Day 7 & 8 quiz 4

Osteoblasts

Bone cells responsible for building up bone tissue.

Osteoclasts

Bone cells responsible for breaking down/resorbing bone tissue.

ARED

Advanced Resistive Exercise Device; the most effective countermeasure for preventing space bone loss by providing heavy weight-bearing axial loads.

Treadmill Running

An inflight exercise that is NOT as effective as ARED because it lacks high-level skeletal resistive loading.

Inflight Bone Monitoring

Using DXA (Dual-energy X-ray Absorptiometry) scans and Ultrasound to track bone density changes.

ASCR

Astronaut Strength, Conditioning and Rehabilitation; the team that runs the postflight reconditioning program starting on landing day.

Sarcopenia

The progressive loss of skeletal muscle mass and strength.

Muscle Atrophy Rate

Astronauts lose roughly 10% to 15% of total muscle mass during a 6-month stay on the ISS.

Antigravity Muscles

Postural muscles (calves/soleus, quads, lower back) that work against Earth's gravity; they experience the most severe atrophy in space.

Cardiac Output Equation

Cardiac Output = Stroke Volume x Heart Rate.

Red Blood Cells (RBCs)

Cells that carry hemoglobin (Hb) with a standard lifespan of 120 days.

Fluid Shift Phenomena

The upward migration of blood and plasma to the head in microgravity, causing headaches in space and orthostatic intolerance on Earth.

Orthostatic Intolerance

Severe dizziness or fainting upon returning to Earth's gravity because blood pools in the lower extremities, reducing oxygen to the brain.

Neurovestibular Conflict

A sensory mismatch where visual inputs conflict with inner ear vestibular signals, causing Space Motion Sickness (SMS).

Dexedrine & Scopolamine

Pharmaceutical medications used to chemically treat and manage Space Motion Sickness.

LBNP

Lower Body Negative Pressure; a physical countermeasure device that uses a vacuum to pull fluids back down into the lower body.

AFT

Autogenic Feedback Training; a behavioral therapy tool used to help astronauts consciously manage motion sickness symptoms.

Neutrophils

Phagocytic immune cells that specifically target and destroy bacteria.

Eosinophils

Phagocytic immune cells that specifically target and destroy parasites.

Basophils

Phagocytic immune cells that mediate allergic reactions and inflammation.

Macrophages

Phagocytic immune cells that engulf large cellular debris and produce cytokines.

B-lymphocytes

Adaptive immune cells that neutralize foreign invaders by producing antibodies.

T-lymphocytes

Adaptive immune cells responsible for coordinating immune combat attacks.

Killer T-cells

Immune cells that liquidate/destroy compromised host cells; spaceflight heavily reduces their action.

ICE Framework

The environmental immune stressors: Isolated, Confined, and Extreme environments.

Viral Reactivation

The awakening of dormant latent viruses (like Shingles or Herpes) due to spaceflight stress and immune suppression.

Eleutherococcus (Ellogen)

A Siberian tree root extract used by Russian cosmonauts to boost immune function and stress resistance.

Demyelination

The stripping away of the protective myelin sheath off nerve fibers caused by space radiation exposure.

Cataractogenesis

The radiation-induced formation of cataracts that cloud the lens of the eye.

GCR & SPE

Galactic Cosmic Rays and Solar Particle Events; the primary sources of deep space radiation.

RBE

Relative Biological Effectiveness; a ratio measuring the specific biological tissue damage caused by different radiation particles.

ARS

Acute Radiation Syndrome; severe illness caused by receiving a massive toxic dose of radiation over a very short period.

Osteoradionecrosis

Bone cell death and tissue loss induced explicitly by high radiation exposure.

Scott Kelly Study

NASA twin study showing a permanent 7% difference in gene expression and DNA shifts following a year in space.

Career Radiation Limit

The maximum lifetime radiation exposure allowed for an astronaut, which is set at 600 mSv.

SRAG

Space Radiation Assessment Group; the group that monitors astronaut flight radiation doses using Matroshka phantoms and dosimeters.

Polyethylene

A lightweight, hydrogen-rich plastic polymer that is highly effective at shielding against space radiation.

AstroRAD

A specialized protective vest worn by astronauts that utilizes polyethylene shielding.

Shielding Power Hierarchy

Weakest to strongest protection: Paper, Skin, Metal, Water, Concrete, Lead.

Aggregation of Marginal Gains

The philosophy that integrating many small, diverse physiological countermeasures results in an effective total defense strategy.