Life on earth has evolved with the gravitational force of 1g. Which of the following statements is true in light of this context (select all that are correct).Each correct answer will score partial points, each incorrect answer will score an equivalent deduction.Group of answer choicesThe removal of the gravitational force will result in a fluid shift towards the lower limb and this contributes to the orthostatic intolerance of early astronauts.To overcome the effect of gravity, giraffes have higher mean arterial pressure at the heart (compared to humans) to ensure perfusion of the head.The pull of gravity generates a fluid column within the body with greater volume towards the lowest point closest to earth.The gravitational force provides load on the musculoskeletal system, and the removal of this force leads to bone and muscle loss.

True or false: When an astronaut is weightless in orbit around Earth, the force of gravity acting on the astronaut is zero.True false question.TrueFalse

The effects of gravity are effectively negated if an object is in free fall.  For example, an object orbiting the Earth experiences an apparent weightlessness known as microgravity.  Because the human body evolved under the influence of Earth's gravity, human physiology undergoes several changes in microgravity environments.  Puffy face syndrome (PFS) occurs when an astronaut's extracellular fluid shifts toward upper body regions, resulting in facial bulging and leg shrinkage.  Elongation of the spinal column also occurs as intervertebral discs (spinal cartilage) decompress, making astronauts up to 6 cm taller.Researchers simulated microgravity-induced spinal elongation on Earth by suspending 50 volunteers by the arms, holding each above the ground in an upright position.  The thickness of each intervertebral disc was measured prior to and following 10 minutes of suspension.  Researchers then compared the percentage change in intervertebral disc thickness to similar measurements recorded in microgravity, as shown in Figure 1.Figure 1  Percentage change in intervertebral disc thicknessIn theory, spinal elongation would also occur in reduced-gravity environments like the surface of the Moon, where the acceleration of gravity is one-sixth that observed on the Earth's surface. Question 45Ignoring any attachments between the spinal discs and vertebrae, how would the maximum force of static friction between these anatomical structures compare for a person standing on the surface of the Moon to a person standing on the surface of the Earth?A.It would be 6 times as great.B.It would be approximately equal.C.It would be 1/6 as great.D.It would be 0.

The effects of gravity are effectively negated if an object is in free fall.  For example, an object orbiting the Earth experiences an apparent weightlessness known as microgravity.  Because the human body evolved under the influence of Earth's gravity, human physiology undergoes several changes in microgravity environments.  Puffy face syndrome (PFS) occurs when an astronaut's extracellular fluid shifts toward upper body regions, resulting in facial bulging and leg shrinkage.  Elongation of the spinal column also occurs as intervertebral discs (spinal cartilage) decompress, making astronauts up to 6 cm taller.Researchers simulated microgravity-induced spinal elongation on Earth by suspending 50 volunteers by the arms, holding each above the ground in an upright position.  The thickness of each intervertebral disc was measured prior to and following 10 minutes of suspension.  Researchers then compared the percentage change in intervertebral disc thickness to similar measurements recorded in microgravity, as shown in Figure 1.Figure 1  Percentage change in intervertebral disc thicknessIn theory, spinal elongation would also occur in reduced-gravity environments like the surface of the Moon, where the acceleration of gravity is one-sixth that observed on the Earth's surface. Question 46Which of the following statements explains the discrepancy between the microgravity data and the laboratory data for the experiment described in the passage?A.In microgravity, gravitational forces were converted to tension.B.In the laboratory setting, the weight of the body still acted on spinal cartilage.C.The mass of the laboratory volunteers did not decrease.D.Laboratory volunteers were not suspended upside-down to account for PFS.

The effects of gravity are effectively negated if an object is in free fall.  For example, an object orbiting the Earth experiences an apparent weightlessness known as microgravity.  Because the human body evolved under the influence of Earth's gravity, human physiology undergoes several changes in microgravity environments.  Puffy face syndrome (PFS) occurs when an astronaut's extracellular fluid shifts toward upper body regions, resulting in facial bulging and leg shrinkage.  Elongation of the spinal column also occurs as intervertebral discs (spinal cartilage) decompress, making astronauts up to 6 cm taller.Researchers simulated microgravity-induced spinal elongation on Earth by suspending 50 volunteers by the arms, holding each above the ground in an upright position.  The thickness of each intervertebral disc was measured prior to and following 10 minutes of suspension.  Researchers then compared the percentage change in intervertebral disc thickness to similar measurements recorded in microgravity, as shown in Figure 1.Figure 1  Percentage change in intervertebral disc thicknessIn theory, spinal elongation would also occur in reduced-gravity environments like the surface of the Moon, where the acceleration of gravity is one-sixth that observed on the Earth's surface. Question 43According to the passage, which of the following changes occurs as an astronaut leaves Earth's surface and enters orbit?A.Coefficient of kinetic friction between the astronaut and nearby objects.B.Astronaut center of mass.C.Astronaut bodily inertia.D.Magnitude of the gravitational force between the astronaut and the spacecraft.

The effects of gravity are effectively negated if an object is in free fall.  For example, an object orbiting the Earth experiences an apparent weightlessness known as microgravity.  Because the human body evolved under the influence of Earth's gravity, human physiology undergoes several changes in microgravity environments.  Puffy face syndrome (PFS) occurs when an astronaut's extracellular fluid shifts toward upper body regions, resulting in facial bulging and leg shrinkage.  Elongation of the spinal column also occurs as intervertebral discs (spinal cartilage) decompress, making astronauts up to 6 cm taller.Researchers simulated microgravity-induced spinal elongation on Earth by suspending 50 volunteers by the arms, holding each above the ground in an upright position.  The thickness of each intervertebral disc was measured prior to and following 10 minutes of suspension.  Researchers then compared the percentage change in intervertebral disc thickness to similar measurements recorded in microgravity, as shown in Figure 1.Figure 1  Percentage change in intervertebral disc thicknessIn theory, spinal elongation would also occur in reduced-gravity environments like the surface of the Moon, where the acceleration of gravity is one-sixth that observed on the Earth's surface. Question 47Provided that the initial velocity in both circumstances is identical, how much longer will an astronaut's vertical jumps last on the surface of the Moon compared to on the surface of the Earth?A.1/6 as longB.1/3 as longC.3 times longerD.6 times longer