Guyton and Hall Physiology Chapter 45 - Physiology of Deep-Sea Diving and Other Hyperbaric Conditions

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary physiological effect of increasing pressure on the lungs when diving?

Increased blood oxygen levels

Complete lung collapse

Inflation of lungs with compressed air (correct)

Decreased lung volume

At what depth does a diver first start to experience mild symptoms of nitrogen narcosis?

100 feet

120 feet (correct)

150 feet

200 feet

What happens to a diver's strength and motor skills at depths between 200 to 250 feet?

Strength wanes considerably, becoming clumsy (correct)

There is a significant increase in strength

Strength remains unchanged, but awareness increases

The diver exhibits enhanced dexterity

How does nitrogen behave in the body at sea level pressure?

It has no significant effect on bodily function Signup and view all the answers

What condition results from breathing high alveolar gas pressures for an extended period of time?

Nitrogen narcosis Signup and view all the answers

What phenomenon does Boyle's law explain in diving physiology?

Collapse of air chambers due to increased pressure Signup and view all the answers

What happens to the amount of oxygen dissolved in blood when the Po2 exceeds 100 mm Hg?

It increases significantly Signup and view all the answers

At which depth would the alveolar Po2 reach approximately 3000 mm Hg?

300 feet Signup and view all the answers

How does very high Po2 affect the body's enzymatic systems?

It produces oxidizing free radicals that overwhelm the enzyme systems Signup and view all the answers

What is the effect of increased pressure on pulmonary function during diving?

It restricts lung expansion Signup and view all the answers

What is a potential harmful effect of oxygen toxicity in divers?

Damage to lung tissues and enzyme systems Signup and view all the answers

What role does the hemoglobin-O2 buffering mechanism play in oxygen transport?

It becomes ineffective at elevated Po2 levels Signup and view all the answers

What is one consequence of nitrogen solubility in tissues during diving?

Increased risk of decompression sickness Signup and view all the answers

What condition may be caused by prolonged submergence in diving?

Decompression sickness Signup and view all the answers

What is a major cause of oxygen toxicity when exposed to high-pressure oxygen?

Free radicals Signup and view all the answers

How can carbon monoxide impact divers during a mission?

It can lead to carbon monoxide poisoning Signup and view all the answers

Which of the following is a potential effect of pressure on pulmonary function?

Decreased compliance Signup and view all the answers

What biological factor is believed to enhance therapeutic benefits under hyperbaric oxygen conditions?

Oxidizing free radicals Signup and view all the answers

What is a significant risk associated with nitrogen solubility in tissues during deep diving?

Nitrogen narcosis Signup and view all the answers

What is a possible consequence of carbon dioxide buildup in diving gear?

Increased risk of hypercapnia Signup and view all the answers

What is the typical pressure at which oxygen is administered in hyperbaric therapy?

2 to 3 atm Signup and view all the answers

What is a common physiological adaptation to deep diving to prevent oxygen toxicity?

Decreasing metabolic rate Signup and view all the answers

What can contribute to myocardial infarction during diving activities?

Carbon monoxide exposure Signup and view all the answers

What happens to nitrogen levels in the body when a diver remains underwater for an extended period?

Nitrogen becomes saturated in body water and fat. Signup and view all the answers

What is a primary consequence of a rapid ascent to the surface after extended underwater exposure?

Formation of nitrogen bubbles in body fluids. Signup and view all the answers

Which condition is known as decompression sickness?

Bends. Signup and view all the answers

How does high Pco2 affect the respiratory function of a diver?

It causes respiratory acidosis and potential failure. Signup and view all the answers

What can result from the tissue saturation of nitrogen in divers?

Tissue ischemia and possible death. Signup and view all the answers

What is a common effect of nitrogen narcosis experienced by divers?

Severe lethargy. Signup and view all the answers

Which is NOT an effect of extended exposure to high pressures under water?

Prevention of nitrogen absorption. Signup and view all the answers

What describes the condition of the pulmonary capillaries during high pressure underwater?

Saturation with nitrogen. Signup and view all the answers

What commonly occurs when nitrogen bubbles form in body fluids during decompression?

Tissue damage. Signup and view all the answers

In the context of diving, what does hypoxic mean?

Low levels of oxygen. Signup and view all the answers

What is the primary cause of acute oxygen toxicity in deep-sea diving?

