Heart rate Wikipedia. Heart rate is the speed of the heartbeat measured by the number of contractions of the heart per minute bpm. The heart rate can vary according to the bodys physical needs, including the need to absorb oxygen and excrete carbon dioxide. The Same Heart Lyrics' title='The Same Heart Lyrics' />It is usually equal or close to the pulse measured at any peripheral point. Activities that can provoke change include physical exercise, sleep, anxiety, stress, illness, and ingestion of drugs. Many texts cite the normal resting adult human heart rate as ranging from 6. Tachycardia is a fast heart rate, defined as above 1. Bradycardia is a slow heart rate, defined as below 6. Several studies, as well as expert consensus indicates that the normal resting adult heart rate is probably closer to a range between 5. During sleep a slow heartbeat with rates around 4. When the heart is not beating in a regular pattern, this is referred to as an arrhythmia. The Same Heart Woman Riding Dolphin' title='The Same Heart Woman Riding Dolphin' />The Same Heart YoutubeIn addition to their cholesterollowering effects, almonds ability to reduce heart disease risk may also be partly due to the antioxidant action of the vitamin E. Heart of Darkness 1899 is a novella by PolishBritish novelist Joseph Conrad, about a voyage up the Congo River into the Congo Free State, in the heart of Africa. Provide cast, crew, users comments and related links. Award winning Oasis fan site The Site Contains DVD CD Bootleg Artwork, Wallpapers, Latest News, Gigography Discography. Information On Band Members Liam Gallagher. Abnormalities of heart rate sometimes indicate disease. PhysiologyeditWhile heart rhythm is regulated entirely by the sinoatrial node under normal conditions, heart rate is regulated by sympathetic and parasympathetic input to the sinoatrial node. The accelerans nerve provides sympathetic input to the heart by releasing norepinephrine onto the cells of the sinoatrial node SA node, and the vagus nerve provides parasympathetic input to the heart by releasing acetylcholine onto sinoatrial node cells. Therefore, stimulation of the accelerans nerve increases heart rate, while stimulation of the vagus nerve decreases it. Due to individuals having a constant blood volume, one of the physiological ways to deliver more oxygen to an organ is to increase heart rate to permit blood to pass by the organ more often. Normal resting heart rates range from 6. Bradycardia is defined as a resting heart rate below 6. The Same Heart' title='The Same Heart' />Follows the health of an original cohort and two subsequent generations since 1948. What are the symptoms of a heart attack in women The American Heart Association explains how signs of a heart attack in women may be different than heart attack. The Same Heart Nigerian MoviesHowever, heart rates from 5. Tachycardia is defined as a resting heart rate above 1. There are many ways in which the heart rate speeds up or slows down. Most involve stimulant like endorphins and hormones being released in the brain, many of which are those that are forcedenticed out by the ingestion and processing of drugs. This section discusses target heart rates for healthy persons and are inappropriately high for most persons with coronary artery disease. Influences from the central nervous systemeditCardiovascular centreseditThe heart rate is rhythmically generated by the sinoatrial node. It is also influenced by central factors through sympathetic and parasympathetic nerves. Nervous influence over the heartrate is centralized within the two paired cardiovascular centres of the medulla oblongata. The cardioaccelerator regions stimulate activity via sympathetic stimulation of the cardioaccelerator nerves, and the cardioinhibitory centers decrease heart activity via parasympathetic stimulation as one component of the vagus nerve. During rest, both centers provide slight stimulation to the heart, contributing to autonomic tone. This is a similar concept to tone in skeletal muscles. Normally, vagal stimulation predominates as, left unregulated, the SA node would initiate a sinus rhythm of approximately 1. Comic Strip Conversation Templates there. Tomtom Ov2 Files there. Both sympathetic and parasympathetic stimuli flow through the paired cardiac plexus near the base of the heart. The cardioaccelerator center also sends additional fibers, forming the cardiac nerves via sympathetic ganglia the cervical ganglia plus superior thoracic ganglia T1T4 to both the SA and AV nodes, plus additional fibers to the atria and ventricles. The ventricles are more richly innervated by sympathetic fibers than parasympathetic fibers. Sympathetic stimulation causes the release of the neurotransmitter norepinephrine also known as noradrenaline at the neuromuscular junction of the cardiac nerves. This shortens the repolarization period, thus speeding the rate of depolarization and contraction, which results in an increased heartrate. It opens chemical or ligand gated sodium and calcium ion channels, allowing an influx of positively charged ions. Norepinephrine binds to the beta1 receptor. High blood pressure medications are used to block these receptors and so reduce the heart rate. Autonomic Innervation of the Heart Cardioaccelerator and cardioinhibitory areas are components of the paired cardiac centers located in the medulla oblongata of the brain. They innervate the heart via sympathetic cardiac nerves that increase cardiac activity and vagus parasympathetic nerves that slow cardiac activity. Parasympathetic stimulation originates from the cardioinhibitory region with impulses traveling via the vagus nerve cranial nerve X. The vagus nerve sends branches to both the SA and AV nodes, and to portions of both the atria and ventricles. Parasympathetic stimulation releases the neurotransmitter acetylcholine ACh at the neuromuscular junction. ACh slows HR by opening chemical or ligand gated potassium ion channels to slow the rate of spontaneous depolarization, which extends repolarization and increases the time before the next spontaneous depolarization occurs. Without any nervous stimulation, the SA node would establish a sinus rhythm of approximately 1. Since resting rates are considerably less than this, it becomes evident that parasympathetic stimulation normally slows HR. This is similar to an individual driving a car with one foot on the brake pedal. To speed up, one need merely remove ones foot from the brake and let the engine increase speed. In the case of the heart, decreasing parasympathetic stimulation decreases the release of ACh, which allows HR to increase up to approximately 1. Any increases beyond this rate would require sympathetic stimulation. Effects of Parasympathetic and Sympathetic Stimulation on Normal Sinus Rhythm The wave of depolarization in a normal sinus rhythm shows a stable resting HR. Following parasympathetic stimulation, HR slows. Following sympathetic stimulation, HR increases. Input to the cardiovascular centreseditThe cardiovascular centres receive input from a series of visceral receptors with impulses traveling through visceral sensory fibers within the vagus and sympathetic nerves via the cardiac plexus. Among these receptors are various proprioreceptors, baroreceptors, and chemoreceptors, plus stimuli from the limbic system which normally enable the precise regulation of heart function, via cardiac reflexes. Increased physical activity results in increased rates of firing by various proprioreceptors located in muscles, joint capsules, and tendons. The cardiovascular centres monitor these increased rates of firing, suppressing parasympathetic stimulation or increasing sympathetic stimulation as needed in order to increase blood flow. Similarly, baroreceptors are stretch receptors located in the aortic sinus, carotid bodies, the venae cavae, and other locations, including pulmonary vessels and the right side of the heart itself. Rates of firing from the baroreceptors represent blood pressure, level of physical activity, and the relative distribution of blood. The cardiac centers monitor baroreceptor firing to maintain cardiac homeostasis, a mechanism called the baroreceptor reflex. With increased pressure and stretch, the rate of baroreceptor firing increases, and the cardiac centers decrease sympathetic stimulation and increase parasympathetic stimulation.