a pacemaker that initiated each contraction of a heart beat
"Autorhythmic cells: cardiac or smooth muscle fibers that are self-excitable; act as the heart's pacemaker and conduct the pacing impulse through the conduction system of the heart; self-excitable neurons in central nervous system,as in the inspiratory area of the brain stem." -Principles of Anotomy and physiology, TORTORA, DERRICKSON, 11th edition, Wiley & sons, Inc. (c) 2006 by bio. Sci. textbooks, Inc. and Bryan Derrickson
Medulla Oblongata
working on my circadian rhythmicity
The heart is the only organ containing cardiac muscle
medulla oblongata, in the brain stem.
Christopher John McCabe has written: 'Genetic aspects of rhythmicity in Drosophila melanogaster'
- rhythmicity : capability of rhythmic self-excitation therefore no need for external control -conductivity: conduction of action potential along specialised muscle cells. -excitability: ability of muscle fibers to get exited . -contractility; ability of cardiac muscle to contract . It also has a long refractory period meaning it cant tetanus
Kenneth Clarke Fisher has written: 'Heart rhythmicity of embryo fish. 1. The effect of temperature on te hear rate of trout embryos'
The rhythmicity of breathing is primarily controlled by the brainstem, particularly the medulla oblongata and pons. Neurons in these areas generate rhythmic patterns of activity that regulate the contraction of respiratory muscles. Additionally, sensory input from chemoreceptors and mechanoreceptors helps modulate the rhythm based on the body’s metabolic needs, such as changes in carbon dioxide and oxygen levels. This complex interplay ensures that breathing remains automatic yet adaptable to various physiological demands.
there is a specific group of cells found in the medula (part of the brain stem) which regulate the rhythm of breathing, hence the name (of this cellular formation) the Medulary Rhythmicity Center.
The term referring to cells setting their own rhythm is called "endogenous rhythmicity." This phenomenon describes the ability of cells to generate and maintain their own inherent biological rhythm, such as the circadian rhythm in organisms. This internal clock allows cells to coordinate various physiological processes independently of external cues.
Autorhythmicity is the tendency for the sinoatrial node of the heart to have a low threshold for depolarization leading to the heart contracting on a regular basis, i.e. in a regular rhythm, without external stimulus from the nervous system.
The heart is an involuntary muscle.Involuntary muscles are smooth muscles that are not directly controllable at will. Voluntary muscles are controllable like those found in your arms, legs, hands, etc.