Chapter 6: Diving Physiology

New divers may hyperventilate due to anxiety. Hyperventilation is a common response to stress and anxiety, and it can occur in various situations, including diving. When a person hyperventilates, they breathe rapidly and shallowly, which can lead to a decrease in carbon dioxide levels in the body. This can cause symptoms such as lightheadedness, dizziness, and tingling sensations. Therefore, it is possible for new divers to hyperventilate due to anxiety before or during a dive.

It is important to practice and build skill and confidence before using a dry suit in leadership diving situations because dry suits require additional training and experience to properly use and handle. Leadership diving situations often involve more complex and challenging conditions, and using a dry suit adds another layer of complexity. Therefore, it is crucial to have a good understanding of how to use a dry suit effectively and confidently before using it in leadership diving situations.

It is important for all diabetics to be evaluated by a physician before diving because diving can pose certain risks and challenges for individuals with diabetes. The evaluation will help determine if the person's diabetes is well-managed and if they are physically fit to engage in diving activities. The physician can provide guidance on necessary precautions, such as monitoring blood sugar levels, ensuring proper medication management, and addressing any potential complications that may arise during diving. This evaluation is crucial to ensure the safety and well-being of the diabetic individual while diving.

Capillaries are smaller blood vessels that connect the arteries and veins. They have thin walls and a large surface area, allowing for the exchange of oxygen, nutrients, and waste products between the blood and surrounding tissues. Capillaries play a crucial role in delivering oxygen and nutrients to cells and removing waste products from them. They are responsible for the exchange of substances between the blood and tissues, ensuring proper functioning of organs and tissues throughout the body.

Lipid pneumonia is a condition caused by the inhalation or aspiration of fatty substances into the lungs, leading to inflammation and potential lung damage. It is a serious condition that requires immediate medical attention. If left untreated, lipid pneumonia can lead to respiratory failure and other complications. Therefore, it is crucial for victims of lipid pneumonia to seek immediate medical care at a medical facility.

If carbon monoxide poisoning is suspected, administering 100% oxygen is the correct course of action. Carbon monoxide is a toxic gas that can displace oxygen in the bloodstream, leading to oxygen deprivation in the body. By providing 100% oxygen, it helps to increase the oxygen levels in the blood and assists in removing carbon monoxide from the body. This treatment is essential in preventing further harm and promoting recovery in individuals affected by carbon monoxide poisoning.

Type II DCS involves the nervous system and is more serious than Type I DCS. Decompression sickness (DCS) occurs when dissolved gases in the body, such as nitrogen, come out of solution and form bubbles, causing various symptoms. Type II DCS specifically affects the nervous system and can lead to neurological symptoms like numbness, tingling, paralysis, or even loss of consciousness. This type of DCS requires immediate medical attention and is considered more severe compared to Type I DCS, which primarily affects the musculoskeletal system.

For both types of DCS (Decompression Sickness), administering 100% oxygen is recommended. Oxygen helps to reduce the size of nitrogen bubbles formed in the body during decompression, allowing them to be eliminated more easily. It also helps to improve blood oxygen levels and promote healing. Therefore, providing 100% oxygen is a crucial part of the treatment for DCS.

Hypoxia refers to a condition where there is a lack of oxygen in the body's tissues. This can occur due to various reasons such as decreased oxygen levels in the air, respiratory diseases, or impaired oxygen-carrying capacity of the blood. In hypoxia, the body's cells are deprived of the oxygen they need to function properly, leading to symptoms like shortness of breath, confusion, and fatigue. Hypercapnia, on the other hand, refers to high levels of carbon dioxide in the blood, while lipoid pneumonia is a condition caused by the inhalation or aspiration of fatty substances. Hyperventilation is a rapid and deep breathing pattern that can lead to changes in blood pH and oxygen levels, but it is not synonymous with hypoxia.

Arteries carry oxygen-rich blood from the heart to the rest of the body. Unlike veins, which carry oxygen-depleted blood back to the heart, arteries have thick, elastic walls that allow them to withstand the high pressure generated by the heart's contractions. This enables arteries to efficiently transport oxygenated blood to all tissues and organs, ensuring proper oxygen supply for cellular functions. Capillaries, on the other hand, are tiny blood vessels that facilitate the exchange of oxygen, nutrients, and waste products between the blood and surrounding tissues. Blood, while essential for the functioning of the circulatory system, does not specifically carry oxygen-rich blood from the heart like arteries do.

