The thyroid is a butterfly-shaped gland that sits low on the front of the neck. Your thyroid lies below your Adam’s apple, along the front of the windpipe. The thyroid has two side lobes, connected by a bridge (isthmus) in the middle. When the thyroid is its normal size, you can’t feel it.

The brain is that part of the CNS contained within the cranial cavity (figure 13.1). It is the control center for many of the body's functions. The brain is much like a complex central computer but with additional functions that no computer can as yet match. Indeed, one goal in computer technology is to make computers that can function more like the human brain. The brain consists of the brainstem, the cerebellum, the diencephalon, and the cerebrum (table 13.1). The brainstem includes the medulla oblongata, pons, midbrain, and reticular formation. The structure of the brain is described in this chapter. Its functions are primarily discussed in chapter 14. Twelve pairs of cranial nerves, which are part of the PNS, arise directly from the brain. Two pairs arise from the cerebrum, nine pairs arise from the brainstem, and one pair arises from the spinal cord.

When is endoscopy used? Endoscopes were first developed to look at parts of the body that couldn’t be seen any other way. This is still a common reason to use them, but endoscopy now has many other uses too. It’s often used in the prevention, early detection, diagnosis, staging, and treatment of cancer. To prevent and screen for cancer Some types of endoscopes are used to look for cancer in people who have no symptoms. For example, colonoscopy (KO-lun-AH-skuh-pee) and sigmoidoscopy (SIG-moid-AH-skuh-pee) are used to screen for colon and rectal cancer. These procedures can also help prevent cancer because they let doctors find and remove polyps (growths) that might become cancer if left alone. To find cancer early Endoscopy can sometimes be used to find cancer early, before it has had a chance to grow or spread. Looking for causes of symptoms When people go to the doctor with certain symptoms, endoscopy can sometimes be used to help find a cause. For instance: Laryngoscopy to look at the vocal cords in people with long-term hoarseness Upper endoscopy in people having trouble swallowing Colonoscopy in people with anemia (low red blood cell counts) with an unknown cause Colonoscopy in people with blood in their stool Looking at problems found on imaging tests Imaging tests such as x-rays and CT scans can sometimes show physical changes within the body. But these tests may only give information about the size, shape, and location of the problem. Doctors use endoscopes to see more details, like color and surface texture, when trying to find out what’s going on. Newer methods of endoscopy that include high magnification are being tested to find out whether they are more useful in detecting cancer and other abnormal cells on the inner surfaces of the body. To diagnose and find out the stage (extent) of cancer To get a tissue sample Going one step further, most types of endoscopes have tools on the end that the doctor can use to take out small tissue samples. This procedure is called a biopsy (BY-op-see). Samples can be taken from suspicious areas and then looked at under a microscope or tested in other ways to see if cancer is there. A biopsy is usually the best way to find out if a growth or change is cancer or something else. Getting a closer look In some cases endoscopes are used to help find out how far a cancer has spread. Thoracoscopy (THOR-uh-KAHS -kuh-pee) and laparoscopy (LAP-uh-RAHS-kuh-pee) can be very useful in finding out if cancer has spread into the thorax (chest) or abdomen (belly). The surgeon can look into these places making only a small incision (cut) in the skin.

HIV stands for human immunodeficiency virus. If left untreated, HIV can lead to the disease AIDS (acquired immunodeficiency syndrome). Unlike some other viruses, the human body can’t get rid of HIV completely. So once you have HIV, you have it for life. HIV attacks the body’s immune system, specifically the CD4 cells (T cells), which help the immune system fight off infections. If left untreated, HIV reduces the number of CD4 cells (T cells) in the body, making the person more likely to get infections or infection-related cancers. Over time, HIV can destroy so many of these cells that the body can’t fight off infections and disease. These opportunistic infections or cancers take advantage of a very weak immune system and signal that the person has AIDS, the last state of HIV infection. No effective cure for HIV currently exists, but with proper treatment and medical care, HIV can be controlled. The medicine used to treat HIV is called antiretroviral therapy or ART. If taken the right way, every day, this medicine can dramatically prolong the lives of many people with HIV, keep them healthy, and greatly lower their chance of transmitting the virus to others. Today, a person who is diagnosed with HIV, treated before the disease is far advanced, and stays on treatment can live a nearly as long as someone who does not have HIV.

Your body's immune system protects you from disease and infection. But if you have an autoimmune disease, your immune system attacks healthy cells in your body by mistake. Autoimmune diseases can affect many parts of the body. No one is sure what causes autoimmune diseases. They do tend to run in families. Women - particularly African-American, Hispanic-American, and Native-American women - have a higher risk for some autoimmune diseases. There are more than 80 types of autoimmune diseases, and some have similar symptoms. This makes it hard for your health care provider to know if you really have one of these diseases, and if so, which one. Getting a diagnosis can be frustrating and stressful. Often, the first symptoms are fatigue, muscle aches and a low fever. The classic sign of an autoimmune disease is inflammation, which can cause redness, heat, pain and swelling. The diseases may also have flare-ups, when they get worse, and remissions, when symptoms get better or disappear. Treatment depends on the disease, but in most cases one important goal is to reduce inflammation. Sometimes doctors prescribe corticosteroids or other drugs that reduce your immune response.

Stomach acid is natural, a valuable chemical contributor to orderly digestion. But in excess or in the wrong place, it's a menace, inflaming and irritating the esophagus, typically causing heartburn and sometimes contributing to the development of ulcers in the stomach and the duodenum, the first part of the small intestine.

Management of postpartum hemorrhage at vaginal delivery. The approach to treatment of postpartum hemorrhage (PPH) differs somewhat depending on the cause and whether hemorrhage occurs after a vaginal birth or after a cesarean delivery.

