Physics on the Human Body
Christian
(Christian equalizing)

Eustachian Tubes:
The human body is made up of approximately 70% water.  However, there are also cavities of air within the human body.  One of these is known as the eustachian tubes, which are passages that run between the throat and the middle ear.  At the start of a dive, the air pressure within the eustachian tubes is equal to the atmospheric pressure at sea level.  As the diver descends, the air within the eustachian tubes expands, causing an increase in pressure.  Too much pressure in the eustachian tubes can cause middle and inner ear damage, therefore, a diver must equalize the pressure within the eustachian tube to match the pressure at the depth he or she is at.  In order to do this a diver will hold his/her nose, close their mouth and blow; this is known as the valsalva method.  It acts by opening the eustachian tubes in the throat which releases the excess pressure.  If a diver is unable to equalize a condition known as "ear squeeze" will occur.  At this point it is very important that the diver return to the surface immediately. 

Nitrogen Narcosis:
Nitrogen narcosis is caused by the increase in solubility of gases due to increased pressures at increased depths; also known as Henry's Law.  Briefly, Henry's law states, the deeper the depth, the more the human body will absorb gases.  The body is absorbing nitrogen at increasing rates.  Below is a table of depths with their cooresponding signs and symptoms.

Depth (m)

Depth (ft)

Comments

10--30

33-100

Mild impairment of performance of unpracticed tasks.                           Mildly impaired reasoning.                                                                    Mild euphoria possible.

30-50

100-165

Delayed response to visual and auditory stimuli.                                  Reasoning and immediate memory affected more than motor coordination.  Calculation erros and wrong choices.                                                     Idea fixation.                                                                                       Over-confidence and sense of well being.                                         Laughter and ioquacity(in chambers) which may be overcome by self control.  Anxiety (common in cold murky water).

50-70

165-230

Sleepiness, impaired judgement, confusion.                               Hallucinations.                                                                                  Severe delay in response to signals, instructions, and other stimuli.  Occasional dizziness.                                                                         Uncontrolled laughter, hysteria(in chamber).                                         Terror in some. 

70-90

230-300

Poor concentration and mental confusion.                                  Stupefaction and some decrease in dexterity and judgment.                     Loss of memory, increased excitability.

90+

300+

Hallucinations.                                                                             Increased intensity of vision and hearing.                                            Sense of impending blackout, euphoria, dizziness, manic or depressive states, a sense of levitation, disorganization of the sense of time, changes in facial appearance.                                                           Unconsciousness.                                                                            Death.
(Wikipedia)

Decompression Sickness:
Decompression sickness, also known as the bends is caused by going from a high pressure environment to a low pressure one.  Essentially it is the opposite of the nitrogen narcosis.  Since your body has absorbed gases it now needs to expell them slowly.  If you ascend too quickly it doesn't give your body enough time to release the absorbed gases and will cause bubbles in your bodily tissues.  While the bubbles can form anywhere in the body, they are more frequently found to be in the shoulders, elbows, knees and ankles.  Below is a table with the type of bends, where it is located and the symptoms.

DCS Type

Bubble Location

Signs and Symptoms

Bends

Mostly large joints of the body (elbows, shoulders, hip, wrists, knees, ankles?

Localized deep pain, ranging from mild (a "tingle) to excruciating; sometimes a dull ache, but rarely a sharp pain.                    Active and passive motion of the joint aggravates the pain.       The pain may be reduced by bending the joint to find more comfortable position.                                                                 If cause by altitude, pain can occur immediately of up to many hours later.

Skin Bends

Skin

Itching usually around the ears, face,neck, arms, and upper torso.                                                                             Sensation of tiny insects crawling over the skin.                      Mottled or marbled skin usually around the shoulders, upper chest and abdomen, with itching.                                              Swelling of the skin, accompanied by tiny scar-like skin depressions

 

Brain

Confusion or memory loss.                                           Headache.                                                                        Spots in visual field, tunnel vision, double vision, or blurry vision.  Unexplained extreme fatigue or behaviour changes.            Seizures, dizziness, vertigo, nausea, vomiting and unconsciousness may occur, mainly due to labyrinthitis.

Neurological

Spinal Cord

Abnormal sensations such as burning, stinging, and tingling around the lower chest and back.                                  Symptoms may spread from the feet up and maybe be accompanied by ascending weakness or paralysis.                    Girdling abdominal or chest pain.

 

Peripheral Nerves

Urinary incontinence and fecal incontinence.                          Abnormal sensations such as numbness, burning, stinging and tingling.                                                                          Muscle weakness or twitching.

 

Inner Ear (the staggers)

Loss of balance.                                                                 Extreme vertigo.                                                                Hearing loss.

Chokes

Lungs

Burning deep chest pain (under sternum).                               Pain is aggravated by breathing.                                    Shortness of breath.                                                              Dry constant cough.

 (Wikipedia)
Buoyancy        Pressure        Gas Laws        Human Body
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