Oxidation of polyunsaturated fatty acids Signup and view all the answers

Which cellular component is particularly susceptible to damage from acute oxygen toxicity?

Nervous tissues Signup and view all the answers

What condition develops due to exposure to elevated nitrogen pressures during diving?

Decompression sickness Signup and view all the answers

How does the solubility of nitrogen in body tissues vary?

It is five times more soluble in fat than in water. Signup and view all the answers

What is a significant pulmonary effect of chronic oxygen exposure at 1 atm pressure?

Pulmonary edema Signup and view all the answers

Which of the following is a key symptom associated with decompression sickness?

Joint pain Signup and view all the answers

What role does oxygen play in pulmonary dysfunction during deep-sea diving?

It causes damage to the lining of bronchi and alveoli. Signup and view all the answers

What happens to nitrogen levels in the body tissues when a diver ascends to lower pressure?

Nitrogen is released from tissues into the bloodstream. Signup and view all the answers

What physiological condition can occur due to prolonged exposure to increased levels of oxygen?

Pulmonary fibrosis Signup and view all the answers

Why is carbon dioxide buildup a concern in deep-sea diving gear?

It can lead to hypercapnia and decreased consciousness. Signup and view all the answers

What cellular component is primarily affected by acute oxygen toxicity during deep-sea diving?

Polyunsaturated fatty acids Signup and view all the answers

What is the primary reason for lung issues developing after prolonged exposure to high oxygen pressure at 1 atm?

Damage to the bronchi and alveoli linings due to high oxygen pressure Signup and view all the answers

What condition results from the accumulation of nitrogen in the body tissues during diving activities?

Decompression sickness Signup and view all the answers

Which of the following statements is true regarding nitrogen during deep-sea diving?

Nitrogen dissolves more readily in fat than in water Signup and view all the answers

What is a significant effect of chronic oxygen exposure at 1 atm pressure for extended periods?

Lung passageway congestion Signup and view all the answers

What is the primary reason that toxicity does not increase due to depth alone when a diver is properly equipped?

Alveolar CO2 pressure is maintained at a normal value. Signup and view all the answers

How long does it take for nitrogen in the dissolved state to reach near equilibrium in the body's tissues after diving?

Several hours, depending on the tissue type. Signup and view all the answers

What is the maximum increase in minute respiratory volume a diver can achieve to compensate for increased CO2?

8- to 11-fold increase. Signup and view all the answers

At what alveolar CO2 pressure does tolerance typically decrease, posing challenges for the diver?

80 mm Hg. Signup and view all the answers

What is a significant factor contributing to the slower equilibrium of nitrogen in fat tissue compared to other tissues?

Poor blood supply to fat tissue. Signup and view all the answers

What condition is primarily associated with the formation of nitrogen bubbles following a rapid ascent to the surface after extended diving?

Decompression sickness Signup and view all the answers

What happens to the diver's respiratory system as high levels of carbon dioxide build up during deep diving?

Respiratory depression Signup and view all the answers

What is a potential result of prolonged submersion leading to nitrogen saturation in body tissues?

Severe respiratory acidosis Signup and view all the answers

What is the primary cause of tissue ischemia in divers during decompression sickness?

Formation of nitrogen bubbles Signup and view all the answers

What bodily response occurs when a diver remains under high pressure for an extended time?

Saturation of nitrogen in blood Signup and view all the answers

What can be a direct outcome of the nitrogen saturation in divers?

Dysbarism symptoms Signup and view all the answers

After coming back to the surface, what can happen if a diver ascends too quickly?

Bubble formation in tissues Signup and view all the answers

What physiological process is disrupted by depressant effects of high Pco2 during diving?

Respiratory compensation Signup and view all the answers

What effect does prolonged exposure to high pressure have on fat tissues in divers?

Saturation with nitrogen Signup and view all the answers

What happens at the cellular level due to nitrogen saturation during diving?

Swelling and ischemia Signup and view all the answers

Boyle's law states that increasing pressure can collapse the diver's lungs.

True Signup and view all the answers

Oxygen partial pressures above 100 mm Hg decrease the amount of O2 dissolved in blood.

False Signup and view all the answers

High levels of oxidizing free radicals can overwhelm enzyme systems in the body when Po2 is very elevated.

True Signup and view all the answers

The hemoglobin-O2 buffering mechanism is effective at all Po2 levels.

False Signup and view all the answers

Breathing high-level oxygen pressures can have no significant physiological effects on the diver.

