Called osseous tissue. Bone is composed of specialized connective tissue (collagen) made up of living bone cells (osteocytes) that are embedded in a hard matrix (framework) of calcified substance. Bone matrix contains collagen fibers and the minerals calcium phosphate and ...

A small white blood cell that plays a major role in defending the body against disease. B lymphocytes or B cells make antibodies that attack bacteria and toxins.

A small white blood cell that plays a major role in defending the body against disease. T lymphocytes or T cells are also called T regulatory cells.  T cells attack body cells themselves when they have been taken over by ...

FoxP3+ T cells represent a major subset of regulatory T cells. They can be produced as natural or induced cells. FoxP3+ T cells are made in the thymus gland as natural FoxP3+ T cells and periphery as induced FoxP3+ T ...

What Is Chronic Dry Eye Syndrome? Chronic dry eye syndrome is an inflammatory condition of the conjunctiva with inadequate tear production or distribution over the eye surface. It is characterized by surface damage to the conjunctiva, giving the appearance of ...

What Is Eczema? Eczema, or atopic dermatitis, is a chronic recurring inflammatory skin disorder characterized by itching, eczematous plaques and a defective epidermal barrier (surface layer of skin cells) that fails to hold moisture, with affected areas becoming dry then inflamed. ...

Glands of the skin or mucous membranes that secrete the substances they produce into ducts leading to a target body surface and ultimately to the outside of the body. Examples are sweat glands in the skin, lacrimal glands in eyelids, ...

What Is Vitamin B12? Vitamin B12, also called cobalamin, is a highly complex vitamin that functions in two coenzyme forms: adenosylcobalamin and methylcobalamin. These forms of the vitamin play important roles in the physical and chemical processes by which amino ...

What Is Muscle Weakness? Muscle weakness is the impaired status of muscle function characterized by decreased or low muscle strength and inability to perform normal work such as lifting a pot off the stove. Q: How do muscles work? A: ...

What Are Cataracts? Cataract is a clouding of the normally clear lens in an affected eye characterized by blurred vision and progressive blindness due to loss of the len’s ability to focus light rays on the retina. Cataracts can occur ...

What Is Intraepithelial Lymphocytosis In Normal Small Bowel Samples? Intraepithelial lymphocytosis is characterized by an abnormal increase in the numbers of intraepithelial lymphocytes (IELs) that are present in the small intestinal mucosa. Q: What are intraepithelial lymphocytes? A: Intraepithelial lymphocytes are ...

What Is Sarcoidosis? Sarcoidosis is a multisystem granulomatous disease characterized by hard granulomas and inflammation of the alveoli in lungs that occurrs in 80% of patients. Alveoli are the tiny one cell thick round structures that are clustered at the ...

What Is Peripheral Neuropathy? Peripheral neuropathy is a syndrome involving damage to one or more peripheral nerves characterized by impaired nerve transmission. Peripheral nerves are nerves of the body outside the brain and spinal cord. Q: Why is nerve transmission impaired? ...

What Is Autism and Learning Disabilities? Autism and learning disabilities constititute a non-progressive psychiatric syndrome appearing in childhood characterized by withdrawal from communication with others often accompanied by repetitive or primitive behaviors. Primary gastrointestinal pathology may play an important role ...

What Are White Spots And White Bands In Nails? White spots in the nails is a feature of zinc deficiency and white bands signify protein deficiency characterized by abnormal appearance anywhere in one or more nails. White spots and bands ...