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 cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. The basic function of the cell membrane is to protect the cell from its surroundings. It consists of the phospholipid bilayer with embedded proteins.

Appendicitis is an inflammation of the appendix, a 3 1/2-inch-long tube of tissue that extends from the large intestine. No one is absolutely certain what the function of the appendix is. One thing we do know: We can live without it, without apparent consequences.

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.

Breast augmentation surgery involves using breast implants or fat, referred to as fat transfer breast augmentation, to increase the size of your breasts or restore breast volume that has been lost after weight reduction or pregnancy. Breast augmentation is clinically referred to as augmentation mammaplasty. Breast augmentation can: Increase fullness and projection of your breasts Improve the balance of your figure Enhance your self-image and self-confidence Breast implants may also be used for breast reconstruction after mastectomy or injury.

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.

Human

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.

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.

The term "miniaturization" is widely accepted in our vernacular as a positive step in product development. Reducing components to create less space, product footprint and more affordable medical devices are ongoing objectives for manufacturers today. Jabil strives to integrate new innovative technologies into product design and manufacturing as continual miniaturization of medical devices is a focus of the healthcare thought process. Miniaturization is a constantly moving target. Once a novel, new technology sets a higher bar for miniaturization standards, the next ambitious goal is to achieve an even thinner and smaller device. Industry trends, including minimally invasive surgical devices and home health care delivery, demand more sophisticated medical portable devices and easy-to-use electronics which may not be a core competency of medical device manufacturers.

Blepharitis is an inflammation of the eyelids in which they become red, irritated and itchy and dandruff-like scales form on the eyelashes. It is a common eye disorder caused by either bacteria or a skin condition, such as dandruff of the scalp or acne rosacea. It affects people of all ages. Although uncomfortable, blepharitis is not contagious and generally does not cause any permanent damage to eyesight.

Hemoglobin is the protein molecule in red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues back to the lungs. Hemoglobin is made up of four protein molecules (globulin chains) that are connected together.

If it gets more severe and causes symptoms, your low hemoglobin count may indicate you have anemia. A low hemoglobin count is generally defined as less than 13.5 grams of hemoglobin per deciliter (135 grams per liter) of blood for men and less than 12 grams per deciliter (120 grams per liter) for women.

The timing of the nausea or vomiting can indicate the cause. When appearing shortly after a meal, nausea or vomiting may be caused by food poisoning, gastritis (inflammation of the stomach lining), an ulcer, or bulimia. Nausea or vomiting one to eight hours after a meal may also indicate food poisoning.

Nephrotic syndrome is a kidney disorder that causes your body to excrete too much protein in your urine. Nephrotic syndrome is usually caused by damage to the clusters of small blood vessels in your kidneys that filter waste and excess water from your blood. Nephrotic syndrome causes swelling (edema), particularly in your feet and ankles, and increases the risk of other health problems. Treatment for nephrotic syndrome includes treating the underlying condition that's causing it and taking medications. Nephrotic syndrome can increase your risk of infections and blood clots. Your doctor may recommend medications and dietary changes to prevent these and other complications of nephrotic syndrome.

Laparoscopic use of Palmer's Point

Glycogen storage disease (GSD, also glycogenosis and dextrinosis) is the result of defects in the processing of glycogen synthesis or breakdown within muscles, liver, and other cell types. GSD has two classes of cause: genetic and acquired.

A glucagonoma is a rare tumor of the alpha cells of the pancreas that results in the overproduction of the hormone glucagon. Alpha cell tumors are commonly associated with glucagonoma syndrome, though similar symptoms are present in cases of pseudoglucagonoma syndrome in the absence of a glucagon-secreting tumor.

As a result, the amount of glucose in the blood increases while the cells are starved of energy. Over time, high blood glucose levels damage nerves and blood vessels, leading to complications such as heart disease and stroke, the leading causes of death among people with diabetes.

The average human digestive tract is home to as many as 1,000 species of microorganisms. Most of them are harmless -- or even helpful -- under normal circumstances. But when something upsets the balance of these organisms in your gut, otherwise harmless bacteria can grow out of control and make you sick. One of the worst offenders is a bacterium called Clostridium difficile(C. difficile, or C. diff). As the bacteria overgrow they release toxins that attack the lining of the intestines, causing a condition called Clostridium difficilecolitis.