what is the pressure of air at sea level?

one atmostphere or 760mmhg

what is boyles law?

the volume of any gas varies invesely with the pressure on it.

if it pressure doubles. the volum will /2

what is hygrostatic pressure?

weight of a column of water directly above the body, it will increase with the depth of water.

it will increase by every 33ft .by 1 atmosphere

what are the limits to snorkeling? explain them

pressure effects; you can only go down 3 ft. because the compressive force of water against the chest cavity is so large that the inspiration muscles are unable to over come the external pressure and expand the thoracic cavity.

increase in pulmonary dead space; V_{A =} V_T - V_D

EXPLAIN BREATH HOLD DIVING

what is normal max breath holding?

- as diver descends, the air in the lungs are compressed -- the lungs squeeze.

--- this means... lung will become damanged. because blood is sucked from the pulmonary capillaries into the alveoli.

50-60scds

what happens if you hyperventilate prior to breath holding?

it can extend the time significantly. but its dangerous because you can blackout.

if you do it for one minute . it can decrease PaCo2 to 30mmhg

what is paradoxical drowning?

diver hyperventilates --- hold breaths -- dives down -- gases in the lung compress and partical pressures are increased--- partial pressues in the lng decrease on ascent -- pao2 decreases below a critical point -- drives loose conciousness and drowns

what is scuba ?

what are the equipment that you need when you scuba dive?

self contained underwater breathing apparatus

1. you need: mask and snorkle
2. clothing - wet suit
3. weight belt
4. buoyancy compensator
5. tank and backpack
6. depth gauge and pressure gauge
7. single hose, two stage regulator
   

why do you need a tank?

to overcum the force of water against the drivers chest

what are potential problesm associated with scuba diving?

air embolism

pneumothorax - lung collapse

nitrogen carcosis

the bends

o2 poisoining

mask squeeze

middle ear squeeze

what is a air embolism?

air that enters and obstrucs a blood vessel

driver inflates lungs and begins to go down --> he doesnt exhale --> pressure decreases as he ascends -< air in alveoi expands too a point they rupture --> air bubble enters blood vessels --> blocks artery in heart --> death . possibly

what is a rule of scuba diving?

dont hold ur breath

what happens when ur lung collapse while down there?

what else is it called ?

pneumothorax

ruptured alveoli --> air pocket forms outside the lungs btw the chest wall and lung tissue --> continued expansion of trapped air during ascents = rupture to lungs to collapse

what is nitrogen narcosis?

@ depths over 100ft -- partial pressure and quantity increase and dissove N. creates an anesthetic effect on CNS. similar to alcohol... decrease awareness.

what is the bends ?

what is its alias?

" decompression sickenss"

ascend to the surface to rapidly after a prolonged dive, dissolved N moves out of solution and forms bubbles in body tissue and fluids.

where do you first feel the pain in the bends?

around joint within 4-6hrs after diving

if you have a bubble lodged in an artery? permanent damnage or death will occur

how can you treat and prevent the bends?

t: recompression in a hyperbaric chamber to force the N gas back into solution then slow the decompression

p: ascend to the suface in stages.

what is oxygen poisoning?

what are its effects?

happens then the inspired Po2 exceeds 1520 mmhg for loner than 30-60 mins

effects are

1. muscle twitching
2. confusion
3. nausea
4. convulsions

what is mask squeeze?

happens when you go down water. its a pressure difference between two structures

mask should cover whole face. so the pressue is equal inside and out.

what is middle ear squeeze?

eustachian tube -- small membrane lined passage connecting the middle ear to the throat..

maintains equilibirum within the ear cavity and the outside air. by tranfering air to or from the lungs.

pain in the ear after only going down a few feet.