L4. Aerospace physiology Flashcards
What are the three main physiological challenges of aerospace travel?
Hypoxia, radiation, and microgravity
What is the significance of Boyle’s Law in aerospace physiology?
It explains gas expansion and pressure-volume changes during altitude shifts
How is cabin pressure managed in commercial aircraft?
Cabins are pressurized to mimic altitudes of 5000–8000 ft to balance engineering and physiological needs
What is the typical cabin pressure equivalent in commercial flights?
5000–8000 ft
What are the symptoms of tension pneumothorax in flight?
Severe chest pain, dyspnea, and cardiovascular collapse
What causes hypoxia during air travel?
Reduced oxygen partial pressure at high altitudes
How is hypoxia studied in simulated flight conditions?
By exposing participants to hypoxic conditions in chambers or real flight
What experiment demonstrated ventilatory acclimatization to mild hypoxia?
Fatemian et al showed increased ventilatory sensitivity to hypoxia after 8 hours of exposure
What are the cardiovascular risks for passengers with pre-existing conditions during flights?
Increased risk of pulmonary hypertension and hypoxia-induced stress
What is the role of erythropoietin in response to mild hypoxia?
Stimulates red blood cell production to counteract oxygen deficiency
What are the primary physiological challenges of microgravity?
Vestibular disturbances, fluid redistribution, and muscle and bone atrophy
How is bone loss managed in astronauts during long-duration spaceflights?
Through resistance and weight-bearing exercises
What is the cause of ‘space adaptation syndrome’?
Disruption of balance due to altered gravitational forces
What did the Buckey study reveal about central venous pressure in space?
Central venous pressure decreases contrary to expectations
How do parabolic flights simulate microgravity?
By creating weightlessness during freefall at the top of a parabolic arc
What is the impact of radiation on astronauts during space travel?
Increases risk of cancer and acute radiation syndrome
What findings suggest that age affects pulmonary vascular responses to hypoxia?
Older individuals show greater pulmonary artery pressure rises during hypoxia
What is the role of the vestibular system in space sickness?
Senses acceleration and movement, disrupted in microgravity leading to space sickness
What are the cardiovascular effects of high G-force experienced during suborbital flights?
Increased heart strain, pulmonary pressure, and desaturation
What safety concerns are associated with commercial space tourism?
Loss of consciousness and cardiovascular strain during high G-forces
What experiment demonstrated the increase in pulmonary pressure during commercial flights?
Smith et al showed pulmonary pressure increases even with mild desaturation
How does fluid redistribution in microgravity affect astronauts?
It leads to cephalic fluid shift, causing facial puffiness and nasal congestion
What countermeasures are used to combat muscle atrophy in space?
Treadmill, cycling, and advanced resistance exercise devices
What is the ‘Garn scale’ and what does it measure?
A scale for measuring severity of space adaptation syndrome, named after Senator Jake Garn
What role do hyperbaric chambers play in aerospace physiology research?
They mimic altitude and pressure changes to study physiological responses
How do centrifuge studies simulate the effects of high G-force?
By exposing participants to acceleration profiles similar to those of suborbital flights
What was the outcome of Buckey’s central venous pressure experiments in space?
Central venous pressure decreases unexpectedly in microgravity
How do changes in cephalic fluid shift manifest visually in astronauts?
Engorged veins and puffiness due to lack of gravitational pull
What is ‘Spaceflight Associated Neuro-ocular Syndrome’ (SANS) and its implications?
A syndrome causing optic disc swelling and vision changes, affecting astronauts
What are the challenges of radiation exposure for long-term space missions?
It poses risks of acute syndrome and long-term cancer during Mars missions
How did Tom Smith’s research contribute to understanding hypoxia in flight?
Demonstrated pulmonary artery pressure increase during hypoxia exposure
What findings suggest that pulmonary vascular pressure increases even in mild hypoxia?
Older participants had greater rises in pulmonary pressure compared to younger ones
What safety guidelines are recommended for patients with respiratory diseases planning to fly?
Hypoxic challenge tests to predict in-flight oxygen needs
What was revealed about blood oxygenation during high G-force simulations?
Desaturation to 80% observed under simulated high G and hypoxic conditions
How are suborbital flight profiles simulated for physiological research?
Acceleration profiles recreated using advanced centrifuges
What is the significance of erythropoietin spikes in frequent flyers?
Mild hypoxia triggers erythropoietin increases, potentially impacting frequent flyers
What are the long-term cardiovascular effects of chronic microgravity exposure?
Reduced arterial stiffness and vascular remodeling over long exposure
How does microgravity impact the vestibular system during extended missions?
Causes space sickness, resolved with time and adaptation
What adaptations are essential for reducing radiation risks on Mars missions?
Shielding and mission planning to avoid peak solar radiation events
What are the implications of fluid redistribution for cardiovascular function in space?
Altered venous return and cardiac preload due to lack of gravity