Hyperventilation is the result of breathing more than necessary. This can lead to an imbalance in the levels of oxygen and carbon dioxide in the body. When we hyperventilate, we take in excessive amounts of oxygen and exhale more carbon dioxide than usual. This can cause symptoms such as dizziness, lightheadedness, tingling in the extremities, and a feeling of shortness of breath. Hyperventilation is often triggered by anxiety or panic attacks, but can also occur due to certain medical conditions or medications.

Arterial Gas Embolism occurs when air bubbles enter the bloodstream and block the flow of blood to vital organs. This can be caused by ascending too quickly while scuba diving or during medical procedures. The symptoms of arterial gas embolism include feeling terrible, difficulty breathing, and noticeable changes in behavior or appearance. Therefore, the statement is true.

Carbon monoxide poisoning occurs when carbon monoxide, a toxic gas, is inhaled and binds to hemoglobin in red blood cells, forming carboxyhemoglobin. This reduces the ability of hemoglobin to carry oxygen to tissues, leading to tissue hypoxia. Therefore, the statement that carbon monoxide poisoning leads to tissue hypoxia is true.

When a person is showing signs of hypoxia, giving them 100% oxygen is the correct course of action. Hypoxia is a condition where there is a lack of oxygen supply to the body's tissues. By providing 100% oxygen, it ensures that the person receives an adequate amount of oxygen to meet their body's needs. This can help alleviate the symptoms of hypoxia and prevent further complications.

Nitrogen is an inert gas that is not used by the body. While oxygen is essential for cellular respiration and carbon dioxide is a waste product of metabolism, nitrogen is not directly utilized by the body. It is the most abundant gas in the atmosphere and plays a role in various chemical reactions, but it is not actively involved in bodily functions or metabolism.

The statement suggests that to make the diagnosis process simpler, Acute Gastroenteritis (AGE) and Diarrheal Complications Syndrome (DCS) should be treated as the same condition, at least in the beginning. This means that when a patient presents symptoms of either AGE or DCS, they should be initially treated as if they have the same underlying cause. This approach can help streamline the diagnostic process and ensure that appropriate treatment is provided promptly.

Dead Air Space refers to the volume of air that exists in the mouth and windpipe, but is not usable by the respiratory system. This air does not participate in gas exchange and remains stagnant. It is called "dead" because it does not contribute to the oxygenation of blood. Dead Air Space is important to consider when measuring lung function and can vary depending on factors such as body size and lung health.

The two cavities on the bottom of the heart are called ventricles. The ventricles are the lower chambers of the heart that pump blood to the rest of the body. They receive blood from the atria and contract to push the blood out of the heart. The left ventricle pumps oxygenated blood to the body, while the right ventricle pumps deoxygenated blood to the lungs. The ventricles play a crucial role in maintaining blood circulation and ensuring that oxygenated blood reaches all parts of the body.

Total Lung Capacity refers to the maximum volume of air that the lungs can hold. It is the sum of all lung volumes, including tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume. Tidal volume is the volume of air inhaled and exhaled during normal breathing. Vital capacity is the maximum amount of air that can be forcefully exhaled after a maximum inhalation. Dead Air Space refers to the volume of air in the respiratory system that does not participate in gas exchange. Residual volume is the volume of air that remains in the lungs after a maximum exhalation.

Veins carry oxygen-depleted blood back to the heart. Unlike arteries, which carry oxygenated blood away from the heart, veins transport deoxygenated blood from the body's tissues back to the heart for reoxygenation. This is essential for the oxygenation of cells and the removal of waste products from the body. Veins have thinner walls and valves that prevent the backward flow of blood, ensuring efficient circulation.

Breath holding while ascending can cause pulmonary barotrauma. This is because as a person ascends, the pressure decreases, causing the air inside the lungs to expand. If the person holds their breath, this expansion can lead to the rupture of lung tissue, resulting in pulmonary barotrauma. This condition can cause symptoms such as chest pain, coughing up blood, and difficulty breathing. It is important to exhale continuously while ascending to prevent this condition.

Tension pneumothorax occurs when air escapes from the lung through a hole during exhalation but is unable to re-enter during inhalation. This creates a buildup of air in the pleural space, leading to increased pressure and compression of the lung and other nearby structures. This condition can be life-threatening and requires immediate medical attention.

Carbon Monoxide Poisoning usually happens when compressed air has been tainted because the compressor drew in its own exhaust. Carbon monoxide is a toxic gas that is produced when fuels like gasoline, propane, or wood are burned. When the compressor draws in its own exhaust, it can introduce carbon monoxide into the compressed air system. Breathing in this tainted air can lead to carbon monoxide poisoning, which can cause symptoms like headache, dizziness, nausea, confusion, and even death in severe cases.

