The human heart has four main valves—two on the left and two on the right. The aortic valve is one of the main valves on the left side of the heart. It is the outflow valve for the left ventricle, which means that it is the valve between the heart and the body. The aortic valve opens when the left ventricle squeezes to pump out blood, and closes in between heart beats to keep blood from going backward into the heart.

The kidneys are a pair of organs located in the back of the abdomen. Each kidney is about 4 or 5 inches long -- about the size of a fist. The kidneys' function are to filter the blood. All the blood in our bodies passes through the kidneys several times a day. The kidneys remove wastes, control the body's fluid balance, and regulate the balance of electrolytes. As the kidneys filter blood, they create urine, which collects in the kidneys' pelvis -- funnel-shaped structures that drain down tubes called ureters to the bladder. Each kidney contains around a million units called nephrons, each of which is a microscopic filter for blood. It's possible to lose as much as 90% of kidney function without experiencing any symptoms or problems.

The management of acute ischemic stroke has advanced greatly over the past 2 decades. New interventions, including intravenous and endovascular treatment strategies, have evolved to recanalize arteries and salvage the ischemic brain. The evolution of interventional approaches to the treatment of acute stroke has been prompted by the limitations of intravenous therapy and intended to extend the treatment window, improve recanalization rates, and subsequently long-term clinical outcomes. The major techniques that have defined the current field of interventional acute stroke management and the relevant past and current data, and ongoing clinical trials on interventional stroke therapy will be reviewed. New issues, such as futile recanalization, and time to microcatheter, will also be discussed.

On the rhythm strip, the QRS might be somewhat taller or wider. One commonly seen type of polymorphic ventricular tachycardia is torsades de pointes. Torsades and other polymorphic VT are advanced rhythms which require additional expertise and expert consultation is advised.

Indications for intervention in patients with a renal artery aneurysm (RAA) include the following [20, 8, 13, 14] : Rupture Symptomatic RAA - Hypertension (from associated renal artery stenosis, refractory to medical management), pain, renal ischemia or infarction secondary to embolization from the aneurysm sac RAAs in females who are pregnant or are contemplating pregnancy Diameter greater than 2 cm Enlarging RAA RAA associated with acute dissection Currently, there is no consensus regarding the size at which an RAA should be repaired in an asymptomatic patient. Experts have recommended RAA repair at diameters ranging from 1.5 to 3 cm, [8] though most suggest 2 cm. Some reports have even suggest that larger asymptomatic saccular aneurysms may be managed expectantly. Note that aneurysm rupture at a diameter of 1.5 cm has been reported. Complete calcification of the wall of the aneurysm sac manifests in about 40% of patients. This was once believed to confer protection against rupture [21] ; however, this belief has since been questioned. [30] Asymptomatic, small (<2 cm in diameter) RAAs do not usually require treatment. One notable exception is an RAA in a woman who is pregnant or contemplating pregnancy. In view of the increased risk of rupture in such cases, even small asymptomatic aneurysms should be repaired in this population. For diagnosis and preinterventional planning, gadolinium-enhanced magnetic resonance angiography (MRA) and computed tomography (CT) angiography (CTA) with three-dimensional (3D) reconstruction have essentially replaced conventional arteriography. Regular follow-up examination with ultrasonography (US) or CT) is recommended in patients who are treated expectantly. Spontaneous cure by thrombosis of small aneurysms has been described. Further refinements in endovascular techniques may allow more RAAs to be treated in this manner. So far, excellent short- and intermediate-term results have been described in the literature [40] ; however, there remains a need for further long-term outcome data.

A nerve transfer is a surgical technique that may be used when a patient has a nerve injury resulting in complete loss of muscle function or sensation. Median to radial transfer. Distal AIN to median recurrent motor branch transfer.

The majority of epileptic seizures are controlled by medication, particularly anticonvulsant drugs. The type of treatment prescribed will depend on several factors, including the frequency and severity of the seizures and the person's age, overall health, and medical history. An accurate diagnosis of the type of epilepsy is also critical to choosing the best treatment. Drug Therapy Many drugs are available to treat epilepsy. Although generic drugs are safely used for most medications, anticonvulsants are one category where doctors proceed with caution. Most doctors prefer to use brand-name anticonvulsants, but realize that many insurance companies will not cover the cost. As a result, it is acceptable to start taking a generic anticonvulsant medication, but if the desired control is not achieved, the patient should be switched to the brand-name drug.

Your body is a brilliant machine with many important parts. Watch movies to learn more

Peritoneal dialysis is a treatment for kidney failure that uses the lining of your abdomen, or belly, to filter your blood inside your body. ... The process of first draining the used dialysis solution and then replacing it with fresh solution is called an exchange.

What damage does atherosclerosis cause? Plaque may partially or totally block the blood's flow through an artery in the heart, brain, pelvis, legs, arms or kidneys. Some of the diseases that may develop as a result of atherosclerosis include coronary heart disease, angina (chest pain), carotid artery disease, peripheral artery disease (PAD) and chronic kidney disease.

A ventricular septal defect (VSD) is an opening or hole in the wall that separates the two lower chambers of the heart. This wall is called the ventricular septum. The hole causes oxygen-rich blood to leak from the left side of the heart to the right side. This causes extra work for the right side of the heart, since more blood than necessary is flowing through the right ventricle to the lungs. The hole is usually closed with surgery. However, in certain situations, your child's cardiologist and surgeon may think it is best to close the hole with a special device. This procedure is done in the heart catheterization lab.

