Deficiency of hemoglobin in the blood.

Multiple causes:

1. Too few RBC's

2. Too little hemoglobin

Rapid hemorrhage causes fluid loss.

Plasma is replaced in 1 to 3 days, but RBC levels take 3 to 6 weeks to recover.

In chronic blood loss state, body cannot absorb enough iron from intestines to replace iron lost from bleeding.

Defined by RBC's that have too little hemoglobin inside them. Microcytic and Hypochromic anemia,

Bone marrow aplasia.

 BM is not function appropriately.

Can be caused by radiation, chemicals (benzene) or drugs.

Poor absorbtion or lack of Vitamin B₁₂, folic acid or intrinsic factor from stomach mucosa can lead to slow reproduction of erythroblasts in bone marrow.

Results in large cells w/ odd shapes = megaloblasts

Often seen in patients atrophy or loss of stomach mucosa OR poor vitamin absorption. Cell membranes rupture easily.

Many abnormalities, mostly genetic, lead to membranes easily rupturing. Rupture usually occurs in capillaries or spleen.

hereditary spherocytosis RBC's are round instead of bi-concave discs, cannot withstand deformation and burst.

sickle cell anemia hypoxic state induces crystal formation inside RBC causing cell to take sickle shape and eventually rupture

erythoblastosis fetalis caused by Rh+ fetal cells being attacked by an Rh- mother antibodies. Can cause fetus to die.

Decreased blood viscosity. Reduces peripheral resistance/increases blood flow & cardiac output.

Hypoxic state causes vessel dilation. Increases flow and CO again. (3-4x normal)

Increased CO can overcome resting loss of O₂ from anemia, but cannot increase to a level to compensate for exercise. Exercise can lead to acute cardiac failure in anemic individuals.

Polycythemia Vera (Erythremia)

Secondary Polycthemia

Poly = many

Cyth (Cyte) = Cell

Emia = Blood

Increase in cells in the blood.

Induced from hypoxic state (high altitude, poor oxygen delivery, cardiac failure).

Blood forming organs immediately increase RBC production. RBC count = 6-7 million/mm3 or 30% above normal levels.

physiologic polycythemia  seen in those living at high altitudes (14-17,000 feet)

Pathologic condition. RBC count around 7-8 million/mm3 and hematocrit is 60-70% instead of 40-45% in normal state.

Caused by genetic aberration in growth factor sensativity. Blasts continually divide despite no phsyiologic need.  Can cause blood volume to nearly double. Leads to increased viscosity from 3x water to 10x  water. Causes capillaries to plug with viscous blood.

Decreased velocity of blood through periphery from increased viscosity. Leads to decreased venous return, but increased blood volume can compensate so CO is about normal.

2/3 have normal peripheral pressure with 1/3 being elevated.

Skin venous beds are engorged with slow moving blood. Blood becomes heavily deoxygenated and individuals look cyanotic.