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85-445: Breathing ( spiration or ventilation ) is the rhythmical process of moving air into ( inhalation ) and out of ( exhalation ) the lungs to facilitate gas exchange with the internal environment , mostly to flush out carbon dioxide and bring in oxygen . All aerobic creatures need oxygen for cellular respiration , which extracts energy from the reaction of oxygen with molecules derived from food and produces carbon dioxide as

170-453: A waste product . Breathing, or external respiration, brings air into the lungs where gas exchange takes place in the alveoli through diffusion . The body's circulatory system transports these gases to and from the cells, where cellular respiration takes place. The breathing of all vertebrates with lungs consists of repetitive cycles of inhalation and exhalation through a highly branched system of tubes or airways which lead from

255-436: A century. It seemed logical that the rehearsal of learned information during the day, such as in dreams, could be responsible for this consolidation. REM sleep was first studied in 1953. It was thought to be the sole contributor to memory due to its association with dreams. It has recently been suggested that if sleep and waking experience are found to be using the same neuronal content, it is reasonable to say that all sleep has

340-477: A consequent rise in the pH of the arterial plasma leading to respiratory alkalosis . This is one contributor to high altitude sickness . On the other hand, if the switch to oxygen homeostasis is incomplete, then hypoxia may complicate the clinical picture with potentially fatal results. Pressure increases with the depth of water at the rate of about one atmosphere – slightly more than 100 kPa, or one bar , for every 10 meters. Air breathed underwater by divers

425-620: A correlation between athletic performance and circadian timing. It has been shown certain times of the day are better for training and gametime performance. Training has the best results when done in the morning, while it is better to play a game at night. The ability to perceive and generate music is frequently studied as a way to further understand human rhythmic processing. Research projects, such as Brain Beats, are currently studying this by developing beat tracking algorithms and designing experimental protocols to analyze human rhythmic processing. This

510-495: A day" in Latin. This refers to the human 24-hour cycle of sleep and wakefulness. This cycle is driven by light. The human body must photoentrain or synchronize itself with light in order to make this happen. The rod cells are the photoreceptor cells in the retina capable of sensing light. However, they are not what sets the biological clock. The photosensitive retinal ganglion cells contain a pigment called melanopsin . This photopigment

595-437: A deep breath or adopt a deeper breathing pattern. Neuroscience of rhythm The autonomic nervous system is responsible for many of the regulatory processes that sustain human life. Autonomic regulation is involuntary, meaning we do not have to think about it for it to take place. A great deal of these are dependent upon a certain rhythm, such as sleep, heart rate, and breathing. Circadian literally translates to "about

680-539: A demand for more oxygen, as for example by exercise. The terms hypoventilation and hyperventilation also refer to shallow breathing and fast and deep breathing respectively, but under inappropriate circumstances or disease. However, this distinction (between, for instance, hyperpnea and hyperventilation) is not always adhered to, so that these terms are frequently used interchangeably. A range of breath tests can be used to diagnose diseases such as dietary intolerances. A rhinomanometer uses acoustic technology to examine

765-439: A difference as possible, which results in the learning of the song. Dr. Sober believes that this is also the mechanism employed in human speech learning. Although it's clear that humans are constantly adjusting their speech while birds are believed to have crystallized their song upon reaching adulthood. He tested this idea by using headphones to alter a Bengalese finch's auditory feedback. The bird actually corrected for up to 40% of

850-406: A healthy brain to be studied. Also, pharmacological manipulation, cell culture imaging and computational biology all make attempts at doing this but in the end they are indirect. The classification of frequency borders allowed for a meaningful taxonomy capable of describing brain rhythms, known as neural oscillations . Functional residual capacity Functional residual capacity ( FRC )

935-430: A lower FRC in the supine position due to the added tissue weight opposing the outward recoil of the chest wall thus reducing chest wall compliance. In pregnancy, this starts at about the fifth month and reaches 10-20% decrease at term. FRC tends to increase with aging due to changes in the static recoil of the lungs. The predicted value of FRC was measured for large populations and published in several references. FRC

