The sinoatrial node, abbreviated SA node, is the natural pacemaker. The SA node is a specialized collection of cells in the right atrium that can depolarize autonomously and do so on a regular basis. It is a bundle of neurons which 'fire' an electrical impulse at regular intervals, causing the heart muscle to contract. After the sinoatrial node has fired, the electrical impulse is sent to other nodes within the heart which then fire in a sequence that produces the heart beat.
Sinoatrial node, SA Node
An orifice is a natural opening.
Pharmaology
Pacemaker.
The medical term for "without teeth" is edentulous.edentulousThe word "edentulous" means being without natural teeth.That would be toothless. or it is endentulous without natural teeth.The medical term for "without teeth" is edentulous.toothless
Endorphins
The medical term for without a lens is aphakia. This condition occurs when the natural lens of the eye is either absent or surgically removed.
Syncope is the medical term meaning fainting.
Anacusis is the medical term meaning complete deafness.
Lamina is the medical term meaning layers.
Sensation is the medical term meaning feeling.
Eructation is the medical term meaning burping.eructation
Kyphotic is the medical term meaning humpbacked.