Environmental BiophysicsEnvironmental Biophysics

TheThe Interaction of MechanicalInteraction of Mechanical&&

Meteorological Factors With Human BodyMeteorological Factors With Human Body.

Ján JakušJán Jakuš

Physical Factors:Physical Factors: 1. The Effects of Gravity 1. The Effects of Gravity

GravityGravity- (Earth- (Earth))- affects the body with force 1g.- affects the body with force 1g.

Gravity Gravity is responsible for Hydrostatic pressure of is responsible for Hydrostatic pressure of body fluids: body fluids: PPHH = density ( = density (ρρ)). gravity (g. gravity (g)) .height (h .height (h))

-- justjust valid for persons in an upright positionvalid for persons in an upright position

Because a gravityBecause a gravity, the higher blood pressures are , the higher blood pressures are below the heartbelow the heart,, the lower values are above the the lower values are above the heartheart. . The pressure difference caused by gravity is: The pressure difference caused by gravity is: 0.77 mm Hg/ 1 cm of a vertical distance0.77 mm Hg/ 1 cm of a vertical distance

Thus, Thus, in thein the foot arteriesfoot arteries around the anklearound the ankle there isthere is BPBPaa = 180 mmHg, = 180 mmHg, at a level of heartat a level of heart = 100 mmHg, = 100 mmHg,

and in the brain arteriesand in the brain arteries = 70 mmHg. Similarly in = 70 mmHg. Similarly in foot veins BPfoot veins BPv v = 80 mm Hg, at a heart = 0 mmHg, in = 80 mm Hg, at a heart = 0 mmHg, in

brain veins=- 10 mmHg (negative subatmosphericbrain veins=- 10 mmHg (negative subatmospheric))

Blood Pressures under OrthostasisBlood Pressures under Orthostasis

2. Effects of Overloading-2. Effects of Overloading- acceleration, or acceleration, or deceleration. Weightlessness state.deceleration. Weightlessness state.

OverloadingOverloading:: 1. longitudinal- positive1. longitudinal- positive (+ g (+ g )) It is It is directed from directed from top to botomtop to botom, i.e in the opposite way to , i.e in the opposite way to the upward movementthe upward movement

- negative (- g - negative (- g )) It acts It acts fromfrom botom to a topbotom to a top, , in the apposite way to the dow-in the apposite way to the dow-nward movementnward movement

2. transversal2. transversal (acts from (acts from the the back to the chestback to the chest or from or from the chest to backthe chest to back)), in the , in the oppo-site way to the movementoppo-site way to the movement

Positive overloadingPositive overloading ( acts from top to botom( acts from top to botom)) when rocket moves upwards, then + g pushes blood when rocket moves upwards, then + g pushes blood from head to the feet. The signs of brain ischeamia from head to the feet. The signs of brain ischeamia develop (i.e.develop (i.e.whitewhite visionvision-because retinal vessels are -because retinal vessels are poorly supplied, or an poorly supplied, or an unconsciousnessunconsciousness)) Overloa- Overloa-ding + 5g may increase a blood pressure in feet up ding + 5g may increase a blood pressure in feet up to 400 mm Hgto 400 mm Hg)) Protection:Protection: double walled antigravital double walled antigravital dress with compressed air.dress with compressed air.

Negative overloading (- g Negative overloading (- g )) ItIt is directed fromis directed from botom to a top, botom to a top, e.g.during len-e.g.during len-

ding of a rocket, or in the fast elevators moving ding of a rocket, or in the fast elevators moving downwards. Negative - g drives blood from downwards. Negative - g drives blood from feet to feet to headhead, the brain and retinal vessels are overfilled and , the brain and retinal vessels are overfilled and thus symptoms of thus symptoms of red visionred vision appear. appear.

