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Juxtacapillary (J) Receptors
Juxtacapillary receptors, J-receptors, or pulmonary C-fiber receptors are sensory nerve endings located within the alveolar walls in juxtaposition to the pulmonary capillaries of the lung, and are innervated by fibers of the vagus nerve. Although their functional role is unclear, J-receptors respond to events such as pulmonary edema, pulmonary emboli, pneumonia, congestive heart failure and barotrauma, which cause a decrease in oxygenation and thus lead to an increase in respiration. They may be also stimulated by hyperinflation of the lung as well as intravenous or intracardiac administration of chemicals such as capsaicin. The stimulation of the J-receptors causes a reflex increase in breathing rate, and is also thought to be involved in the sensation of dyspnea, the subjective sensation of difficulty breathing. The reflex response that is produced is apnea followed by rapid breathing, bradycardia Bradycardia (also sinus bradycardia) is a slow resting heart rate, commonly unde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Alveolus
A pulmonary alveolus (plural: alveoli, from Latin ''alveolus'', "little cavity"), also known as an air sac or air space, is one of millions of hollow, distensible cup-shaped cavities in the lungs where oxygen is exchanged for carbon dioxide. Alveoli make up the functional tissue of the mammalian lungs known as the lung parenchyma, which takes up 90 percent of the total lung volume. Alveoli are first located in the respiratory bronchioles that mark the beginning of the respiratory zone. They are located sparsely in these bronchioles, line the walls of the alveolar ducts, and are more numerous in the blind-ended alveolar sacs. The acini are the basic units of respiration, with gas exchange taking place in all the alveoli present. The alveolar membrane is the gas exchange surface, surrounded by a network of capillaries. Across the membrane oxygen is diffused into the capillaries and carbon dioxide released from the capillaries into the alveoli to be breathed out. Alveoli are pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vagus Nerve
The vagus nerve, also known as the tenth cranial nerve, cranial nerve X, or simply CN X, is a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It comprises two nerves—the left and right vagus nerves—but they are typically referred to collectively as a single subsystem. The vagus is the longest nerve of the autonomic nervous system in the human body and comprises both sensory and motor fibers. The sensory fibers originate from neurons of the nodose ganglion, whereas the motor fibers come from neurons of the dorsal motor nucleus of the vagus and the nucleus ambiguus. The vagus was also historically called the pneumogastric nerve. Structure Upon leaving the medulla oblongata between the olive and the inferior cerebellar peduncle, the vagus nerve extends through the jugular foramen, then passes into the carotid sheath between the internal carotid artery and the internal jugular vein down to the neck, chest, and abdom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Edema
Pulmonary edema, also known as pulmonary congestion, is excessive edema, liquid accumulation in the parenchyma, tissue and pulmonary alveolus, air spaces (usually alveoli) of the lungs. It leads to impaired gas exchange and may cause hypoxemia and respiratory failure. It is due to either failure of the left ventricle of the heart to remove oxygenated blood adequately from the pulmonary circulation (cardiogenic pulmonary edema), or an injury to the lung parenchyma, lung tissue directly or blood vessels of the lung (non-cardiogenic pulmonary edema). Treatment is focused on three aspects: firstly improving respiratory function, secondly, treating the underlying cause, and thirdly preventing further damage and assuring full recovery to the lung. Pulmonary edema, especially when sudden (acute), can lead to respiratory failure or cardiac arrest due to Hypoxia (medical), hypoxia. It is a cardinal feature of congestive heart failure. The term edema is from the Greek language, Greek (''oi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Emboli
Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream (embolism). Symptoms of a PE may include shortness of breath, chest pain particularly upon breathing in, and coughing up blood. Symptoms of a blood clot in the leg may also be present, such as a red, warm, swollen, and painful leg. Signs of a PE include low blood oxygen levels, rapid breathing, rapid heart rate, and sometimes a mild fever. Severe cases can lead to passing out, abnormally low blood pressure, obstructive shock, and sudden death. PE usually results from a blood clot in the leg that travels to the lung. The risk of blood clots is increased by advanced age, cancer, prolonged bed rest and immobilization, smoking, stroke, long-haul travel over 4 hours, certain genetic conditions, estrogen-based medication, pregnancy, obesity, trauma or bone fracture, and after some types of surgery. A small proportion of cases are du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pneumonia
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity of the condition is variable. Pneumonia is usually caused by infection with viruses or bacteria, and less commonly by other microorganisms. Identifying the responsible pathogen can be difficult. Diagnosis is often based on symptoms and physical examination. Chest X-rays, blood tests, and culture of the sputum may help confirm the diagnosis. The disease may be classified by where it was acquired, such as community- or hospital-acquired or healthcare-associated pneumonia. Risk factors for pneumonia include cystic fibrosis, chronic obstructive pulmonary disease (COPD), sickle cell disease, asthma, diabetes, heart failure, a history of smoking, a poor ability to cough (such as following a stroke), and a weak immune system. Vaccines to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congestive Heart Failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, and leg swelling. The shortness of breath may occur with exertion or while lying down, and may wake people up during the night. Chest pain, including angina, is not usually caused by heart failure, but may occur if the heart failure was caused by a heart attack. The severity of the heart failure is measured by the severity of symptoms during exercise. Other conditions that may have symptoms similar to heart failure include obesity, kidney failure, liver disease, anemia, and thyroid disease. Common causes of heart failure include coronary artery disease, heart attack, high blood pressure, atrial fibrillation, valvular heart disease, excessive alcohol consumption, infection, and cardiomyopathy. These cause heart failure by altering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barotrauma
