Space

Question 1

In space there are a combination of stressful stimuli:
* … forces
* R…
* W…

On Earth there is a … field and a … are major factors that have made Earth able to sustain life. RADIATION, they get ion and proton fluxes more than at earth

links between microgravity, … onset and …

extended duration showed signs of … balance with … loss, muscle …, cardiovascular and hematic changes, m…, endocrine, and … disturbances

What is low orbit? Gravity at ISS?
what causes the weightlessness?

Answer 1

In space there are a combination of stressful stimuli:
* Acceleration forces
* Radiation
* Weightlessnes

On Earth there is a static gravitational field and a protective atmosphere are major factors that have made Earth able to sustain life

links between microgravity, disease onset and aging

extended duration showed signs of negative calcium balance with bone density loss, muscle atrophy, cardiovascular and hematic changes, metabolic, endocrine, and sleep disturbances

low orbit is 200km to 2000km ISS at 400
90% of earths ground level gravity, but the speed during orbit counterbalances the gravity and makes the weightlessness feeling

Question 2

On Earth, fluids shift based on …
In an upright posture. Head is ~70 mmHg. Heart is ~93 mmHg. Feet is ~200 mmHg
In a supine posture. Mean BP for the body is ~… mm

In space this …
… in intrathoracic pressure and blood is redistributed towards the …
Altered responses of …, nervous and … systems.

Within few minutes, “…” includes anorexia, …, …, … and fatigue
These occur because of changes in sensory input to the … system. There is a mismatch between … and … inputs

Unloading of the … in the first few days. Adjusted by … days.

Answer 2

On Earth, fluids shift based on gravity
In an upright posture. Head is ~70 mmHg. Heart is ~93 mmHg. Feet is ~200 mmHg
In a supine posture. Mean BP for the body is ~93 mm

In space this gradient does not occur
Reduction in intrathoracic pressure and blood is redistributed towards the head.
Altered responses of baroreceptor, nervous and endocrine systems.

Within few minutes, “space motion sickness,” includes anorexia, vomiting, nausea, headache and fatigue
These occur because of changes in sensory input to the vestibular system. There is a mismatch between expected and actual inputs

Unloading of the OTOLITH organs in the first few days. Adjusted by 5 days.

Question 3

In the first hours and days. … redistribution causes the … and … to swell as blood moves from the lower limbs. Forehead 7%. Tibia -15%
“…”

Heart … as there is …
… in the first 10 days

Protocol on earth to stimulate changes in physiology during spaceflight = … Recreates …

Answer 3

In the first hours and days. Fluids redistribution causes the head and chest to swell as blood moves from the lower limbs. Forehead 7%. Tibia -15%
“Puffy Head, Chicken Legs.”

Heart doesn’t need to work as hard to push blood as there is no gravity to work against.
Atrophied -8%/-10% in the first 10 days

Protocol on earth to stimulate changes in physiology during spaceflight = 6 degree head down bed rest tilt. Recreates puffy head chicken legs

Question 4

As blood is pushed to the … during microgravity these changes are detected by the … which activate … and … regulation

To COMPENSATE for extra blood in …:

… HR
Reduced level of … / … production.
More blood volume in the head, neck and torso (…).

Once acclimatized, there is a reduced … (increased …)
… and … are maintained at pre-flight levels

The longer you are in space your total blood volume needs to go down. EPO = Hb production goes down.

Answer 4

As blood is pushed to the head during microgravity these changes are detected by the baroreceptors which activate autonomic offloading and BV regulation

To COMPENSATE for extra blood in head:

Reduction HR
Reduced level of thirst / increased urine production.
More blood volume in the head, neck and torso (baroreceptors).

Once acclimatized, there is a reduced total blood volume (increased hematocrit)
MAP and HR are maintained at pre-flight levels

Question 5

In space:
Loss of bone and muscle mass attributed to both … and … changes

The rate of bone mineral density loss during 6-month is similar to someone …

What sites was loss higher? Where was there less?

In space, humans do not need to …, muscles become … (…). The main cause of loss is a decrease in …

how does the Skeletal muscle protein synthesis-to-degradation ration change?

Answer 5

In space:
Loss of bone and muscle mass attributed to both reduced use and perfusion changes

The rate of bone mineral density loss during 6-month is similar to someone 50 to 60 on Earth

Supporting the body sites, lumbar spine, femoral neck, trochanter, pelvic, heel, and leg. Less in the arms

In space, humans do not need to support their bodies, muscles become atrophied (sarcopenia). The main cause of loss is a decrease in muscular activity

how does the Skeletal muscle protein synthesis to degradation ration change?

Question 6

Fluid change at 24hours. 1 month. Landing and 2 days after returning

Vestibular changes. 24 hours. 1 week. landing?

Muscle changes. 24 hours to 1 month. Landing?

Bone demineralization 24 hours to 1 month. 1 year after landing?

Psychological effects. When?

Answer 6

Question 7

Answer 7