Transversal overloadingTransversal overloading

Humas are able to accept better transversal than longi-Humas are able to accept better transversal than longi-tudinal overloading. This overloading acts either tudinal overloading. This overloading acts either from from thethe chest to back chest to back ( astronauts can keep even ( astronauts can keep even 17g/ per 4 min17g/ per 4 min)), , oror from thefrom the back to chest ( back to chest (16 g / 3 16 g / 3 minmin)). Therefore astronauts keep . Therefore astronauts keep laying positionlaying position both both at start and during lending of the rocketat start and during lending of the rocket

Space siccness-Space siccness- kind of disorder during space mis-kind of disorder during space mis-sion with symptoms (nausea, vomiting, headache, sion with symptoms (nausea, vomiting, headache, etc.etc.))

Weightlessness stateWeightlessness state--becausebecause no gravity no gravity astronauts astronauts may suffer frommay suffer from a loss of minerals(a loss of minerals(decalcificationdecalcification)),, (loss of (loss of muscle tissue (muscle tissue (reduce of body massreduce of body mass)), dehydratation, dehydratation( water ( water

deficiencydeficiency))

33. . Effects of a Low Barometric Effects of a Low Barometric Pressure (HypobariaPressure (Hypobaria))

It happens when one climbs to the altitudes above It happens when one climbs to the altitudes above 3,000- 8,000 m. Composition of air (3,000- 8,000 m. Composition of air (Volume % of Volume % of OO22, N, N22....)) at those levels at those levels does not changedoes not change, but a , but a

total barometric pressure total barometric pressure dropsdrops. Hence, also par-. Hence, also par-tial pressures of Otial pressures of O22, N, N22...... fall downfall down..

Altitude Altitude Barom.PBarom.P POPO2 2 in airin air P0P02 2 in lungs in lungs

(m(m )) (mmHg(mmHg)) ((mmHgmmHg)) (mm Hg(mm Hg))

The Effects of HypoxiaThe Effects of Hypoxia-appears first at altitude of -appears first at altitude of 3,500 m ( appreciable handicap 3,500 m ( appreciable handicap )) and at level of and at level of approx. 6,000m as a serious handicap or colapse . approx. 6,000m as a serious handicap or colapse .

The reason is The reason is acute hypoxiaacute hypoxia (a steep fall of P0 (a steep fall of P022))

Symptoms of hypoxia. The Mountain Disease,Symptoms of hypoxia. The Mountain Disease,AcclimatizationAcclimatization

The signs ofThe signs of chronic hypoxiachronic hypoxia: Breatlessness, : Breatlessness, whirling sensation, dizzeness, nausea, vomiting, tachy-whirling sensation, dizzeness, nausea, vomiting, tachy-cardia, loss of orientation – are typical for the cardia, loss of orientation – are typical for the Mauntain Mauntain Disease Disease

The signs ofThe signs of acute hypoxiaacute hypoxia:: Colabs, Loss of Colabs, Loss of Vigility, Pulmonary Oedema, Death (if no oxygen in tank Vigility, Pulmonary Oedema, Death (if no oxygen in tank ))

AcclimatizationAcclimatization: : is needed for climbers to prevent is needed for climbers to prevent hypoxic symptoms. During 3 weeks of climbing they are hypoxic symptoms. During 3 weeks of climbing they are not allowed to climb very fast,but must take some breaks not allowed to climb very fast,but must take some breaks for two- three days. Hence, hormon ERYTROPOETINE is for two- three days. Hence, hormon ERYTROPOETINE is released from kidneys, and in turn, it stimulates the pro-released from kidneys, and in turn, it stimulates the pro-duction of red blood cells in bone marrow. duction of red blood cells in bone marrow. Thus, hypo-Thus, hypo-xia,caused by hypobaria, is balanced by the rise of red xia,caused by hypobaria, is balanced by the rise of red blood cells, in order to assure a sufficient amount of Oblood cells, in order to assure a sufficient amount of O2 2

for tissuesfor tissues. .