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1020-415: A normal mammal, the lungs cannot be emptied completely. In an adult human, there is always still at least one liter of residual air left in the lungs after maximum exhalation. Diaphragmatic breathing causes the abdomen to rhythmically bulge out and fall back. It is, therefore, often referred to as "abdominal breathing". These terms are often used interchangeably because they describe the same action. When

1105-468: A part in consolidation as well as REM sleep. There have even been studies done implying that sleep can lead to insight or creativity. Jan Born, from the University of Lubeck, showed subjects a number series with a hidden rule. She allowed one group to sleep for three hours, while the other group stayed awake. The awake group showed no progress, while most of the group that was allowed to sleep was able to solve

1190-431: A position called the "resting position", which is determined by their anatomical elasticity. At this point the lungs contain the functional residual capacity of air, which, in the adult human, has a volume of about 2.5–3.0 liters. During heavy breathing ( hyperpnea ) as, for instance, during exercise, exhalation is brought about by relaxation of all the muscles of inhalation, (in the same way as at rest), but, in addition,

1275-457: A precision grip task, it was seen that the disruption of the PTN resulted in a greatly reduced oscillatory response. Stimulation of the PTN caused the monkeys to not be able to perform the grip task as well. It was concluded that PTNs in the motor cortex directly influence the generation of Beta rhythms. At the moment, recording methods are not capable of simultaneously measuring small and large areas at

1360-557: A precision grip task. More specifically, the pyramidal tract neurons (PTNs) were targeted for measurement. The primary frequency recorded was between 15 and 30 Hz, the same oscillation found in humans. These findings indicate that the macaque monkey cortex could be a good model for rhythm perception and production. One example of how this model is used is the investigation of the role of motor cortex PTNs in " corticomuscular coherence " (muscle coordination). In similar study where LFPs were recorded from macaque monkeys while they performed

1445-404: A role in memory consolidation. This is supported by the rhythmic behavior of the brain. Harmonic oscillators have the capability to reproduce a perturbation that happened in previous cycles. It follows that when the brain is unperturbed, such as during sleep, it is in essence rehearsing the perturbations of the day. Recent studies have confirmed that off-wave states, such as slow-wave sleep , play

1530-412: A sustained level of oxygen in the blood by triggering the lungs to expand and contract at the correct time. This was seen by the measuring of action potentials. It was observed that certain groups of neurons synchronized with certain phases of respiration. The overall behavior was oscillatory in nature. This is an example of how an autonomous biorhythm can control a crucial bodily function. This refers to

1615-464: A tendency to occur with certain moods. Due to this relationship, practitioners of various disciplines consider that they can encourage the occurrence of a particular mood by adopting the breathing pattern that it most commonly occurs in conjunction with. For instance, and perhaps the most common recommendation is that deeper breathing which utilizes the diaphragm and abdomen more can encourage relaxation. Practitioners of different disciplines often interpret

1700-400: A term for the volume of air that fills the airways at the end of inhalation, and is breathed out, unchanged, during the next exhalation, never having reached the alveoli. Similarly, the dead space is filled with alveolar air at the end of exhalation, which is the first air to be breathed back into the alveoli during inhalation, before any fresh air which follows after it. The dead space volume of

1785-428: A total of 100 kPa. In dry air, the P O 2 at sea level is 21.0 kPa, compared to a P O 2 of 19.7 kPa in the tracheal air (21% of [100 – 6.3] = 19.7 kPa). At the summit of Mount Everest tracheal air has a total pressure of 33.7 kPa, of which 6.3 kPa is water vapor, reducing the P O 2 in the tracheal air to 5.8 kPa (21% of [33.7 – 6.3] = 5.8 kPa), beyond what

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1870-454: A tutor song and then generate a perfect replica of that song, underlies our ability to learn rhythm. Two very famous computational neuroscientists Kenji Doya and Terrence J. Sejnowski created a model of this using the Zebra Finch as target organism. The Zebra Finch is perhaps one of the most easily understood examples of this among birds. The young Zebra Finch is exposed to a "tutor song" from

