Doctor-Reviewed Health Guides: Conditions, Procedures & Health News

Helper T cells are immune cells that detect infections and coordinate the body's defense. They do not kill pathogens directly but release chemical messengers called cytokines that activate B cells to make antibodies and cytotoxic T cells to fight infection. As central orchestrators of adaptive immunity, they help the body respond to specific threats while protecting healthy tissue.

Glands are specialized epithelial tissues that make and secrete chemicals needed for body processes. Endocrine glands release hormones directly into the blood as long-distance messengers, while exocrine glands deliver substances such as digestive enzymes or sweat through ducts. Found from the brain to the skin, glands regulate metabolism, growth, digestion and body temperature.

Gerota’s fascia, also called the renal fascia, is a tough fibrous envelope surrounding the kidneys, adrenal glands and their protective fat. It anchors these organs, shields them from injury and helps stop localized infections or bleeding from spreading. Made mostly of collagen, it forms a boundary that separates the renal system from other abdominal organs and blood vessels.

Fibrin is a fibrous protein involved in blood clotting, formed from fibrinogen by the enzyme thrombin. It polymerizes into a mesh that creates a plug or clot over a wound. Fibrin is essential for stopping bleeding, aiding wound repair and providing a foundation for new blood vessel growth and tissue regeneration.

Fenestrated capillaries are tiny blood vessels with small pores in their inner endothelial layer that let larger molecules and proteins pass between blood and tissues more easily than standard capillaries. Found mainly in the kidneys, small intestines and endocrine glands, they are essential for filtration, nutrient absorption and hormone distribution. Managing blood pressure and diet helps protect them.

The external iliac vein is a blood vessel in the pelvis that carries oxygen-poor blood from the legs, pubic region and lower front abdominal wall back toward the heart. It begins at the inguinal ligament as a continuation of the femoral vein and joins the internal iliac vein at the sacroiliac joint. Healthy circulation through it helps prevent blood clots.

DNA is a complex molecule found in the nucleus of almost every cell that acts as the body's master instruction manual. It is made of building blocks called nucleotides arranged in a double helix. It stores and transmits genetic information, providing codes to make proteins that drive biological processes. DNA is inherited equally from both biological parents.

A dermatome is an area of skin that relies on a single spinal nerve to transmit signals to and from the brain. Dermatomes cover nearly the whole body except the face and are grouped as cervical, thoracic, lumbar or sacral. Providers use this map to pinpoint spinal cord injuries or nerve compression and guide treatment.

The deltoid ligament is the primary stabilizer on the inside of the ankle, connecting the shinbone to several foot bones in a strong triangular support that prevents excessive inward rotation. Injuries, called medial ankle sprains, typically occur from direct impact or extreme rolling. Strengthening exercises, balance training and supportive gear during high-impact sports help protect it.

Chyle is a cloudy, milky fluid formed in the small intestine during fat digestion, made of lymph combined with chylomicrons that package dietary fats. Because these fats are too large to enter blood capillaries directly, chyle travels through the lymphatic system and thoracic duct into the jugular veins. It also carries proteins and immune cells, supporting nutrition and immunity.

Cholecystokinin (CCK) is a hormone secreted by the small intestine during digestion. It stimulates the gallbladder and pancreas to release bile and digestive enzymes into the duodenum to break down fats and proteins. It also acts as a natural appetite suppressant by slowing stomach emptying and signaling fullness to the brain through the vagal nerves.

Cartilage is a tough, flexible connective tissue that caps the ends of bones and lines joints, absorbing shock and reducing friction, and it shapes the ears, nose and windpipe. Its three types are hyaline, elastic and fibrocartilage. It has no direct blood supply, so it heals slowly. Osteoarthritis is the most common cartilage condition.

Adrenaline is a hormone produced in the adrenal glands, above the kidneys, that prepares the body for stressful or dangerous situations. Its sudden release into the bloodstream, often called an adrenaline rush, increases heart rate, speeds up breathing and redirects blood to the muscles. This fight-or-flight response ensures maximum alertness and physical readiness when facing immediate threats.

Adrenal glands are small, triangle-shaped endocrine organs that sit on top of each kidney. Their outer cortex produces steroid hormones like cortisol and aldosterone, and their inner medulla releases catecholamines such as adrenaline. These hormones are critical for managing stress, regulating blood pressure and maintaining metabolic balance, making proper adrenal function essential for survival.

Adipose tissue is a connective tissue and endocrine organ found throughout the body, including under the skin and around internal organs. It stores and releases energy, provides insulation, cushions soft organs and secretes hormones that regulate hunger, satiety and insulin sensitivity. Too much or too little fat can lead to chronic inflammation and metabolic disease.

An anterior placenta is a normal, harmless placenta position on the front wall of the uterus, present in roughly 48–50% of pregnancies. It does not cause complications or affect the baby. You may feel kicks later and more softly, and finding the heartbeat may take longer. It is seen on routine ultrasound and needs no treatment.

Pleurisy is inflammation of the pleura — the two-layered membrane surrounding the lungs — that causes sharp, stabbing chest pain, especially when breathing deeply, coughing, or sneezing. Causes include viral infections, bacterial infections, autoimmune diseases, and more serious underlying conditions. Treatment depends on the cause but often includes anti-inflammatory medications for pain relief.