Space physiology Flashcards
What occurs to the lungs during high g-forces?
- diaphragm pulled down
- blood also shifted to lower lung
- air stays in upper lung
- little to no gas diffuses across membrane
- therefore, blood cannot be oxygenated properly
What happens to the cardiovascular system during high g-forces?
- fluids pulled down towards the legs
- decreased cardiac output (because decreased venous return)
- can cause tissue ischemia
Explain what occurs when tissue ischemia is happening
- first symptoms are visual (retina is O2 dependent)
- tunnel vision
- full ischemia can can total blindness temporarily
- can either cause relative or absolute incapacitation
How do fighter pilots overcome effects of high g -forces?
AGSM
- forceful contractions of legs and abdominal muscles
- simultaneous pushing pf air out of lungs against a closed glottis
this prevents blood from pooling in lower body away from brain as well as maintaining pressure in carotid artery
- anti gravity trousers (infate at high g-forces)
Why does puffy face happen in space?
- fluids not pulled down by gravity anymore
What are some symptoms of dealing w weightlessness in space?
- puffy face
- weight bearing bones deteriorate
- eyes become main way to sense motion
- space sickness
What causes space sickness?
- conflicting information received by brain from eyes, inner ears and limbs
- organs shifting in microgravity
fluid shifting - dehydration due to kidneys signalling for fluid elimination
What occurs to blood volume in space?
Launch - 10% water loss in legs
24h - activation of renin-angiotensin system (15-20% loss in blood volume)
48h - additional 10% loss in blood volume
What are some long term effects of weightlessness in space?
- anemia
- smaller heart
- increased secretion of ANP
- reduced blood volume
- distended right atrium
- loss of 20% of slow-twitch fibres in fast twitch fibres
