The spleen, a spongy, soft organ about as big as a person’s fist, is located in the upper left part of the abdomen, just under the rib cage. The splenic artery brings blood to the spleen from the heart. Blood leaves the spleen through the splenic vein, which drains into a larger vein (the portal vein) that carries the blood to the liver. The spleen has a covering of fibrous tissue (the splenic capsule) that supports its blood vessels and lymphatic vessels. The spleen is made up of two basic types of tissue, each with different functions: White pulp Red pulp The white pulp is part of the infection-fighting (immune) system. It produces white blood cells called lymphocytes, which in turn produce antibodies (specialized proteins that protect against invasion by foreign substances). The red pulp filters the blood, removing unwanted material. The red pulp contains other white blood cells called phagocytes that ingest microorganisms, such as bacteria, fungi, and viruses. It also monitors red blood cells, destroying those that are abnormal or too old or damaged to function properly. In addition, the red pulp serves as a reservoir for different elements of the blood, especially white blood cells and platelets (cell-like particles involved in clotting). However, releasing these elements is a minor function of the red pulp.

Dehydration can also be a cause of kidney stones. A common symptom is having a lower left abdominal pain, fever, nausea, groin pain and vomiting. Lower left abdominal pain can also be caused by an infection of the kidneys. It usually begins with the bladder and then reaches out to the kidneys.

Upper right quadrant: The right upper quadrant contains the liver and gallbladder, which are protected by the lower right part of the ribcage. The large intestine, or colon, also spends a little time in this section. Upper left quadrant: The left upper quadrant contains part of the stomach and the spleen.

This could be caused by an infection, food poisoning, parasites, Crohn's disease, or reduced blood flow in the colon. Hemorrhoids are another common cause of GI or rectal bleeding. A hemorrhoid is an enlarged vein in your rectum or anus. These enlarged veins can rupture and bleed, causing rectal bleeding.

Neurogenic shock is a distributive type of shock resulting in low blood pressure, occasionally with a slowed heart rate, that is attributed to the disruption of the autonomic pathways within the spinal cord. It can occur after damage to the central nervous system such as spinal cord injury.

Hodgkin's lymphoma — formerly known as Hodgkin's disease — is a cancer of the lymphatic system, which is part of your immune system. In Hodgkin's lymphoma, cells in the lymphatic system grow abnormally and may spread beyond the lymphatic system. As Hodgkin's lymphoma progresses, it compromises your body's ability to fight infection. Hodgkin's lymphoma is one of two common types of cancers of the lymphatic system. The other type, non-Hodgkin's lymphoma, is far more common. Advances in diagnosis and treatment of Hodgkin's lymphoma have helped give people with this diagnosis the chance for a full recovery. The prognosis continues to improve for people with Hodgkin's lymphoma.

Menopause is the end of menstruation. In clinical terms, you reach menopause when you haven't had a period for 12 months. Vaginal bleeding after menopause isn't normal and should be evaluated by your doctor. For instance, postmenopausal vaginal bleeding can be caused by: Cancer of the uterus, including endometrial cancer and uterine sarcoma Cancer of the cervix or vagina Thinning of the tissues lining the uterus (endometrial atrophy) or vagina (vaginal atrophy) Uterine fibroids Uterine polyps Infection of the uterine lining (endometritis) Medications such as hormone therapy and tamoxifen Pelvic trauma Bleeding from the urinary tract or rectum Excessive overgrowth of the cells that make up the lining of the uterus (endometrial hyperplasia) The cause of your bleeding may be entirely harmless. However, postmenopausal bleeding could result from something serious, so it's important to see your doctor promptly.

The protein inside red blood cells (a) that carries oxygen to cells and carbon dioxide to the lungs is hemoglobin (b). Hemoglobin is made up of four symmetrical subunits and four heme groups. Iron associated with the heme binds oxygen.

The liver also detoxifies chemicals and metabolizes drugs. As it does so, the liver secretes bile that ends up back in the intestines. The liver also makes proteins important for blood clotting and other functions. First, for those impatient, short answers to the mini-questions (if you're reading this in the news feed, you may want to click through for the question details): No one knows why we evolved 2 kidneys and one liver.