Barotrauma is physical damage to body tissues caused by a difference in pressure between a gas space inside, or contact with, the body and the surrounding gas or liquid. The initial damage is usually due to over-stretching the tissues in tension or shear, either directly by an expansion of the gas in the closed space or by pressure difference hydrostatically transmitted through the tissue. Tissue rupture may be complicated by the introduction of gas into the local tissue or circulation through the initial trauma site, which can cause blockage of circulation at distant sites or interfere with the normal function of an organ by its presence. Barotrauma generally manifests as sinus or middle ear effects, lung overpressure injuries and injuries resulting from external squeezes. Decompression sickness is indirectly caused by ambient pressure reduction, and tissue damage is caused directly and indirectly by gas bubbles. However, these bubbles form out of supersaturated solution from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Churchill–Cope Reflex
The Churchill–Cope reflex is a reflex in which distension of the pulmonary vascular bed, as occurs in pulmonary edema, causes an increase in respiratory rate (tachypnoea Tachypnea, also spelt tachypnoea, is a respiratory rate greater than normal, resulting in abnormally rapid and shallow breathing. In adult humans at rest, any respiratory rate of 1220 per minute is considered clinically normal, with tachypnea be ...) by stimulation of the juxtacapillary (J) receptors. It was described in 1929 by Edward Delos Churchill and Oliver Cope.Churchill ED, Cope O. The rapid shallow breathing resulting from pulmonary congestion and edema. ''J Exp Med'' 1929; 49:531-537Full text/ref> References Cardiovascular physiology Reflexes {{circulatory-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tachypnea
Tachypnea, also spelt tachypnoea, is a respiratory rate greater than normal, resulting in abnormally rapid and shallow breathing. In adult humans at rest, any respiratory rate of 1220 per minute is considered clinically normal, with tachypnea being any rate above that. Children have significantly higher resting ventilatory rates, which decline rapidly during the first three years of life and then steadily until around 18 years. Tachypnea can be an early indicator of pneumonia and other lung diseases in children, and is often an outcome of a brain injury. Distinction from other breathing terms Different sources produce different classifications for breathing terms. Some of the public describe tachypnea as any rapid breathing. Hyperventilation is then described as increased ventilation of the alveoli (which can occur through increased rate or depth of breathing, or a mix of both) where there is a smaller rise in metabolic carbon dioxide relative to this increase in ventilation. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dyspnea
Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathing, breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity", and recommends evaluating dyspnea by assessing the intensity of its distinct sensations, the degree of distress and discomfort involved, and its burden or impact on the patient's activities of daily living. Distinct sensations include effort/work to breathe, chest tightness or pain, and "air hunger" (the feeling of not enough oxygen). The tripod position is often assumed to be a sign. Dyspnea is a normal symptom of heavy physical exertion but becomes disease, pathological if it occurs in unexpected situations, when resting or during light exertion. In 85% of cases it is due to asthma, pneumonia, cardiac ischemia, interstitial lung disease, congesti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bradycardia
Bradycardia (also sinus bradycardia) is a slow resting heart rate, commonly under 60 beats per minute (BPM) as determined by an electrocardiogram. It is considered to be a normal heart rate during sleep, in young and healthy or elderly adults, and in athletes. In some people, bradycardia below 60 BPM may be associated with fatigue, weakness, dizziness, sweating, and fainting. The term "relative bradycardia" is used to refer to a heart rate slower than an individual's typical resting heart rate. Athletes may have athletic heart syndrome, which includes bradycardia as part of the cardiovascular adaptations to training and participation. The word "bradycardia" is from the Greek βραδύς ''bradys'' "slow", and καρδία ''kardia'' "heart". Classification Sinus Atrial bradycardias are divided into three types. The first, respiratory sinus arrhythmia, is usually found in young and healthy adults. Heart rate increases during inhalation and decreases during exhalation. Thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autar Singh Paintal
Autar Singh Paintal (24 September 1925 – 21 December 2004) was a medical scientist who made pioneering discoveries in the area of neurosciences and respiratory sciences. He is the first Indian Physiologist to become the Fellow of the Royal Society, London. He was a merit student and did his post graduation in physiology from King George Medical College, Lucknow. Paintal completed his PhD under the supervision of David Whitteridge at the University of Edinburgh. His major contribution to the world of science is the development of a single-fiber technique for recording afferent impulses from individual sensory receptors. Paintal discovered several sensory receptors including atrial B receptors, pulmonary J-receptors, ventricular pressure receptors, stomach stretch receptors, and muscle pain receptors. They have set the beginning of new era in physiological understanding. Paintal returned to India in 1953 and joined All India Institute of Medical Sciences, New Delhi. He l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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