Samantha

Samantha


 * __ Sickle Cell Anemia __**

|| Anemia is a condition where there is a lack of red blood cells. Sickle-cell anemia is an inherited, life-long disease in which red blood cells form into an abnormal crescent shape. Normal red blood cells have a disc-shaped structure.(figure 1) Sickle-cell anemia is an autosomal disorder that contains extra chromosomes. There should naturally be 23 pairs of chromosomes (including the pair of sex chromosomes). In this disorder, the eleventh pair of chromosomes contains an extra chromosome. This is called a disjunction. That means there are 47 chromosomes instead of 46.(figure 2) || An oxygen-carrying protein differs from the regular hemoglobin by one amino acid. This hemoglobin becomes defective and forms crystal-like structures that change the shape of the blood cells. The cell’s transitions happen in the body’s capillaries, after the oxygen is delivered to other cells.
 * Figure 1
 * Figure 2

These sickle-shaped red blood cells slow blood flow, block small vessels, and cause tissue and organ damage. Less oxygen is delivered to the tissue and organs in the body. Sickle cells also have a shorter life span than normal blood cells. Normal blood cells tend to die after around 120 days, where sickle cells only last up to about 10-20 days. Bone marrow replaces red blood cells, but cannot make new blood cells fast enough to replace the dead cells. Anyone who has the disease or carries the trait is born with it. Homozygous victims have the disease, where heterozygous victims contain the trait. If you are a heterozygous carrier of sickle cell anemia, then you carry the trait to pass down to your offspring, but the symptoms of the disease do not bother you as much. This happens because they produce enough normal hemoglobin that the sickled hemoglobin does not affect them as much. The average life-expectancy is about 42 for males, and 48 for females.
 * __ Symptoms __**
 * Most common: Fatigue (feeling tired or weak)
 * Shortness of breath
 * Headaches
 * Dizziness
 * Coldness in hands and feet
 * Pale skin and mucous membranes
 * Jaundice (yellowish color of the skin or whites of the eyes)

__ Statistics __ Biology: The Dynamics of Life
 * __ Complications of Sickle Cell Anemia __**
 * Hand-Foot Syndrome- Usually in children under the age of four, blood flow becomes blocked in hands and feet
 * Splenic Crisis- The spleen traps red blood cells that should be in the bloodstream. This leads to an enlarged spleen, and anemia
 * Infections- have a harder time fighting infections
 * Acute Chest Syndrome-Life-threatening, infections or sickle cells get caught in the lungs, low oxygen levels
 * Pulmonary Hypertension- Damage to small blood vessels in the lungs, blood pressure raises inside lungs
 * Delayed Growth and Puberty in Children- Shortage of red blood cells causes slower growth
 * Stroke- Causes learning problems, lasting brain damage, long-term disability, paralysis, or death
 * Two forms:
 * Occurs if a blood vessel in the brain is damaged or blocked, occurs more often in children
 * Occurs if a blood vessel in the brain bursts
 * Eye Problems- can block, break open, and cause vessels that carry oxygen-rich blood to the eyes to bleed, causes damage to retinas (tissue in the back of the eyes), could cause blindness
 * Multiple Organ Failure- Rare, but serious, happens when you have a sickle cell crisis that causes at least two organs to stop functioning properly
 * Occurs more often among parts of the world where malaria is more common. People that carry the sickle cell trait are less likely to have severe cases of malaria.
 * Affects about 90,000 to 100,000 Americans
 * Occurs among about 1 out of every 500 African-American births
 * Occurs among about 1 out of every 36,000 Hispanic-American births
 * The trait is carried by about 1 in 12 African Americans
 * __ Referances: __**
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