Space and microgravity Flashcards
Microgravity less than 24 hours after launch
10% reduction in leg fluid volume
Back pain
Neurovestibular alterations cause space motion sickness
17%decrease in plasma volume
Stages of deconditioning?
Mild- reduced physical capability during intense exercise
Moderate- reduced physical activity during normal daily activities
Severe- reduced capability to complete essential daily tasks
Up to 1 month after launch…
Muscle mass decrease by >20% Strength decrease by 50% altered motor control 60-70% calcium loss and reduced parathyroid hormone and vit D Space anaemia Bone density reduced 1-2% per month Psychological stress Impaired immunity
On return to earth…
2 days after landing fluid volume replaced
Muscle soreness, fatigue and stiffness
Motor control problems improve
Improved immune function
Recovery of muscles mass/strength takes 2 months
Bone= > 1 year
Skeletal system following exposure to microgravity
External forces decreased Bone sympathies is reduced Bone architecture and composition modifed to accommodate the new lower load conditions Altered calcium metabolism Reduced bone strength
Effects of fluid shift towards head after entering microgravity
Increased urine output Decreased thirst Decreased heart mass due to deconditioning as less blood to pump Lower metabolic demands Decreased RBC production Decreased SV
Effects of microgravity of vestibular system
Can cause space motion sickness
Extreme distortion
Altered perception of body orientation and equilibrium
Possibly caused by altered vestibular function in the inner ear
Vestibular adaptation in microgravity
Vestibular apparatus adapts within a few days
Countermeasure to onset of motion sickness
General effects of space flight on human muscles
Atrophy and weakness ( mainly affecting postural muscles and extensors more than flexors
Greater neuromuscular inhibition of extensor muscles
A sense of reflex activation
Countermeasures to combat effects of microgravity
Load bearing exercise
