Atrioventricular node

The atrioventricular (AV) node is a part of the electrical conduction system of the heart that coordinates the top of the heart. It electrically connects atrial and ventricular chambers. The AV node is an area of specialized tissue between the atria and the ventricles of the heart, specifically in the posteroinferior region of the interatrial septum near the opening of the coronary sinus, which conducts the normal electrical impulse from the atria to the ventricles. The AV node is quite compact (~1 x 3 x 5 mm). It is located at the center of koch's triangle—a triangle enclosed by the septal leaflet of the tricuspid valve, the coronary sinus, and the membraneous part of the interatrial septum.

Structure

The AV node receives two inputs from the atria: posteriorly, via the crista terminalis, and anteriorly, via the interatrial septum.

Blood supply

The blood supply of the AV node is via the AV nodal artery. The origin of this artery is most commonly (about 90% of hearts) a branch of the right coronary artery, with the remainder originating from the left circumflex artery. This is associated with the dominance of the coronary artery circulation. In right-dominant individuals the blood supply is from the right coronary artery while in left dominant individuals it originates from the left circumflex artery.

Node

In general, a node is a localised swelling (a "knot") or a point of intersection (a vertex).

Node may refer to:

In mathematics

In computing and electronics

Freddie Wong

Freddie Wong (born September 13, 1985) is an American filmmaker, musician, VFX artist and competitive gamer. He is a major part of the YouTube channel RocketJump. He is the older brother of actor and YouTuber Jimmy Wong.

Early life

Wong attended Lakeside School in Seattle, Washington. He then attended and graduated from the University of Southern California School of Cinematic Arts. Wong owns and manages Overcrank Media, a Los Angeles-based media production company specializing in feature film and online video content, having produced an independent film titled Bear. Wong met his future collaborator Brandon Laatsch in college.

Career

Wong competed in the World Series of Video Games in Dallas in July 2007. He won first prize in the Guitar Hero 2 competition, playing the song "Less Talk More Rokk" by Freezepop.

During MTV's "Gamer's Week" celebration in November 2007, Freddie appeared as a guest on Total Request Live. Participating in the program with his newly formed band Hellanor Brozevelt, Wong was part of a country-wide search to find the best Rock Band ensemble. After receiving tutelage from well-known rockers Good Charlotte, Brozevelt performed at the Hard Rock Cafe in New York against Chicago-based Carrie Me Home.

Vertex (graph theory)

In mathematics, and more specifically in graph theory, a vertex (plural vertices) or node is the fundamental unit of which graphs are formed: an undirected graph consists of a set of vertices and a set of edges (unordered pairs of vertices), while a directed graph consists of a set of vertices and a set of arcs (ordered pairs of vertices). In a diagram of a graph, a vertex is usually represented by a circle with a label, and an edge is represented by a line or arrow extending from one vertex to another.

From the point of view of graph theory, vertices are treated as featureless and indivisible objects, although they may have additional structure depending on the application from which the graph arises; for instance, a semantic network is a graph in which the vertices represent concepts or classes of objects.

The two vertices forming an edge are said to be the endpoints of this edge, and the edge is said to be incident to the vertices. A vertex w is said to be adjacent to another vertex v if the graph contains an edge (v,w). The neighborhood of a vertex v is an induced subgraph of the graph, formed by all vertices adjacent to v.