False Signup and view all the answers

At sea level pressure, nitrogen has a significant effect on bodily function.

False Signup and view all the answers

A person 100 feet underwater experiences the same pressure as at an altitude of 100 feet above sea level.

False Signup and view all the answers

The first symptoms of mild nitrogen narcosis can appear at depths of around 120 feet.

True Signup and view all the answers

Breathing compressed air underwater at depths of 150 to 200 feet can result in drowsiness.

True Signup and view all the answers

Increased water pressure underwater has no effect on a diver's strength and motor skills.

False Signup and view all the answers

The primary symptoms of decompression sickness include pain in the joints and muscles, affecting 85% to 90% of individuals.

True Signup and view all the answers

Only 2% of individuals with decompression sickness experience respiratory issues known as 'the chokes'.

True Signup and view all the answers

Nervous system symptoms in decompression sickness occur in 20% to 30% of cases.

False Signup and view all the answers

The term 'bends' is commonly used to refer to the symptoms caused by high oxygen levels in divers.

False Signup and view all the answers

Decompression sickness is characterized by symptoms such as severe pulmonary edema and can occasionally lead to death.

True Signup and view all the answers

Joint pain from decompression sickness accounts for a condition referred to as 'the bends'.

True Signup and view all the answers

Individuals with decompression sickness experience nervous system symptoms in 3% of cases leading to paralysis.

True Signup and view all the answers

A rapid ascent to the surface without proper decompression is beneficial for preventing decompression sickness.

False Signup and view all the answers

The total gaseous pressure in the body during decompression is lower than the pressure at depth.

True Signup and view all the answers

Decompression tables are used to quickly eliminate dissolved nitrogen from a diver's body.

False Signup and view all the answers

Match the following gases with their typical pressures in a decompressed state during a dive:

O2 = 159 mm Hg N2 = 601 H2O = 47 mm Hg CO2 = 40 Signup and view all the answers

Match the following symptoms with their related conditions in decompression sickness:

Joint pain = The bends Shortness of breath = The chokes Dizziness = Nervous system symptoms Paralysis = Severe cases Signup and view all the answers

Match the following values with their relevant total gaseous pressure:

Gaseous pressure in body fluids during a dive = 5000 mm Hg Total pressure at the surface = 760 mm Hg Total pressure after decompression = 4065 Gaseous pressure in body fluids post-decompression = 4065 Signup and view all the answers

Match the following statements with their implications in decompression sickness:

85% to 90% experience pain = Joint pain affects divers mostly 5% to 10% show serious symptoms = Severe nervous system effects 2% may experience the chokes = Massive microbubbles in lungs Temporary paralysis = May become permanent damage Signup and view all the answers

Match the following conditions with their descriptions related to decompression:

Decompression sickness = Caused by rapid ascent The bends = Joint and muscle pain The chokes = Pulmonary edema from bubbles Nitrogen elimination = Occurs during slow ascent Signup and view all the answers

Match the following terms related to diving physiology with their descriptions:

Decompression Sickness = Condition caused by nitrogen bubbles forming in body fluids Narcosis = State of lethargy and impaired sensory perception due to nitrogen Tissue Ischemia = Decreased blood flow to tissues leading to potential damage Anesthesia = Loss of sensation, which can occur from severe exposure Signup and view all the answers

Match the causes of nitrogen solubility in the body to their effects:

High Pressure = Increased nitrogen dissolved in body fluids Long Exposure = Saturation of body water and fat with nitrogen Rapid Ascent = Formation of nitrogen bubbles in body fluids Pulmonary Capillary Saturation = High levels of nitrogen in the bloodstream Signup and view all the answers

Match the diving conditions with their effects on the body:

High Pco2 = Depressed respiratory function Extended Diving = Accumulation of nitrogen in tissues Sudden Ascent = Risk of decompression sickness Chronic Oxygen Exposure = Potential for pulmonary dysfunction Signup and view all the answers

Match the symptoms associated with diving to their descriptions:

Lethargy = Intense fatigue experienced during nitrogen narcosis Severe Respiratory Acidosis = Condition resulting from high CO2 levels Diver's Paralysis = Loss of motor function due to decompression effects Tissue Death = Possible outcome from significant tissue ischemia Signup and view all the answers

Match the effects of nitrogen saturation to their outcomes:

Minor Damage = Low-number nitrogen bubbles affecting tissues Serious Damage = High-number bubbles causing tissue ischemia Anesthesia = Loss of perception due to high nitrogen levels Bubble Formation = Occurs during rapid ascent after deep diving Signup and view all the answers

Study Notes

Pressure vs. Depth

Seawater pressure increases with depth.
Every 33 feet of depth adds the same amount of pressure as the atmosphere at sea level.