1955-467: A typical adult human is about 150 ml. The primary purpose of breathing is to refresh air in the alveoli so that gas exchange can take place in the blood. The equilibration of the partial pressures of the gases in the alveolar blood and the alveolar air occurs by diffusion . After exhaling, adult human lungs still contain 2.5–3 L of air, their functional residual capacity or FRC. On inhalation, only about 350 mL of new, warm, moistened atmospheric air

2040-500: Is 50 kPa, a doubling of the volume of the lungs results in a pressure gradient of the only 25 kPa. In practice, because we breathe in a gentle, cyclical manner that generates pressure gradients of only 2–3 kPa, this has little effect on the actual rate of inflow into the lungs and is easily compensated for by breathing slightly deeper. The lower viscosity of air at altitude allows air to flow more easily and this also helps compensate for any loss of pressure gradient. All of

2125-517: Is a complicated action that involves a coordinated rhythm from the medulla . The first CPG was discovered by removing neurons from a locust. It was observed that the group of neurons was still firing as if the locust was in flight. In 1994, evidence of CPG's in humans was found. A former quadrapalegic began to have some very limited movement in his lower legs. Upon lying down, he noticed that if he moved his hips just right his legs began making walking motions. The rhythmic motor patterns were enough to give

2210-421: Is accounted for by a reduction of atmospheric pressure alone (7.1 kPa). The pressure gradient forcing air into the lungs during inhalation is also reduced by altitude. Doubling the volume of the lungs halves the pressure in the lungs at any altitude. Having the sea level air pressure (100 kPa) results in a pressure gradient of 50 kPa but doing the same at 5500 m, where the atmospheric pressure

2295-722: Is also more effective in very young infants and children than in adults. Inhaled air is by volume 78% nitrogen , 20.95% oxygen and small amounts of other gases including argon , carbon dioxide, neon , helium , and hydrogen . The gas exhaled is 4% to 5% by volume of carbon dioxide, about a hundredfold increase over the inhaled amount. The volume of oxygen is reduced by about a quarter, 4% to 5%, of total air volume. The typical composition is: In addition to air, underwater divers practicing technical diving may breathe oxygen-rich, oxygen-depleted or helium-rich breathing gas mixtures. Oxygen and analgesic gases are sometimes given to patients under medical care. The atmosphere in space suits

2380-455: Is also recommended that it supplies air smoothly without any sudden changes in resistance while inhaling or exhaling. In the graph, right, note the initial spike in pressure on exhaling to open the exhaust valve and that the initial drop in pressure on inhaling is soon overcome as the Venturi effect designed into the regulator to allow an easy draw of air. Many regulators have an adjustment to change

2465-408: Is an increase in the volume of the thoracic cavity . In humans, as in the other mammals , this is achieved primarily through the contraction of the diaphragm , but also by the contraction of the intercostal muscles which pull the rib cage upwards and outwards as shown in the diagrams on the right. During forceful inhalation (Figure on the right) the accessory muscles of inhalation , which connect

2550-412: Is at the ambient pressure of the surrounding water and this has a complex range of physiological and biochemical implications. If not properly managed, breathing compressed gasses underwater may lead to several diving disorders which include pulmonary barotrauma , decompression sickness , nitrogen narcosis , and oxygen toxicity . The effects of breathing gasses under pressure are further complicated by

2635-401: Is breathed in, preventing it from reaching the lungs. The anatomy of a typical mammalian respiratory system, below the structures normally listed among the "upper airways" (the nasal cavities, the pharynx, and larynx), is often described as a respiratory tree or tracheobronchial tree (figure on the left). Larger airways give rise to branches that are slightly narrower, but more numerous than

