Effect of Inhaling Various Concentrations of CO2 on Electrical Activity of the Heart

Exhalation, (breathing out), is the opposite of inhalation and occurs when the inspiratory muscles relax causing the diaphragm to depress which decreases the lung volume. This decrease in volume causes the alveolar pressure to increase therefore the carbon dioxide in the lungs flows from a high pressure to a lower pressure in the atmosphere. (Tortora & Derrickson, 2011)

Answer 2: The respiratory system functions in the exchange of gases with the outside environment. Oxygen is inhaled through the nasal cavity or the mouth, and it travels to the alveoli in the lungs. There, the capillaries exchange the oxygen for carbon dioxide. The oxygenated blood flows back to the heart from the lungs. It enters the left side of the heart and is delivered to all the body tissues via the aorta. In the capillaries of the body tissues, oxygen is exchanged for carbon dioxide. This deoxygenated blood flows back to the right side of the heart and then to the lung. In the capillaries that run across the alveoli, carbon dioxide is exchanged for oxygen that has recently been inhaled. The carbon dioxide will then be exhaled through the mouth and nasal cavity.

The respiratory system is a complex organ structure of the human body anatomy, and the primary purpose of this system is to supply the blood with oxygen in order for the blood vessels to carry the precious gaseous element to all parts of the body to accomplish cell respiration. The respiratory system completes this important function of breathing throughout inspiration. In the breathing process inhaling oxygen is essential for cells to metabolize nutrients and carry out some other tasks, but it must occur simultaneously with exhaling when the carbon dioxide is excreted, this exchange of gases is the respiratory system's means of getting oxygen to the blood (McGowan, Jefferies & Turley, 2004).

THE CONTROL SYSTEM FOR RESPIRATION The control unit of ventilation consists of a processor or breathing centre in the brain which integrates emotional, chemical and physical stimuli inputs and controls an effector - in this case the lungs via motor nerves from the spinal cord. Ventilation is normally autonomic with a limited voluntary override. Ondine's curse is the exception to this where the autonomic control is lost. The mechanism of generation is not completely understood but involves the integration of neural signals by respiratory control centres in the medulla and pons. In the medulla we have the ventral respiratory group i.e. nucleus retroambigualis, nucleus ambiguus, nucleus parambigualis and the pre-Botzinger complex. This group controls voluntary forced exhalation and also works to increase the force of inspiration. The medulla also contains the dorsal respiratory group consisting mainly of the nucleus tractus solitarius and this controls mostly inspiratory movements and their timing. The pons contains the pneumotaxic centre which is involved with the fine tuning of the respiration rate and the apneustic centre. In addition there is further integration in the anterior horn cells of the spinal cord. The actual breathing rate of a human is controlled in the following way. Chemoreceptors detect the levels of carbon dioxide in the blood by monitoring

Small air sacks called alveoli are at the tips of the bronchioles. When air reaches them, the oxygen concentration is high, which causes diffusion into red blood cells travelling through pulmonary capillaries (7). The red blood cells then distribute the new oxygen to the rest of the body. When they reach the alveoli again, they exchange carbon dioxide (a form of cell waste) for new oxygen, and repeat the process. The carbon dioxide is moved through the bronchioles, bronchi, and trachea in the form of exhalation.

If the CO2 falls below the standard range, the respiratory centre reverses this process like in acute panic attacks for instance. If the person breathes too much due to anxiety or like in fear, the respiratory centre reacts by transmitting a signal to decrease breathing. This, in turn, results in the person becoming even more panicked, “I cannot breathe’’; hence the recommendation to inhale from a paper bag.

The air pressures and volumes are essential to breathing. During inhalation the diaphragm contracts allowing the

The main organs of the respiratory system are the lungs – they are the location where the gas exchange between oxygen and carbon dioxide takes place. The lungs therefore expand when you breathe in, and retract when you breathe out. This is done through the diaphragm – a sheet of muscle that is positioned under the lungs. As one inhales, their diaphragm contracts and moves itself downward, increasing the space for your lungs to expand to. The ribs also move to enlarge the possible area the lungs can expand to. This pressure causes air to be sucked through the body to the lungs. When one exhales, the opposite takes place – the diaphragm moves upwards and returns to normal, allowing the process to happen again.

In their Respiratory system, the trachea allows the carbon dioxide filled air into the lungs,

messages to the intercostal muscles and the diaphram. So the rate of breathing is regulated by the

Hyperventilation (over-breathing) lowers the tension of CO2 in alveolar air, less fresh air enter the alveoli and respiratory rate increase without increase metabolism (Eugene & Stead, 1960); (Silverthorn, 2010). In addition, the rate of breathing are control by the respiratory centre in the medulla. The activity of the respiratory centre can be influenced by oxygen, carbon dioxide and hydrogen ions which are monitor by peripheral and central chemoreceptors in the medulla. Chemoreceptor also determine the duration of breath hold, the length of breath hold reduce when oxygen concentration in blood decrease and carbon dioxide concentration in blood increase. When carbon dioxide concentration is high, reach the breaking point, around 50mmHg (McArdle,

Which type of breathing resulted in PCO2 levels closest to the ones we experimented with in this activity – normal

Hyperventilation elevates the subject’s ability to hold their breath by reducing the PCO2 level in the blood. Hence, breathing will start a bit late when PCO2 reaches its threshold level which will activate the chemoreceptors in the respiratory center. Consequently, the chemoreceptors will send a signal to the control center in the brain stem which will respond to the somatic motor neurons and trigger the respiratory muscles to start the breathing again.

Rebreathing air reabsorbs CO2 that was exhaled, and recycling unused O2, this causes CO2 levels to be higher than normal and for blood to have a lower pH. The oxygen content decrease slowly because there is a reservoir of oxygen attached to hemoglobin (Fox 556). An increase of H+ cannot influence the medullary receptors, but carbon dioxide in the arterial blood can cross the blood-brain barrier and lower the pH of cerebrospinal fluid and brain interstitial fluid (Fox 557). Lower in pH on the medulla oblongata stimulates the central chemoreceptors, either directly or via glia cells to release ATP as a transmitter in response to lowered pH (Fox 557). This will then increase ventilation but in several minutes. Aortic and carotid bodies sense the

Every day, thousands of calls are generated to emergency medical systems to summons help for numerous reasons. One of the most frightening calls a dispatcher can receives are those involving a patient who is not breathing or is struggling to breathe. One very common problem that goes unseen due to its colorless, odorless and tasteless properties, and is a major worldwide public health problem, is poisoning from carbon monoxide (Graber et al 2007). According to the Journal of the American Medical Association, 2000 Americans die each year from accidental exposure to carbon monoxide and another 2,300 from intentional exposure (suicide).