Radiosurgery: Radiosurgery devices, such as the CyberKnife Robotic Radiosurgery System, offer patients a new option for the treatment of lung cancer. The CyberKnife® System is used to treat lung cancer patients who cannot tolerate surgery, have an inoperable tumor, or are seeking an alternative to surgery.

Cancer, also called malignancy, is an abnormal growth of cells. There are more than 100 types of cancer, including breast cancer, skin cancer, lung cancer, colon cancer, prostate cancer, and lymphoma. Symptoms vary depending on the type. Cancer treatment may include chemotherapy, radiation, and/or surgery.

The cornea occupies the front center part of the outer wall of the eye. It is made of collagen fibers in a very special arrangement so that the cornea is clear. One looks through the cornea to see the iris and pupil. The cornea bends light coming into the eye so that it is focused on the retina.

During surgery to repair the hernia, the bulging tissue is pushed back in. Your abdominal wall is strengthened and supported with sutures (stitches), and sometimes mesh. This repair can be done with open or laparoscopic surgery. You and your surgeon can discuss which type of surgery is right for you.

Spermatogenesis is the process in which spermatozoa are produced from spermatogonial stem cells by way of mitosis and meiosis. The initial cells in this pathway are called spermatogonia, which yield primary spermatocytes by mitosis.

The cat's stomach is a sac-like structure designed to store large volumes of food and continue the digestive process. The esophagus carries food to the stomach, where it enters via a valve-like structure called the cardiac sphincter. On the interior surface of the stomach is a series of folds called gastric folds. These folds function to help grind and digest food. The inner stomach lining secretes acids and enzymes to break down food. Once the initial stomach digestive process is complete, the partially digested food exits the stomach through the pyloric sphincter area and then enters the duodenum (first segment of the small intestine). Once eaten, most food leaves the stomach within twelve hours after entering.

If you are self-conscious because you have missing teeth, wear dentures that are uncomfortable or don't want to have good tooth structure removed to make a bridge, talk to your dentist to see if dental implants are an option for you. Dental implants are a popular and effective way to replace missing teeth and are designed to blend in with your other teeth. They are an excellent long-term option for restoring your smile. In fact, the development and use of implants is one of the biggest advances in dentistry in the past 40 years. Dental implants are made up of titanium and other materials that are compatible with the human body. They are posts that are surgically placed in the upper or lower jaw, where they function as a sturdy anchor for replacement teeth.

Cosmetic iris implants have not been evaluated by any U.S. regulatory agency or tested for safety in clinical trials. While the implants are not approved by the U.S. Food and Drug Administration, it has been reported in the media this month that the surgery is being performed overseas. During iris implant surgery, an artificial iris made of silicone is folded and inserted into a slit that has been cut into the cornea. Then the iris is unfolded and adjusted to cover the natural iris. Local anesthesia is used.

Knee osteotomy is commonly used to realign your knee structure if you have arthritic damage on only one side of your knee. The goal is to shift your body weight off the damaged area to the other side of your knee, where the cartilage is still healthy. When surgeons remove a wedge of your shinbone from underneath the healthy side of your knee, the shinbone and thighbone can bend away from the damaged cartilage. Imagine the hinges on a door. When the door is shut, the hinges are flush against the wall. As the door swings open, one side of the door remains pressed against the wall as space opens up on the other side. Removing just a small wedge of bone can "swing" your knee open, pressing the healthy tissue together as space opens up between the thighbone and shinbone on the damaged side so that the arthritic surfaces do not rub against each other. Osteotomy is also used as an alternative treatment to total knee replacement in younger and active patients. Because prosthetic knees may wear out over time, an osteotomy procedure can enable younger, active osteoarthritis patients to continue using the healthy portion of their knee. The procedure can delay the need for a total knee replacement for up to ten years.

Cancer immunology is a branch of immunology that studies interactions between the immune system and cancer cells (also called tumors or malignancies). It is a growing field of research that aims to discover innovative cancer immunotherapies to treat and retard progression of the disease.

Elbow. In primates, including humans, the elbow joint is the synovial hinge joint between the humerus in the upper arm and the radius and ulna in the forearm which allows the hand to be moved towards and away from the body.