Explain the physiological reason(s) for those negative effects.
There are physiological reasons for those negative effects of anemia.  One very apparent reason is the mishaping of the cell in sickle cell anemia.  The misshaping of the cell causes less oxygen to be carried throughout the body.  This causes the body to work harder for oxygen which in turn causes fatigue.
     Another physiological reason for fatigue is not enough energy. Which is caused by the red blood cells inability to take the nutrients through the blood stream to where they need to go.  This makes it so your body doens't get its gas to run which wears down and causes negative effects.