Search results
Results From The WOW.Com Content Network
Sinus node dysfunction also known as sick sinus syndrome is a group of irregular heartbeat conditions caused by faulty electrical signals of the heart. When the heart's sinoatrial node is defective, the heart's rhythms become abnormal—typically too slow or exhibiting pauses in its function or a combination, and very rarely faster than normal ...
Mutations in the intercalated disc gene are responsible for various cardiomyopathies that can lead to heart failure. [2] Ruptured intercalated discs, in this case regarded as a visual artifact. Ruptured intercalated discs, when seen on histopathology, have two main causes: Microtome sectioning, thereby being a visual artifact. [4]
In the nervous system, a synapse [1] is a structure that allows a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or a target effector cell. Synapses can be classified as either chemical or electrical, depending on the mechanism of signal transmission between neurons.
A slow heart rate of 60 or less beats per minute is defined as bradycardia. A fast heart rate of more than 100 beats per minute is defined as tachycardia. An arrhythmia is defined as one that is not physiological such as the lowered heart rate that a trained athlete may naturally have developed; the resting heart rates may be less than 60 bpm.
These signals are propagated through the heart's electrical conduction system. [1] [2] Only one percent of the heart muscle cells are conductive, the rest of the cardiomyocytes are contractile. The pacemaker cells are connected to neighboring contractile cells via gap junctions, which enable them to locally depolarize adjacent cells. Gap ...
An electrical synapse, or gap junction, is a mechanical and electrically conductive synapse, a functional junction between two neighboring neurons. The synapse is formed at a narrow gap between the pre- and postsynaptic neurons known as a gap junction .
Two molecular mechanisms for synaptic plasticity involve the NMDA and AMPA glutamate receptors. Opening of NMDA channels (which relates to the level of cellular depolarization) leads to a rise in post-synaptic Ca 2+ concentration and this has been linked to long-term potentiation, LTP (as well as to protein kinase activation); strong depolarization of the post-synaptic cell completely ...
Action potentials triggered in the baroreceptor ending are then directly conducted to the brainstem where central terminations (synapses) transmit this information to neurons within the solitary nucleus [6] which lies in the medulla. Reflex responses from such baroreceptor activity can trigger increases or decreases in the heart rate.