sinotubular junction

(noun)

The sinotubular junction is the point in the ascending aorta where the aortic sinuses end and the aorta becomes a tubular structure.

Related Terms

Examples of sinotubular junction in the following topics:

  • Ascending Aorta

    • The ascending aorta is the first portion of the aorta; it includes the aortic sinuses, the bulb of the aorta, and the sinotubular junction.
    • The aortic root is the portion of the ascending aorta beginning at the aortic annulus, the fibrous attachment between the heart and the aorta, and extending to the sinotubular junction.
    • The sinotubular junction is the point in the ascending aorta where the aortic sinuses end and the aorta becomes a tubular structure.
    • At the junction of the ascending aorta with the aortic arch, the caliber of the vessel increases with a bulging of its right wall.

  • Tight Junctions

    • That zipper is like a tight junction (TJ), also called an occluding junction.
    • This is why tight junctions are also called zonula occludens. 
    • Tight junctions are located within our body’s epithelia. 
    • A tight junction—a kind of symmetrical cell junction—is composed of numerous important proteins that are either directly involved in its composition or intimately involved with connecting the tight junction to and between the cells in one way or another. 
    • An electron micrograph showing a tight junction in rat kidney tissue.

  • Adherens Junctions

    • Adherens junctions are also referred to as zonula adherens, intermediate junction, or as belt desmosomes. 
    • This type of cell junction is located right below tight junctions and provides a strong bond between the sides of adjacent epithelial cell membranes. 
    • While other junctions, like tight junctions, provide some support for and fusion of adjacent cells, their resistance to mechanical stress is relatively small compared to the much stronger adherens junctions. 
    • If you were to remove calcium from the equation, this type of cell junction would disintegrate as a result. 
    • Actin filaments are associated with adherens junctions in addition to several other actin-binding proteins.

  • Gap Junctions

    • A gap junction is a specialized cell junction that directly connects the cytoplasm of two cells.
    • Gap junctions are also called communicating junctions, macula communicans, or nexuses. 
    • The channels in a gap junction aren’t always open. 
    • Gap junctions are found in many places throughout the body. 
    • Intercalated disks consist of three different types of cell–cell junctions: actin filaments anchoring adherens junctions, intermediate filaments anchoring desmosomes, and gap junctions.

  • Peripheral Motor Endings

    • A neuromuscular junction exists between the axon terminal and the motor end plate of a muscle fiber where neurotransmitters are released.
    • A neuromuscular junction is the synapse or junction of the axon terminal of a motor neuron with the motor end plate, as shown in Figures 1 and 2.
    • In vertebrates, the signal passes through the neuromuscular junction via the neurotransmitter acetylcholine.
    • Electron micrograph showing a cross section through the neuromuscular junction.
    • The arrow shows junctional folds with basal lamina.

  • Desmosomes

    • A desmosome is a type of cell junction that attaches to keratin in the cytoplasm and is a localized structure adjoining two cells.
    • A desmosome , also known as macula adherens, is a type of cell junction that attaches to filaments of keratin in the cytoplasm and is characterized by a localized patch that holds two cells tightly together.
    • A type of junctional complex, they are localized spot-like adhesions randomly arranged on the lateral sides of plasma membranes.

  • Esophagus

    • The junction between the esophagus and the stomach (the gastroesophageal junction or GE junction) is not actually considered a valve in the anatomical sense, although it is sometimes called the cardiac sphincter.

  • Microscopic Anatomy

    • Intercalated discs are gap junctions that link cardiomyocytes so that electrical impulses (action potentials) can travel between cells.
    • In a more general sense, an intercalated disk is any junction that links cells together between a gap in which no other cells exist, such as an extracellular matrix.
    • Intercalated discs consist of three types of cell-cell junctions, most of which are found in other tissues besides cardiac muscle:
    • Gap junctions, which connect proteins to the cytoplasm of different cells and transmit action potentials between both cells, required for cellular depolarization.

  • Types of Muscle Tissue

    • The striations are fitted together with unique junctions called intercalated disks, specialized junctions that help in the transmission of electrical impulses so the heart can beat in a steady rhythm.
    • The cells beat in unison as a result of unique gap junctions between the muscle cells.

  • The Synapse

    • A synapse is a structural junction that mediates information transfer from one neuron to the next or from one neuron to an effector cell as in muscle or gland.
    • In an electrical synapse, the presynaptic and postsynaptic cell membranes are connected by special channels called gap junctions that are capable of passing electrical current.
    • These gap junctions contain connexion proteins which allow the ions and small molecules to flow directly from one neuron to the next.