High Pressure Physiology

Divers breathe compressed air to maintain lung inflation at depth.
This exposes lungs to very high alveolar gas pressures (hyperbarism).
This increased pressure can lead to physiological changes and even death.

Boyle's Law

Crucial to diving physiology.
Explains how pressure affects gas volume
High pressure compresses gas volume.

Nitrogen Narcosis

Occurs at high nitrogen partial pressures.
Nitrogen is the main component of air.
Causes jovial and carefree feelings at shallow depths (120 feet).
Drowsiness at 150-200 feet.
Weakness and clumsiness at 200-250 feet.

Oxygen Toxicity

High oxygen pressures can be dangerous.
Acute oxygen toxicity affects the nervous system, leading to brain dysfunction.
This happens when the body is exposed to high oxygen pressures for too long.

Chronic Oxygen Poisoning

Affects the lungs, not other tissues.
1 atm pressure of oxygen can be tolerated indefinitely without acute toxicity.
However, lung damage occurs after 12 hours of exposure.
The high pressure directly affects the air spaces in the lungs.

Decompression Sickness

Occurs when divers surface quickly from deep dives.
Dissolved nitrogen in the body forms bubbles, causing damage to tissues.
The amount of nitrogen dissolved depends on the depth and duration of the dive.

Oxygen Transport

High blood oxygen levels increase dissolved oxygen in the blood, independent of hemoglobin capacity.
Hemoglobin-oxygen binding plateaus at high pressures, leading to increased tissue oxygen levels.
This can cause tissue damage and even respiratory depression.

Oxygen Toxicity

High oxygen pressure can be toxic causing oxidative damage to cells, especially in high lipid containing tissues like nervous tissue
Nervous system dysfunction is the main cause of acute oxygen toxicity death
Chronic oxygen exposure can lead to pulmonary dysfunction, namely atelectasis and pulmonary edema, due to lung lining damage

Carbon Dioxide Toxicity

Diving gear should be designed to adequately ventilate and prevent CO2 buildup
CO2 buildup can lead to respiratory acidosis, lethargy, narcosis and anesthesia
CO2 pressure greater than 80 mmHg is intolerable and leads to respiratory failure

Nitrogen Toxicity (Decompression Sickness)

Nitrogen dissolves in body fluids in proportion to the pressure
At sea level, approximately 1 liter of nitrogen dissolves in the body
Nitrogen is more soluble in fat than water
Nitrogen slowly equilibrates in body tissues, with water reaching equilibrium within 1 hour and fat taking several hours
Rapid ascent to the surface can lead to nitrogen bubbles forming in body fluids, causing decompression sickness
Symptoms of decompression sickness include pain, paralysis, neurological dysfunction, and tissue death

Helium and Diving Depth

For deep dives, helium is used in the gas mixture instead of nitrogen to reduce the narcotic effect
Helium is less soluble in body tissues than nitrogen and diffuses out faster
Helium's low density reduces airway resistance, especially important at depth where nitrogen density increases and makes breathing difficult
Oxygen concentration must be reduced at depth to prevent oxygen toxicity

Self-Contained Underwater Breathing Apparatus (SCUBA)

SCUBA systems consist of compressed air tanks, a reducing valve, a demand valve, and a mask system
The demand valve provides air to inhale upon negative pressure and vents exhaled air into the water
SCUBA dive time is limited by the need to ventilate the system of CO2
Deeper dives require a higher air flow to remove CO2

Submarine Escape

Similar problems to deep-sea diving can occur in submarine escape
Rebreathing systems can aid in submarine escape from greater depths
Prevention of air embolism is crucial during escape

Diving Physiology

Pressure increases with depth beneath the sea
Air must be supplied at high pressure to keep lungs inflated
High alveolar gas pressures lead to hyperbarism
Hyperbarism can cause physiological changes and be lethal
33 feet of water pressure = 1 atmosphere of pressure
Boyle's law: increased pressure can compress air chambers in the body, especially the lungs

