemaker of the mammalian heart is the sino-atrial node. If the SA node fails, the atrioventricular node (AV node) takes over pacemaking.
The crescent-shaped pacemaker of the heart that initiates depolarization under normal conditions is the?
Sinoatrial node
The p wave of the electrocardiogram is a signal from?
The P wave on ECG corresponds to electrical depolarization of the atria. It should be positive in lead II and negative in aVR when the P wave originates in the sinoatrial node.
Immediately before the P wave?
The electrical milestone event that occurs at the P wave of the cardiac cycle of the EKG is atrial depolarization. The upward stroke is right atrial depolarization, and the downward stroke is left atrial depolarization. Normally, this lasts for no more than 0.11 sec.
When threshold is reached at the SA node what channels open causing further depolarization of the membrane?
Fast Calcium
What does a ventricular pacemaker do to initiate a heartbeat?
The SA node (Sinoatrial node) sets the pace for the heart as a whole because no other region of the conduction system or the myocardium has a faster depolarization rate. For this reason, it is the heart's pacemaker.
What generates the p wave of an electrocardiogram?
A P wave denotes atrial depolarization or when your atriacontracts. It is generated by the Sinoatrial (SA) node which is the primary pacemaker and signifies a Sinus Rhythm.
What is sinus arrest?
When the Sino-atrial node fails momentarily to initiate an impulse, sinus arrest occurs. When the sino-atrial node fails momentarily to initiate an impulse, sinus arrest occurs.
When does saltatory conduction occur?
Saltatory Conduction is a means by which action potentials are transmitted along myelinated nerve fibers. The cytoplasm of an axon is electrically conduction and because myelin inhibits charge leakage through the membrane, depolarization at one node of Ranvier is sufficient to elevate the voltage at a neighboring node to the threshold for action potential initiation. Therefore in myelinated axons, instead of axon propagating as waves but they occur at successive nodes and 'hop' along the axon. This means of travel is much faster than they would otherwise (120 m/sec compared to 35m/sec in unmyelinated nerve fibers). Another advantage of this is that energy is saved as sodium potassium pumps are only required at specific points along the axon. Sean Sinclair
Why is an action potential is self-regenerating?
The Na+ diffusing into the axon during the first phase of the action potential creates a depolarizing current that brings the next segment, or node, of the axon to threshold.
Why is an action potential self-regenerating?
The Na+ diffusing into the axon during the first phase of the action potential creates a depolarizing current that brings the next segment, or node, of the axon to threshold.
