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.

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.

Root canals are common procedures and can help save your tooth from extraction. Dentists at Aspen Dental practices have been safely and expertly performing root canal procedures for over two decades.

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HIV gradually destroys the immune system by attacking and killing a type of white blood cell called a CD4 cell. CD4 cells play a major role in protecting the body from infection. HIV uses the machinery of the CD4 cells to multiply (make copies of itself) and spread throughout the body. This process, which is carried out in seven steps or stages, is called the HIV life cycle. HIV medicines protect the immune system by blocking HIV at different stages of the HIV life cycle. Antiretroviral therapy or ART is the use of HIV medicines to treat HIV infection. People on ART take a combination of HIV medicines from at least two different HIV drug classes every day. Because each class of drugs is designed to target a specific step in the HIV life cycle, ART is very effective at preventing HIV from multiplying. ART also reduces the risk of HIV drug resistance. ART can’t cure HIV, but HIV medicines help people with HIV live longer, healthier lives. ART also reduces the risk of HIV transmission (the spread of HIV to others).

Shoulder dystocia is a rare emergency that can happen during the end of the second stage of labour. It's all to do with how your baby moves down through your vagina and out into the world. Shoulder dystocia happens when your baby's head has been born, but one of her shoulders becomes stuck.

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.

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.

A heart attack is a frightening, confusing and stressful experience. Life after a heart attack isn’t easy, but we’re with you all the way on your journey toward recovery. Here you will find information about heart attack warning signs, risk factors, diagnosis, treatment, and life as a survivor or caregiver. You will also find heart attack tools and resources to help you get and stay healthy.

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If it is not removed, tooth decay will begin. The acids in plaque damage the enamel covering your teeth. It also creates holes in the tooth called cavities. Cavities usually do not hurt, unless they grow very large and affect nerves or cause a tooth fracture.

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.

Wound healing is the process by which skin or other body tissue repairs itself after trauma. ... This process is divided into predictable phases: blood clotting (hemostasis), inflammation, tissue growth (proliferation) and tissue remodeling (maturation).

A tracheotomy or a tracheostomy is an opening surgically created through the neck into the trachea (windpipe) to allow direct access to the breathing tube and is commonly done in an operating room under general anesthesia. A tube is usually placed through this opening to provide an airway and to remove secretions from the lungs. Breathing is done through the tracheostomy tube rather than through the nose and mouth. The term “tracheotomy” refers to the incision into the trachea (windpipe) that forms a temporary or permanent opening, which is called a “tracheostomy,” however; the terms are sometimes used interchangeably.

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.

Lipomas are slow-growing soft tissue tumours that rarely reach a size larger than 2 cm. Lesions larger than 5 cm, so-called giant lipomas, can occur anywhere in the body but are seldom found in the upper extremities. The authors present their experiences with eight patients having giant lipomas of the upper extremity. In addition, a review of the literature, and a discussion of the appropriate evaluation and management are included.

Papillary fibroelastoma is the third most common primary tumor of the heart and is most likely to involve the cardiac valves. Like myxomas, they arise from the endocardium in most patients and since these tumors are often incidental findings at echocardiography or autopsy, the true incidence is difficult to estimate. Most patients are older than 60 years, which also contrasts with myxomas. Papillary fibroelastomas can embolize, leading to severe neurological complications and therefore, surgical removal is advised, although there is controversy regarding small incidental lesions and the need for surgery.

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.

Pulmonary circulation is the portion of the cardiovascular system which carries deoxygenated blood away from the heart, to the lungs, and returns oxygenated (oxygen-rich) blood back to the heart. The function of pulmonary circulation is to exchange carbon dioxide for oxygen in the blood. It is the passage of blood from the heart to the capillaries of the lungs, where the gases are exchanged, and back to the heart to be pumped around the body.

The hepatic portal system is the system of veins comprising the hepatic portal vein and its tributaries. It is responsible for directing blood from the region of the gastrointestinal tract between the esophagus and rectum and also includes venous drainage from the supplementary organs such as the spleen and pancreas.