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2720-494: Is brought in and is well mixed with the FRC. Consequently, the gas composition of the FRC changes very little during the breathing cycle. This means that the pulmonary capillary blood always equilibrates with a relatively constant air composition in the lungs and the diffusion rate with arterial blood gases remains equally constant with each breath. Body tissues are therefore not exposed to large swings in oxygen and carbon dioxide tensions in

2805-450: Is depolarized in the presence of light, unlike the rods which are hyperpolarized. Melanopsin encodes the day-night cycle to the suprachiasmatic nucleus (SCN) via the retinohypothalamic tract . The SCN evokes a response from the spinal cord. Preganglionic neurons in the spinal cord modulate the superior cervical ganglia, which synapses on the pineal gland . The pineal gland synthesizes the neurohormone melatonin from tryptophan . Melatonin

2890-414: Is impossible to suppress the urge to breathe to the point of hypoxia but training can increase the ability to hold one's breath. Conscious breathing practices have been shown to promote relaxation and stress relief but have not been proven to have any other health benefits. Other automatic breathing control reflexes also exist. Submersion, particularly of the face, in cold water, triggers a response called

2975-440: Is increased, because the lungs are more compliant and the equilibrium between the inward recoil of the lungs and outward recoil of the chest wall is disturbed. As such, patients with emphysema often have noticeably broader chests due to the relatively unopposed outward recoil of the chest wall. Total lung capacity also increases, largely as a result of increased functional residual capacity. Obese and pregnant patients will have

3060-414: Is no significant change in FRC as position changes from 0° to Trendelenburg of up to −30°. However, beyond −30°, the drop in FRC is considerable. A lowered or elevated FRC is often an indication of some form of respiratory disease . In restrictive diseases , the decreased total lung capacity leads to a lower FRC. In turn in obstructive diseases , the FRC is increased. For instance, in emphysema , FRC

3145-434: Is pure oxygen. However, this is kept at around 20% of Earthbound atmospheric pressure to regulate the rate of inspiration. Atmospheric pressure decreases with the height above sea level (altitude) and since the alveoli are open to the outside air through the open airways, the pressure in the lungs also decreases at the same rate with altitude. At altitude, a pressure differential is still required to drive air into and out of

3230-443: Is rhythm in its most obvious form. Human beings have an innate ability to listen to a rhythm and track the beat, as seen here "Dueling Banjos". This can be done by bobbing the head, tapping of the feet or even clapping. Jessica Grahn and Matthew Brett call this spontaneous movement "motor prediction". They hypothesized that it is caused by the basal ganglia and the supplementary motor area (SMA). This would mean that those areas of

3315-452: Is secreted into the bloodstream where it affects neural activity by interacting with melatonin receptors on the SCN. The SCN is then able to influence the sleep wake cycle, acting as the "apex of a hierarchy" that governs physiological timing functions. "Rest and sleep are the best example of self-organized operations within neuronal circuits". Sleep and memory have been closely correlated for over

3400-466: Is the volume of air present in the lungs at the end of passive expiration . At FRC, the opposing elastic recoil forces of the lungs and chest wall are in equilibrium and there is no exertion by the diaphragm or other respiratory muscles. FRC is the sum of expiratory reserve volume (ERV) and residual volume (RV) and measures approximately 3000 mL in a 70 kg, average-sized male. It cannot be estimated through spirometry , since it includes

3485-453: Is the theoretical study of the brain used to uncover the principles and mechanisms that guide the development, organization, information-processing and mental abilities of the nervous system. Many computational models have attempted to quantify the process of how various rhythms are created by humans. Juvenile avian song learning is one of the best animal models used to study generation and recognition of rhythm. The ability for birds to process

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3570-485: The diving reflex . This has the initial result of shutting down the airways against the influx of water. The metabolic rate slows down. This is coupled with intense vasoconstriction of the arteries to the limbs and abdominal viscera, reserving the oxygen that is in blood and lungs at the beginning of the dive almost exclusively for the heart and the brain. The diving reflex is an often-used response in animals that routinely need to dive, such as penguins, seals and whales. It

