Erythropoiesis - regulation
How does thyroxine affect erythropoiesis?
It stimulates more release of EPO from the kidney.
Polycythemia
Increased number of erythrocytes and hemoglobin in the blood. Makes the blood too thick and increases risk of tissues not receiving adequate blood supply. Also increases risk of stroke.
What stimulates the kidneys to release EPO?
Low blood volume testosterone thyroxine
Why does hypothyroidism cause anemia?
Thyroxine normally stimulates erythropoiesis through stimulating EPO. Deficient thyroxine means not enough new red blood cells are made.
Sickle Cell Anemia
a genetic disorder that causes abnormal hemoglobin, resulting in some red blood cells assuming an abnormal sickle shape. These inflexible cells get stuck in capillaries and cause mini-strokes.
symptoms of anemia
fatigue (not enough oxygen to cells to make ATP) paleness (lack of RBCs makes someone look paler) short breath (breathing more rapidly to bring in more oxygen) cold (lack of quantity of blood, which helps keep the body warm)
Erythropoietin (EPO)
hormone secreted by the kidney to stimulate the production of red blood cells by bone marrow
Blood doping
inject extra red blood cells before competition to improve performance
What organ releases EPO?
kidneys
pernicious anemia
lack of mature RBCs caused by lack of intrinsic factor, a stomach enzyme required for Vitamin B12 absorption. Now understood to be an autoimmune disease where antibodies bind to the intrinsic factor, making it unable to help B12 be absorbed.
Anemia word meaning
"no blood"
Anemia common causes
*iron deficiency *Vitamin B12 deficiency (often caused by pernicious anemia) *sickle cell disease - mutation in hemoglobin *hypothyroidism *occult "hidden" bleeding (internal bleeding of the colon, for example) *bone marrow stem cell damage (aplastic anemia)
aplastic anemia
characterized by an absence of all formed blood elements caused by the failure of blood cell production in the bone marrow. Usually caused by autoimmunity, radiation, chemicals, or cancer