4. Effects of High Water and Air Pressures 4. Effects of High Water and Air Pressures (Hyperbaria(Hyperbaria))

During diving -During diving - ambient pressure of water gra-ambient pressure of water gra-dually rises up by the dually rises up by the 1 atm1 atm ( 760 mmHg ( 760 mmHg )) for for every 10 mevery 10 m of water depht. This pressure com- of water depht. This pressure com-presses the diver´s body, and in order to breath presses the diver´s body, and in order to breath and retain alive, the diver must inhale the com-and retain alive, the diver must inhale the com-pressed air (containing Opressed air (containing O2 2 and/or Heliumand/or Helium)) from from

the tank.the tank.

Decompression DiseaseDecompression Disease Inhalation the compressed air ( 3-4 atmInhalation the compressed air ( 3-4 atm)) from the tank from the tank

balances balances the ambient water pressure. However, because the ambient water pressure. However, because air in tank is under high pressure, this results in a air in tank is under high pressure, this results in a rise of rise of physically dissolvedphysically dissolved N N22, O, O22, CO, CO2 2 in blood plasma. Because in blood plasma. Because

OO22 is consumed, CO is consumed, CO2 2 is removed, just Nis removed, just N2 2 dissolves in the dissolves in the

brain and fat tissues. Thus symptoms of „brain and fat tissues. Thus symptoms of „nitrogen narco-nitrogen narco-sis“sis“ appear. At it diver loses orientation and feel „happy“ appear. At it diver loses orientation and feel „happy“ (as after an alcohol consumption(as after an alcohol consumption)). Problem is when he . Problem is when he wants to return back to see level wants to return back to see level fastlyfastly. Then the symp-. Then the symp-toms of toms of decompression diseasedecompression disease develop. The point is that develop. The point is that NN22 bubbles dissolved in tissues and in blood RELEASE and bubbles dissolved in tissues and in blood RELEASE and

may cause an may cause an nitrogen pulmonary nitrogen pulmonary embolization (i.e.obst-embolization (i.e.obst-ruction of lung and brain vessels by nitrogen bubblesruction of lung and brain vessels by nitrogen bubbles)) and and also a death of diver. Decompression physically resam-also a death of diver. Decompression physically resam-bles to an bles to an opening of bottle with soda,opening of bottle with soda, when bubbles when bubbles escape, escape, because the high air pressure falls to normal one.because the high air pressure falls to normal one.

Signs of Decompression Disease, Signs of Decompression Disease, Treatment, Hyperbaric chamberTreatment, Hyperbaric chamber

- - bad pain in the joints and bones,bad pain in the joints and bones,

- strong itching of the skin,- strong itching of the skin,

- lung and heart disorders with collapse- lung and heart disorders with collapse

- even death - because pulmonary oedema- even death - because pulmonary oedema

How to prevent Decompression Disease?How to prevent Decompression Disease?

- instead of air, tank is filled with Oinstead of air, tank is filled with O22 and Heliumand Helium

- diver must take some breaks when turning back to see diver must take some breaks when turning back to see level (e.g. whe he had dived to 60 m and worked there 30 level (e.g. whe he had dived to 60 m and worked there 30 min, he must care for „physiological decompression“ i.e. min, he must care for „physiological decompression“ i.e. move upwards step by step taking totally 90 min. with move upwards step by step taking totally 90 min. with forceful active hyperventilation during breaks ( Nforceful active hyperventilation during breaks ( N2 2 ))

TreatmentTreatment- Fast Recompression in Hyperbaric Chamber and then Slow Fast Recompression in Hyperbaric Chamber and then Slow

DecompressionDecompression

Hyperbaric Chamber Hyperbaric Chamber && Hyperbaric Hyperbaric OxygenationOxygenation

It is a special device for treatmentIt is a special device for treatment of Decompre-of Decompre-ssion disease, Carbone monoxide poisoning ssion disease, Carbone monoxide poisoning and Clostridialand Clostridial infections ( infections ( Clostridia are bacte-Clostridia are bacte-ria very sensitive to oxygen, which kills themria very sensitive to oxygen, which kills them)). . Air (and 0Air (and 022)) is under high pressure (3- 5 atm is under high pressure (3- 5 atm)). .

Point: Physically dissolved O Point: Physically dissolved O 2 2 and Henry´s and Henry´s

LawLaw