3655-434: The respiratory centers that receive information from the peripheral and central chemoreceptors . These chemoreceptors continuously monitor the partial pressures of carbon dioxide and oxygen in the arterial blood. The first of these sensors are the central chemoreceptors on the surface of the medulla oblongata of the brain stem which are particularly sensitive to pH as well as the partial pressure of carbon dioxide in

3740-402: The "trunk" airway that gives rise to the branches. The human respiratory tree may consist of, on average, 23 such branchings into progressively smaller airways, while the respiratory tree of the mouse has up to 13 such branchings. Proximal divisions (those closest to the top of the tree, such as the trachea and bronchi) function mainly to transmit air to the lower airways. Later divisions such as

3825-544: The Polynesian mana , the Hebrew ruach and the psyche in psychology are related to the concept of breath. In tai chi , aerobic exercise is combined with breathing exercises to strengthen the diaphragm muscles , improve posture and make better use of the body's qi . Different forms of meditation , and yoga advocate various breathing methods. A form of Buddhist meditation called anapanasati meaning mindfulness of breath

3910-465: The RA to be more likely to produce this template of the tutor song, thus leading to learning of the correct song. Dr. Sam Sober explains the process of tutor song recognition and generation using error learning. This refers to a signal generated by the avian brain that corresponds to the error between the tutor song and the auditory feedback the bird gets. The signal is simply optimized in order to be as small of

3995-407: The abdominal muscles, instead of being passive, now contract strongly causing the rib cage to be pulled downwards (front and sides). This not only decreases the size of the rib cage but also pushes the abdominal organs upwards against the diaphragm which consequently bulges deeply into the thorax. The end-exhalatory lung volume is now less air than the resting "functional residual capacity". However, in

4080-432: The above effects of low atmospheric pressure on breathing are normally accommodated by increasing the respiratory minute volume (the volume of air breathed in — or out — per minute), and the mechanism for doing this is automatic. The exact increase required is determined by the respiratory gases homeostatic mechanism , which regulates the arterial P O 2 and P CO 2 . This homeostatic mechanism prioritizes

4165-435: The accessory muscles of inhalation are activated, especially during labored breathing , the clavicles are pulled upwards, as explained above. This external manifestation of the use of the accessory muscles of inhalation is sometimes referred to as clavicular breathing , seen especially during asthma attacks and in people with chronic obstructive pulmonary disease . Ideally, air is breathed first out and secondly in through

4250-421: The active muscles. This carbon dioxide diffuses into the venous blood and ultimately raises the partial pressure of carbon dioxide in the arterial blood. This is immediately sensed by the carbon dioxide chemoreceptors on the brain stem. The respiratory centers respond to this information by causing the rate and depth of breathing to increase to such an extent that the partial pressures of carbon dioxide and oxygen in

4335-411: The adoption of a deeper breathing pattern is to strengthen the body's core. During the process of deep breathing, the thoracic diaphragm adopts a lower position in the core and this helps to generate intra-abdominal pressure which strengthens the lumbar spine. Typically, this allows for more powerful physical movements to be performed. As such, it is frequently recommended when lifting heavy weights to take

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4420-463: The adult, during a critical period. This is defined as the time of life that learning can take place, in other words when the brain has the most plasticity . After this period, the bird is able to produce an adult song, which is said to be crystallized at this point. Doya and Sejnowski evaluated three possible ways that this leaning could happen, an immediate, one shot perfection of the tutor song, error learning, and reinforcement learning. They settled on

4505-452: The air flow through the nasal passages. The word "spirit" comes from the Latin spiritus , meaning breath. Historically, breath has often been considered in terms of the concept of life force. The Hebrew Bible refers to God breathing the breath of life into clay to make Adam a living soul ( nephesh ). It also refers to the breath as returning to God when a mortal dies. The terms spirit, prana ,