The pain of ovulation can range from a mild twinge to severe discomfort and usually lasts from minutes to hours. It is generally felt on one side of the abdomen and may vary each month, depending on which ovary is releasing the egg during that cycle.

From the moment the baby weight starts to accumulate on our bodies, the scheming begins about how to drop the pounds once the little one arrives. After your baby is born and your days gradually begin to regain somewhat of a routine, it's time to put your ideas into action. If you're not sure exactly how to begin, here are seven proven steps for working your way back to your prepregnancy bod—or better!

Your doctor says your chest pain (angina) is caused by blockages in your heart arteries and that you need to get those blockages taken care of. What are your options? First, it's important to determine what type of angina you have. Different types of angina may need different treatments. Common types of angina are chronic stable angina — a type of angina that occurs when your heart is working hard — and unstable angina, which is new chest pain or chest pain that is getting worse. Other types of angina include variant angina — a rare type of angina caused by a spasm in the coronary arteries — and microvascular angina, which can be a symptom of disease in the small coronary artery blood vessels. Unstable angina is a serious situation and requires emergency treatment. Treatment for unstable angina involves hospitalization with medications to stabilize your condition. Some people with unstable angina may require a procedure called angioplasty (also known as percutaneous coronary intervention), usually combined with the placement of a small metal tube called a stent. In some cases of unstable angina, heart surgery (coronary bypass surgery) may be needed. Generally, if you have mild stable angina that is controlled by medications, you may not need further treatments. If you're experiencing symptoms of chronic stable angina even after taking medications and making lifestyle changes, or if you're at higher risk of serious heart disease, your doctor may recommend angioplasty or coronary bypass surgery. Making a decision on how to treat your angina can be difficult, but knowing the benefits and risks of stents and medications may help you decide.

Systemic circulation carries oxygenated blood from the left ventricle, through the arteries, to the capillaries in the tissues of the body. From the tissue capillaries, the deoxygenated blood returns through a system of veins to the right atrium of the heart.

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.

Traumatic brain injury (TBI) is a nondegenerative, noncongenital insult to the brain from an external mechanical force, possibly leading to permanent or temporary impairment of cognitive, physical, and psychosocial functions, with an associated diminished or altered state of consciousness.

Most people have general anesthesia right before surgery. This means you will be asleep and pain-free. Other kinds of anesthesia, like regional anesthesia or a block, may also be used for this surgery. The tissue to replace your damaged ACL will come from your own body or from a donor. A donor is a person who has died and chose to give all or part of his or her body to help others. Tissue taken from your own body is called an autograft. The two most common places to take tissue from are the knee cap tendon or the hamstring tendon. Your hamstring is the muscle behind your knee. Tissue taken from a donor is called an allograft. The procedure is usually performed with the help of knee arthroscopy. With arthroscopy, a tiny camera is inserted into the knee through a small surgical cut. The camera is connected to a video monitor in the operating room. Your surgeon will use the camera to check the ligaments and other tissues of your knee. Your surgeon will make other small cuts around your knee and insert other medical instruments. Your surgeon will fix any other damage found, and then will replace your ACL by following these steps: The torn ligament will be removed with a shaver or other instruments. If your own tissue is being used to make your new ACL, your surgeon will make a larger cut. Then, the autograft will be removed through this cut. Your surgeon will make tunnels in your bone to bring the new tissue through. This new tissue will be in the same place as your old ACL. Your surgeon will attach the new ligament to the bone with screws or other devices to hold it in place. As it heals, the bone tunnels fill in. This holds the new ligament in place. At the end of the surgery, your surgeon will close your cuts with sutures (stitches) and cover the area with a dressing. You may be able to view pictures after the procedure of what the doctor saw and what was done during the surgery.

Such foods include carrots, eggplant, cauliflower, green beans, broccoli, peppers, onions, lettuce, zucchini, tomatoes, peanuts and walnuts. These foods are generally safe for you to eat at each meal without spiking your blood sugar.

The eyes A close up of a young person's eyes. The eyes are responsible for four-fifths of all the information our brain receives. Here you can find out a bit more about how they work, common problems that affect vision and the work Sightsavers does to treat and prevent avoidable blindness. You can also find out more about the people whose lives have been changed thanks to donations from people like you. How do eyes work? (click image to see enlarged version or click here for text alternative) Graphic of an eye with information about its different parts The images we see are made up of light reflected from the objects we look at. This light enters the eye through the cornea. Because this part of the eye is curved, it bends the light, creating an upside down image on the retina (this is eventually put the right way up by the brain). The retina is a complex part of the eye, but only the very back of it is light sensitive. This part of the retina has roughly the area of a 10p coin, and is packed with photosensitive cells called rods and cones. Cones are the cells responsible for daylight vision. There are three kinds – each responding to a different wavelength of light: red, green and blue. The cones allow us to see images in colour and detail. Rods are responsible for night vision. They are sensitive to light but not to colour. In darkness, the cones do not function at all. How do we see an image? The lens focuses the image. It can do this because it is adjustable – using muscles to change shape and help us focus on objects at different distances. The automatic focusing of the lens is a reflex response and is not controlled by the brain. Once the image is clearly focused on the sensitive part of the retina, energy in the light that makes up that image creates an electrical signal. Nerve impulses can then carry information about that image to the brain through the optic nerve.