The pituitary is a small gland (about the size of a kidney bean) located at the base of the brain, just beneath the optic (eye) nerve in a bony area called the sella turcica. It is made up of the anterior (adenohypophysis) and posterior (neurohypophysis) pituitary gland. It is often called the ?master gland? because it produces a number of hormones that regulate other hormone glands in the body. The pituitary is, in turn, regulated by the hypothalamus; a portion of the brain that responds to a variety of nerve and hormonal signals from the environment and the rest of the body.
Anterior pituitary hormones include TSH (thyroid gland), ACTH (adrenal gland), GH (growth hormone), LH and FSH (reproduction) and prolactin (lactation for breast feeding). Posterior pituitary hormones include AHD (water and salt balance) and oxytocin (childbirth).
Pituitary disorders can be due to either too much, or too little pituitary hormone secretion. These disorders can result in a wide variety of different clinical conditions, depending on which hormone signal(s) are disrupted. See below for specific information about different pituitary disorders.
Red blood cells carry oxygen to all parts of your body. They also remove carbon dioxide (a waste product) from your body's cells and carry it to the lungs to be exhaled.
Red blood cells are made in your bone marrow?a sponge-like tissue inside the bones. White blood cells and platelets (PLATE-lets) also are made in your bone marrow. White blood cells help fight infection. Platelets stick together to seal small cuts or breaks on blood vessel walls and stop bleeding.
If you have PV, your bone marrow makes too many red blood cells. It also can make too many white blood cells and platelets.
A mutation, or change, in the body's JAK2 gene is the major cause of PV. This gene makes a protein that helps the body produce blood cells. What causes the change in the JAK2 gene isn't known. PV generally isn't inherited?that is, passed from parents to children through genes.
PV develops slowly and may not cause symptoms for years. The disease often is found during routine blood tests done for other reasons.
When signs and symptoms are present, they're the result of the thick blood that occurs with PV. This thickness slows the flow of oxygen-rich blood to all parts of your body. Without enough oxygen, many parts of your body won't work normally.
For example, slower blood flow deprives your arms, legs, lungs, and eyes of the oxygen they need. This can cause headaches, dizziness, itching, and vision problems, such as blurred or double vision.