4590-411: The arterial blood return almost immediately to the same levels as at rest. The respiratory centers communicate with the muscles of breathing via motor nerves, of which the phrenic nerves , which innervate the diaphragm, are probably the most important. Automatic breathing can be overridden to a limited extent by simple choice, or to facilitate swimming , speech , singing or other vocal training. It

4675-600: The arterial partial pressure of carbon dioxide and lowers the pH of the ECF. Both cause distressing symptoms. Breathing has other important functions. It provides a mechanism for speech , laughter and similar expressions of the emotions. It is also used for reflexes such as yawning , coughing and sneezing . Animals that cannot thermoregulate by perspiration , because they lack sufficient sweat glands , may lose heat by evaporation through panting. The lungs are not capable of inflating themselves, and will expand only when there

4760-413: The atmospheric pressure (and therefore the atmospheric P O 2 ) falls to below 75% of its value at sea level, oxygen homeostasis is given priority over carbon dioxide homeostasis. This switch-over occurs at an elevation of about 2,500 metres (8,200 ft). If this switch occurs relatively abruptly, the hyperventilation at high altitude will cause a severe fall in the arterial P CO 2 with

4845-404: The blood and cerebrospinal fluid . The second group of sensors measure the partial pressure of oxygen in the arterial blood. Together the latter are known as the peripheral chemoreceptors, and are situated in the aortic and carotid bodies . Information from all of these chemoreceptors is conveyed to the respiratory centers in the pons and medulla oblongata , which responds to fluctuations in

4930-401: The blood caused by the breathing cycle, and the peripheral and central chemoreceptors measure only gradual changes in dissolved gases. Thus the homeostatic control of the breathing rate depends only on the partial pressures of oxygen and carbon dioxide in the arterial blood, which then also maintains a constant pH of the blood. The rate and depth of breathing is automatically controlled by

5015-458: The brain would be responsible for spontaneous rhythm generation, although further research is required to prove this. However, they did prove that the basal ganglia and SMA are highly involved in rhythm perception. In a study where patients brain activity was recorded using fMRI , increased activity was seen in these areas both in patients moving spontaneously (bobbing their head) and in those who were told to stay still. Computational neuroscience

5100-568: The ease of inhaling so that breathing is effortless. Abnormal breathing patterns include Kussmaul breathing , Biot's respiration and Cheyne–Stokes respiration . Other breathing disorders include shortness of breath (dyspnea), stridor , apnea , sleep apnea (most commonly obstructive sleep apnea ), mouth breathing , and snoring . Many conditions are associated with obstructed airways. Chronic mouth breathing may be associated with illness. Hypopnea refers to overly shallow breathing ; hyperpnea refers to fast and deep breathing brought on by

5185-401: The game one must recognize rhythmic patterns of other players and perform actions calibrated to these movements. "The rhythm of a game of basketball emerges from the rhythm of individuals, the rhythm among team members, and the rhythmic contrasts between opposing teams". Although the exact oscillatory pattern that modulates different sports has not been found, there have been studies done to show

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5270-431: The importance of breathing regulation and its perceived influence on mood in different ways. Buddhists may consider that it helps precipitate a sense of inner-peace, holistic healers that it encourages an overall state of health and business advisers that it provides relief from work-based stress. During physical exercise, a deeper breathing pattern is adapted to facilitate greater oxygen absorption. An additional reason for

5355-429: The lungs as it is at sea level. The mechanism for breathing at altitude is essentially identical to breathing at sea level but with the following differences: The atmospheric pressure decreases exponentially with altitude, roughly halving with every 5,500 metres (18,000 ft) rise in altitude. The composition of atmospheric air is, however, almost constant below 80 km, as a result of the continuous mixing effect of

5440-401: The man painful muscle fatigue. A key part of CPG's is half-center oscillators. In its simplest form, this refers to two neurons capable of rhythmogenesis when firing together. The generation of a biological rhythm, or rhythmogenesis, is done by a series of inhibition and activation. For example, a first neuron inhibits a second one while it fires, however, it also induces slow depolarization in