Nitrogen Narcosis

Nitrogen is the main component of air (about 80%)
At high pressures, nitrogen causes narcosis:
- Mild narcosis: Joviality and loss of care at around 120 feet
- Drowsiness: 150 to 200 feet
- Decreased strength and clumsiness: 200 to 250 feet

Oxygen Toxicity

High partial pressure of oxygen (Po2) above 100 mm Hg increases dissolved oxygen in the blood
At very high Po2, the body's oxygen buffering mechanism fails
Tissues can experience dangerously high Po2 levels
Excess oxygen can cause free radical damage and disrupt enzyme systems

Decompression Sickness

Occurs when dissolved nitrogen bubbles form in tissues during decompression
Symptoms:
- Joint pain (the "bends"): 85-90% of cases
- Nervous system symptoms:
  - Dizziness: 5%
  - Paralysis or collapse: Up to 3%
- "The chokes": Micro bubbles block lung capillaries, causing breathing difficulties, pulmonary edema, and potentially death

Decompression Tables and Nitrogen Elimination

Slow ascent allows dissolved nitrogen to be eliminated safely
Rapid ascent can lead to:
- Lung expansion and rupture of blood vessels
- Air embolism: Gas enters the bloodstream

Submarine Internal Environment

Radiation hazards: Shielding minimizes exposure to cosmic rays
Poisonous gas hazards:
- Cigarette smoke can release carbon monoxide
- Freon leaks can cause toxicity

Hyperbaric Oxygen Therapy

High-pressure oxygen (hyperbaric oxygen) can have therapeutic benefits
Mechanisms of action:
- Increased oxygen delivery to tissues
- Anti-inflammatory effects
- Antibacterial effects
Conditions treated with hyperbaric oxygen:
- Decompression sickness
- Arterial gas embolism
- Carbon monoxide poisoning
- Osteomyelitis
- Myocardial infarction
Oxygen is usually administered at 2-3 atm pressure

Health Problems at Depth

Pressure changes affect the body in many ways
Decompression sickness can be a serious risk to divers
Hyperbaric oxygen therapy can treat various conditions caused by high pressure environments.

Nitrogen Narcosis

Nitrogen dissolves in body fluids and tissues during deep dives.
At deep levels (several hours), both body water and fat become saturated with nitrogen.
As divers ascend, nitrogen can form bubbles in body fluids, causing a range of problems from mild pain to paralysis and death.

Decompression Sickness: The Bends

Decompression sickness occurs when dissolved nitrogen forms bubbles during rapid ascent.
Most common symptoms are pain in the joints and muscles, especially legs and arms.
Nervous system symptoms include dizziness, paralysis, and unconsciousness.
The "chokes" is a life-threatening complication where bubbles block lung capillaries, causing shortness of breath and potentially death.

Preventing Decompression Sickness

Slow ascents allow for controlled nitrogen elimination.
Decompression tables guide divers on safe ascent rates and stopping points.

Helium in Deep Dives

Helium is often used in deep dives instead of nitrogen because:
- It has a lower narcotic effect.
- Less helium dissolves in tissues, and it diffuses out faster.
- Its low density reduces airway resistance during breathing, important in high pressure environments.

SCUBA Diving

SCUBA (self-contained underwater breathing apparatus) allows divers to breathe independently of surface supply.
Demand valve in the mask delivers air only on inhalation, with pressure slightly higher than surrounding water.
Exhalation is into the water, preventing air from returning to the tank.
During ascent, special exhalation efforts are needed to prevent air embolism.

Submarine Medicine

Submarine medicine focuses on preventing hazards in the internal environment.
Radiation hazards are minimized with shielding.
Poisonous gases such as carbon monoxide and Freon must be monitored and controlled.

Hyperbaric Oxygen Therapy

High-pressure oxygen (hyperbaric oxygen) has therapeutic benefits for:
- Gas gangrene, reducing the risk of death.
- Decompression sickness, arterial gas embolism, carbon monoxide poisoning, osteomyelitis, and myocardial infarction.
Hyperbaric oxygen therapy is administered in pressure tanks, typically at 2 to 3 atmospheres of pressure.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores the effects of pressure on the body during diving, including concepts like Boyle's Law, nitrogen narcosis, and oxygen toxicity. Understand how depth impacts physiological changes and the risks involved in deep-sea diving. Test your knowledge on the principles that govern high-pressure environments.