Residual Volume refers to the volume of air that remains in the lungs after a maximal exhalation. It represents the amount of air that cannot be expelled from the lungs and is necessary to maintain lung function and prevent lung collapse. This volume is important for gas exchange and helps to ensure that there is a continuous supply of oxygen to the body tissues.

Boyle's Law states that the pressure of a gas is inversely proportional to its volume, assuming constant temperature. Therefore, on descent, as the volume of air spaces in the body and in equipment decreases, the pressure of the air in those spaces increases. This leads to compression of the air spaces, as described in the question.

Pneumothorax is a condition where air accumulates in the space between the lung and the chest wall, causing the lung to collapse partially or completely. This can occur due to various reasons such as trauma, underlying lung diseases, or spontaneous rupture of a lung bleb. When air enters the pleural space, it disrupts the normal negative pressure, leading to lung collapse. Symptoms of pneumothorax include sudden sharp chest pain, shortness of breath, and decreased breath sounds on the affected side. Prompt medical attention is required to relieve the pressure and reinflate the lung.

Subcutaneous emphysema occurs when air from the lungs escapes and accumulates under the skin in the neck area. This can happen due to various reasons such as trauma, lung infections, or medical procedures. The air creates a characteristic swelling and crackling sensation when touched. Arterial gas embolism refers to the presence of air bubbles in the bloodstream, pneumothorax is the accumulation of air in the pleural cavity, mediastinal emphysema is the presence of air in the mediastinum, and hyperventilation is rapid and deep breathing. None of these conditions specifically involve air collecting under the skin in the neck area.

At sea level, the average body holds about one liter of absorbed nitrogen. This means that the average person's body contains approximately one liter of nitrogen when at sea level.

In diving medicine, decompression dives refer to dives that require the diver to make stops at various depths during ascent to allow the body to release excess nitrogen absorbed during the dive. This is done to prevent decompression sickness. Since all dives require some form of decompression, the statement is true.

Arterial Gas Embolism is caused by escaped air from the lungs entering the bloodstream through the capillaries surrounding the alveoli. This condition occurs when air bubbles or gas enter the arterial circulation and can block blood flow to vital organs. It can be caused by various factors such as diving accidents, medical procedures, or trauma. Symptoms may include chest pain, difficulty breathing, confusion, and loss of consciousness. Prompt medical attention is required to treat this condition and prevent further complications.

Subcutaneous emphysema causes "rice krispies" under the skin. Subcutaneous emphysema occurs when air gets trapped in the layer of tissue beneath the skin. This can happen due to various reasons such as trauma, infection, or certain medical procedures. When air accumulates in the subcutaneous tissue, it creates a characteristic crackling sensation and sound when touched, resembling the sound of rice krispies. This condition is typically not dangerous on its own, but it may indicate an underlying issue that needs to be addressed.

We breathe to rid ourselves of excess carbon dioxide. When we inhale, oxygen enters our lungs and is transferred to our bloodstream, where it is carried to our body's cells. As our cells use oxygen to produce energy, carbon dioxide is produced as a waste product. This carbon dioxide is then carried back to our lungs through the bloodstream and exhaled when we breathe out. By breathing, we ensure that our body maintains a balance of oxygen and carbon dioxide, preventing the buildup of excess carbon dioxide which can be harmful to our health.

Boyle's Law states that the pressure and volume of a gas are inversely proportional at a constant temperature. When ascending, the pressure decreases, causing the air in the lungs to expand. If this expanded air is not released, it can lead to an overexpansion injury, such as a lung rupture or pneumothorax. Therefore, Boyle's Law explains the need to release air from the lungs during ascent to prevent such injuries.

Mediastinal emphysema is the correct answer because it refers to the condition where air escapes from the lungs and accumulates in the mediastinum, the space in the chest between the lungs. This can occur due to trauma or lung disease, causing symptoms such as chest pain, difficulty breathing, and a crackling sensation in the chest.

The two cavities on top of the heart are called atria and auricles. The atria are the upper chambers of the heart, responsible for receiving blood from the veins and pumping it into the ventricles. The auricles, also known as atrial appendages, are small, ear-like extensions of the atria that help increase the capacity of the atria to hold blood. Both the atria and auricles play important roles in the circulation of blood through the heart.

Lipid pneumonia is caused by breathing air tainted with oil. When oil droplets are inhaled, they can accumulate in the lungs and cause inflammation. This inflammation can lead to the development of lipid pneumonia. Symptoms of lipid pneumonia may include coughing, difficulty breathing, chest pain, and fever. Treatment typically involves removing the source of the oil exposure and providing supportive care to alleviate symptoms and promote healing.

