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  2. Sinoatrial node - Wikipedia

    en.wikipedia.org/wiki/Sinoatrial_node

    The SA node is located in the wall of the right atrium, laterally to the entrance of the superior vena cava in a region called the sinus venarum (hence sino-+ atrial). [5] It is positioned roughly between a groove called the crista terminalis located on the internal surface of the heart and the corresponding sulcus terminalis , on the external ...

  3. Myelin - Wikipedia

    en.wikipedia.org/wiki/Myelin

    Myelin (/ ˈ m aɪ. ə l ɪ n / MY-ə-lin) is a lipid-rich material that surrounds nerve cell axons to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. [1] [2] The myelinated axon can be likened to an electrical wire (the axon) with insulating material (myelin) around it. However ...

  4. Cardiac conduction system - Wikipedia

    en.wikipedia.org/wiki/Cardiac_conduction_system

    Graphical representation of the electrical conduction system of the heart that maintains the heart rate in the cardiac cycle. Electrical signals arising in the SA node (located in the right atrium) stimulate the atria to contract. Then the signals travel to the atrioventricular node (AV node), which is located in the interatrial septum.

  5. Cellular extensions - Wikipedia

    en.wikipedia.org/wiki/Cellular_extensions

    Radial microtubules: They are located in the proximal regions of the ramified processes of oligodendrocytes, that extend outward from the cell body. Lamellar microtubules: They are the microtubules that eventually wrap around the axon, forming the myelin sheath.

  6. Cardiac pacemaker - Wikipedia

    en.wikipedia.org/wiki/Cardiac_pacemaker

    The sinoatrial node (SA node) is the primary pacemaker of the heart. It is a region of cardiac muscle on the wall of the upper right atrium near to the superior vena cava entrance. The cells that make up the SA node are specialized cardiomyocytes known as pacemaker cells that can spontaneously generate cardiac action potentials.

  7. Thoracic wall - Wikipedia

    en.wikipedia.org/wiki/Thoracic_wall

    The bony skeletal part of the thoracic wall is the rib cage, and the rest is made up of muscle, skin, and fasciae.. The chest wall has 10 layers, namely (from superficial to deep) skin (epidermis and dermis), superficial fascia, deep fascia and the invested extrinsic muscles (from the upper limbs), intrinsic muscles associated with the ribs (three layers of intercostal muscles), endothoracic ...

  8. Bundle of His - Wikipedia

    en.wikipedia.org/wiki/Bundle_of_His

    The bundle of His (BH) [1]: 58 or His bundle (HB) [1]: 232 (/ h ɪ s / "hiss" [2]) is a collection of heart muscle cells specialized for electrical conduction.As part of the electrical conduction system of the heart, it transmits the electrical impulses from the atrioventricular node (located between the atria and the ventricles) to the point of the apex of the fascicular branches via the ...

  9. File:Neuron with oligodendrocyte and myelin sheath.svg

    en.wikipedia.org/wiki/File:Neuron_with...

    The following other wikis use this file: Usage on ar.wikipedia.org جهاز عصبي مركزي; ميالين; إعادة تكون الميالين