5525-403: The nose . The nasal cavities (between the nostrils and the pharynx ) are quite narrow, firstly by being divided in two by the nasal septum , and secondly by lateral walls that have several longitudinal folds, or shelves, called nasal conchae , thus exposing a large area of nasal mucous membrane to the air as it is inhaled (and exhaled). This causes the inhaled air to take up moisture from

5610-561: The nose and pharynx before it enters the alveoli. The saturated vapor pressure of water is dependent only on temperature; at a body core temperature of 37 °C it is 6.3 kPa (47.0 mmHg), regardless of any other influences, including altitude. Consequently, at sea level, the tracheal air (immediately before the inhaled air enters the alveoli) consists of: water vapor ( P H 2 O = 6.3 kPa), nitrogen ( P N 2 = 74.0 kPa), oxygen ( P O 2 = 19.7 kPa) and trace amounts of carbon dioxide and other gases,

5695-407: The nose to the alveoli. The number of respiratory cycles per minute is the breathing or respiratory rate , and is one of the four primary vital signs of life. Under normal conditions the breathing depth and rate is automatically, and unconsciously, controlled by several homeostatic mechanisms which keep the partial pressures of carbon dioxide and oxygen in the arterial blood constant. Keeping

5780-415: The partial pressure of carbon dioxide in the arterial blood unchanged under a wide variety of physiological circumstances, contributes significantly to tight control of the pH of the extracellular fluids (ECF). Over-breathing ( hyperventilation ) increases the arterial partial pressure of carbon dioxide, causing a rise in the pH of the ECF. Under-breathing ( hypoventilation ), on the other hand, decreases

5865-401: The partial pressures of carbon dioxide and oxygen in the arterial blood by adjusting the rate and depth of breathing, in such a way as to restore the partial pressure of carbon dioxide to 5.3 kPa (40 mm Hg), the pH to 7.4 and, to a lesser extent, the partial pressure of oxygen to 13 kPa (100 mm Hg). For example, exercise increases the production of carbon dioxide by

5950-441: The perturbation. This provides strong support for error learning in humans. This animal model has been said to be more similar to humans than birds. It has been shown that humans demonstrate 15–30 Hz (Beta) oscillations in the cortex while performing muscle coordination exercises. This was also seen in macaque monkey cortices. The cortical local field potentials (LFPs) of conscious monkeys were recorded while they performed

6035-414: The regulation of the arterial P CO 2 over that of oxygen at sea level. That is to say, at sea level the arterial P CO 2 is maintained at very close to 5.3 kPa (or 40 mmHg) under a wide range of circumstances, at the expense of the arterial P O 2 , which is allowed to vary within a very wide range of values, before eliciting a corrective ventilatory response. However, when

6120-439: The residual volume. In order to measure RV precisely, one would need to perform a test such as nitrogen washout , helium dilution or body plethysmography . Positioning plays a significant role in altering FRC. It is highest when in an upright position and decreases as one moves from upright to supine/prone or Trendelenburg position. The greatest decrease in FRC occurs when going from 60° to totally supine at 0°. There

6205-449: The respiratory bronchioles, alveolar ducts and alveoli are specialized for gas exchange . The trachea and the first portions of the main bronchi are outside the lungs. The rest of the "tree" branches within the lungs, and ultimately extends to every part of the lungs . The alveoli are the blind-ended terminals of the "tree", meaning that any air that enters them has to exit the same way it came. A system such as this creates dead space ,

6290-610: The respiratory muscles. These muscles are controlled by a rhythm generating network in the brain stem. These neurons comprise the ventral respiratory group (VRG). Although this process is not fully understood, it is believed to be governed by a CPG and there have been several models proposed. The classic three phase model of respiration was proposed by D.W. Richter. It contains 2 stages of breathing, inspiratory and expiratory, that are controlled by three neural phases, inspiration, post-inspiration and expiration. Specific neural networks are dedicated to each phase. They are capable of maintaining