The escaped air entering the heart and brain is a sign of Arterial Gas Embolism.

Diffusion is the process of gas exchange that occurs in the lungs every time you breathe. During respiration, oxygen from the inhaled air diffuses across the thin walls of the alveoli in the lungs into the bloodstream. At the same time, carbon dioxide, a waste product, diffuses from the bloodstream into the alveoli to be exhaled. This exchange of gases is made possible by the difference in concentration between the alveoli and the bloodstream, allowing for the movement of molecules from an area of higher concentration to an area of lower concentration.

Hypercapnia is the correct answer because it refers to an excess of carbon dioxide in the body's tissues. This condition occurs when there is a buildup of carbon dioxide in the bloodstream, leading to an imbalance in the body's pH levels. It can be caused by various factors such as hypoventilation, lung diseases, or breathing in environments with high levels of carbon dioxide. Hypercapnia can result in symptoms such as shortness of breath, confusion, and in severe cases, it can be life-threatening.

When a small amount of blood is observed in a diver's mask, it is a sign of sinus squeeze. Sinus squeeze occurs when the diver experiences pressure changes during a dive, causing the sinuses to become blocked or injured. This can result in bleeding from the nose, which can then be seen in the mask. It is important for divers to equalize the pressure in their sinuses regularly during a dive to prevent sinus squeeze and other related issues.

Tidal volume refers to the volume of air that is inhaled and exhaled during a normal breath. It is the amount of air that moves in and out of the lungs with each breath. During rest, the tidal volume is typically lower as less air is needed for the body's oxygen demands. However, during exertion or physical activity, the tidal volume increases to meet the increased oxygen requirements of the body. Therefore, the volume of air moved in and out of the lungs during one breath changes depending on whether a person is at rest or exerting themselves.

This statement is false because having asthma does not necessarily mean that a person cannot dive. While diving can pose risks for individuals with asthma, it is not an absolute contraindication. It is important for individuals with asthma to consult with their healthcare provider and undergo a thorough evaluation to determine if diving is safe for them. With proper management and precautions, many individuals with asthma can safely participate in diving activities.

Pneumothorax usually requires using a tube to remove air, and recompression is not necessary.

Pneumothorax is caused by air escaping from the lung and becoming trapped between the outer lung covering and the inside of the chest cavity. This condition can occur due to various reasons such as lung trauma, lung diseases, or medical procedures. The trapped air puts pressure on the lung, causing it to collapse partially or completely. Symptoms of pneumothorax include sudden sharp chest pain, difficulty breathing, rapid heart rate, and decreased breath sounds on one side of the chest. Treatment usually involves removing the trapped air and allowing the lung to re-expand.

Type I Decompression sickness is the correct answer because the symptoms mentioned, such as pain, itchy skin, burning sensation, and a marbling of the skin, are commonly associated with this condition. Decompression sickness occurs when a person ascends too quickly from a high-pressure environment, such as scuba diving, causing nitrogen bubbles to form in the bloodstream and tissues. These symptoms occur due to the presence of these bubbles, which can block blood vessels and cause tissue damage.

If the eustachian tube is blocked during ascent, it can cause a reverse block. A reverse block occurs when the pressure inside the middle ear becomes higher than the atmospheric pressure, preventing the equalization of pressure. This can lead to discomfort or pain in the ears and potentially affect hearing.

FIRST AID is oxygen, not treatment.

Vital Capacity refers to the maximum amount of air that can be inhaled or exhaled during a single breath. It is the sum of tidal volume, which is the normal amount of air breathed in and out during regular breathing, and inspiratory and expiratory reserve volumes, which are the additional amounts of air that can be inhaled or exhaled forcefully after a normal breath. Therefore, the greatest volume of air that can be moved in and out of the lungs in one maximal breath is the vital capacity.

Hypoxia can be caused by not breathing, such as running out of air or near drowning, as well as when tissues cannot process oxygen for some reason. In both cases, the body is deprived of sufficient oxygen, leading to a decrease in oxygen levels in the blood and tissues. This can result in various symptoms and complications, depending on the severity and duration of the hypoxia. Insufficient safety stops and ascending too fast are not mentioned as causes of hypoxia in the given options.

Nitrogen narcosis is a condition that can occur when divers descend to certain depths underwater. It is caused by the increased pressure at depth, which leads to the absorption of nitrogen into the bloodstream. At 60 feet, the pressure is significant enough to cause nitrogen narcosis in some individuals. This condition can result in symptoms similar to alcohol intoxication, including impaired judgment, confusion, and loss of coordination. Going beyond this depth increases the risk and severity of nitrogen narcosis.