This hormone, insulin, causes the liver to convert more glucose into glycogen (this process is called glycogenesis), and to force about 2/3 of body cells (primarily muscle and fat tissue cells) to take up glucose from the blood through the GLUT4 transporter, thus decreasing blood sugar.

What does the placenta do? The placenta is an organ that develops in your uterus during pregnancy. This structure provides oxygen and nutrients to your growing baby and removes waste products from your baby's blood. The placenta attaches to the wall of your uterus, and your baby's umbilical cord arises from it. In most pregnancies, the placenta attaches at the top or side of the uterus.

What factors should I consider when deciding whether to have surgery? The following factors should be considered when deciding whether to have surgery: Your age—If you have surgery at a young age, there is a chance that prolapse will recur and may possibly require additional treatment. If you have surgery at an older age, general health issues and any prior surgery may affect the type of surgery that you have. Your childbearing plans—Ideally, women who plan to have children (or more children) should postpone surgery until their families are complete to avoid the risk of prolapse happening again after corrective surgery. Health conditions—Any surgical procedure carries some risk, such as infection, bleeding, blood clots in the legs, and problems related to anesthesia. Surgery may carry more risks if you have a medical condition, such as diabetes, heart disease, or breathing problems, or if you smoke or are obese. New problems—Surgery also may cause new problems, such as pain during sex, pelvic pain, or urinary incontinence.

A semen analysis, also called "seminogram" evaluates certain characteristics of a male's semen and the sperm contained therein. It is done to help evaluate male fertility, whether for those seeking pregnancy or verifying the success of vasectomy

A bulla is a fluid-filled sac or lesion that appears when fluid is trapped under a thin layer of your skin. It’s a type of blister. Bullae (pronounced as “bully”) is the plural word for bulla. To be classified as a bulla, the blister must be larger than 0.5 centimeters (5 millimeters) in diameter. Smaller blisters are called vesicles.

A man set to become the world’s first head transplant patient has scheduled the procedure for December 2017. Valery Spiridonov, 30, was diagnosed with a genetic muscle-wasting condition called Werdnig-Hoffmann disease, and volunteered for the procedure despite the risks involved, Central European News (CEN) reported. “When I realized that I could participate in something really big and important, I had no doubt left in my mind and started to work in this direction,” Spiridonov, a Russian computer scientist, told CEN. “The only thing I feel is the sense of pleasant impatience, like I have been preparing for something important all my life and it is starting to happen.”

To understand high blood cholesterol (ko-LES-ter-ol), it helps to learn about cholesterol. Cholesterol is a waxy, fat-like substance that’s found in all cells of the body. Your body needs some cholesterol to make hormones, vitamin D, and substances that help you digest foods. Your body makes all the cholesterol it needs. However, cholesterol also is found in some of the foods you eat. Cholesterol travels through your bloodstream in small packages called lipoproteins (lip-o-PRO-teens). These packages are made of fat (lipid) on the inside and proteins on the outside. Two kinds of lipoproteins carry cholesterol throughout your body: low-density lipoproteins (LDL) and high-density lipoproteins (HDL). Having healthy levels of both types of lipoproteins is important. LDL cholesterol sometimes is called “bad” cholesterol. A high LDL level leads to a buildup of cholesterol in your arteries. (Arteries are blood vessels that carry blood from your heart to your body.) HDL cholesterol sometimes is called “good” cholesterol. This is because it carries cholesterol from other parts of your body back to your liver. Your liver removes the cholesterol from your body.

A ureteral stent is a thin, hollow tube that is placed in the ureter to help urine pass from the kidney into the bladder. Ureters are the tubes that connect the kidneys to the bladder. You may have a small amount of blood in your urine for 1 to 3 days after the procedure.

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.

Oral sex is a commonly performed act of foreplay involving the kissing or licking of the genital area to pleasure a partner. However, it is sometimes stated that the act alone can increase the risk of throat cancer. Is this really the case?

Given the success of drugs to treat erectile dysfunction, such as sildenafil (Viagra), tadalafil (Cialis) and vardenafil (Levitra), drug companies have sought a comparable drug for women. Viagra has even been tried as a treatment for sexual dysfunction in women. However, the Food and Drug Administration (FDA) hasn't approved this use of Viagra. Indeed, until recently there were no FDA-approved drugs for treating sexual arousal or sexual desire problems in women. Yet 4 in 10 women report having sexual concerns. A prescription medication known as flibanserin (Addyi) — originally developed as an antidepressant — has been approved by the FDA as a treatment for low sexual desire in premenopausal women. A daily pill, Addyi may boost sex drive in women with low sexual desire and who find the experience distressing. Potentially serious side effects include low blood pressure, dizziness and fainting, particularly if the drug is mixed with alcohol. Experts recommend that you stop taking the drug if you don't notice an improvement in your sex drive after eight weeks.

Pancreatic cysts are saclike pockets of fluid on or in your pancreas, a large organ behind the stomach that produces hormones and enzymes that help digest food. Most pancreatic cysts aren't cancerous, and many don't cause symptoms. They're typically found during imaging testing for another problem. Some are actually noncancerous (benign) pockets of fluids lined with scar or inflammatory tissue, not the type of cells found in true cysts (pseudocysts). But some pancreatic cysts can be or can become cancerous. Your doctor might take a sample of the pancreatic cyst fluid to determine if cancer cells are present. Or your doctor might recommend monitoring a cyst over time for changes that indicate cancer.

A distal radius fracture almost always occurs about 1 inch from the end of the bone. The break can occur in many different ways, however. One of the most common distal radius fractures is a Colles fracture, in which the broken fragment of the radius tilts upward. This fracture was first described in 1814 by an Irish surgeon and anatomist, Abraham Colles -- hence the name "Colles" fracture.