6375-417: The ribs and sternum to the cervical vertebrae and base of the skull, in many cases through an intermediary attachment to the clavicles , exaggerate the pump handle and bucket handle movements (see illustrations on the left), bringing about a greater change in the volume of the chest cavity. During exhalation (breathing out), at rest, all the muscles of inhalation relax, returning the chest and abdomen to

6460-541: The rule. This is just one example of how rhythm could contribute to humans unique cognitive abilities. A central pattern generator (CPG) is defined as a neural network that does not require sensory input to generate a rhythm. This rhythm can be used to regulate essential physiological processes. These networks are often found in the spinal cord. It has been hypothesized that certain CPG's are hardwired from birth. For example, an infant does not have to learn how to breathe and yet it

6545-405: The same time, with the temporal resolution that the circuitry of the brain requires. These techniques include EEG , MEG , fMRI , optical recordings , and single-cell recordings . Techniques such as large scale single-cell recordings are movements in the direction of analyzing overall brain rhythms. However, these require invasive procedures, such as tetrode implantation , which does not allow

6630-470: The second neuron. This is followed by the release of an action potential from the second neuron as a result of depolarization, which acts on the first in a similar fashion. This allows for self-sustaining patterns of oscillation. Furthermore, new motor patterns, such as athletic skills or the ability to play an instrument, also use half-center oscillators and are simply learned perturbations to CPG's already in place. Ventilation requires periodic movements of

6715-471: The third scheme. Reinforcement learning consists of a "critic" in the brain capable of evaluating the difference between the tutor and the template song. Assuming the two are closer than the last trial, this "critic" then sends a signal activating NMDA receptors on the articulator of the song. In the case of the Zebra Finch, this articulator is the robust nucleus of archistriatum or RA. The NMDA receptors allow

6800-423: The total atmospheric pressure is 33.7 kPa, oxygen still constitutes 21% of the atmosphere but its partial pressure is only 7.1 kPa (i.e. 21% of 33.7 kPa = 7.1 kPa). Therefore, a greater volume of air must be inhaled at altitude than at sea level in order to breathe in the same amount of oxygen in a given period. During inhalation, air is warmed and saturated with water vapor as it passes through

6885-463: The types of rhythm that humans are able to generate, be it from recognition of others or sheer creativity. Muscle coordination, muscle memory , and innate game awareness all rely on the nervous system to produce a specific firing pattern in response to an either an efferent or afferent signal. Sports are governed by the same production and perception of oscillations that govern much of human activity. For example, in basketball, in order to anticipate

6970-414: The use of one or more special gas mixtures . Air is provided by a diving regulator , which reduces the high pressure in a diving cylinder to the ambient pressure. The breathing performance of regulators is a factor when choosing a suitable regulator for the type of diving to be undertaken. It is desirable that breathing from a regulator requires low effort even when supplying large amounts of air. It

7055-425: The weather. The concentration of oxygen in the air (mmols O 2 per liter of air) therefore decreases at the same rate as the atmospheric pressure. At sea level, where the ambient pressure is about 100  kPa , oxygen constitutes 21% of the atmosphere and the partial pressure of oxygen ( P O 2 ) is 21 kPa (i.e. 21% of 100 kPa). At the summit of Mount Everest , 8,848 metres (29,029 ft), where

7140-416: The wet mucus , and warmth from the underlying blood vessels, so that the air is very nearly saturated with water vapor and is at almost body temperature by the time it reaches the larynx . Part of this moisture and heat is recaptured as the exhaled air moves out over the partially dried-out, cooled mucus in the nasal passages, during exhalation. The sticky mucus also traps much of the particulate matter that

7225-572: Was first introduced by Buddha . Breathing disciplines are incorporated into meditation, certain forms of yoga such as pranayama , and the Buteyko method as a treatment for asthma and other conditions. In music, some wind instrument players use a technique called circular breathing . Singers also rely on breath control . Common cultural expressions related to breathing include: "to catch my breath", "took my breath away", "inspiration", "to expire", "get my breath back". Certain breathing patterns have

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