annularRelated word or term.interdigitateRelated word or term.
List of skin conditionsMany skin conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscles and glands. The major function of this system is as a barrier against the external environment. The skin weighs an average of four kilograms, covers an area of two square metres, and is made of three distinct layers: the epidermis, dermis, and subcutaneous tissue. The two main types of human skin are: glabrous skin, the hairless skin on the p...
Integumentary systemThe integumentary system is the set of organs forming the outermost layer of an animal's body, comprising the skin, hair, scales, feathers, hooves, claws, and nails. It acts as a protective physical barrier between the external environment and the internal environment. Additionally, it maintains water balance, protects the deeper tissues, excretes waste, regulates body temperature, and contains the sensory receptors that detect pain, sensation, pressure, and temperature. The skin (integument) is a composite orga...
MuscleMuscle is a specialised soft tissue, one of the four basic types of animal tissues. There are three types of muscle tissues in vertebrates: skeletal muscle tissue, cardiac muscle tissue, and smooth muscle tissue. Muscle tissue gives skeletal muscles the ability to contract and relax. Muscle tissue contains special contractile proteins called actin and myosin which interact to cause movement. Among many other muscle proteins present are two regulatory proteins, troponin and tropomyosin. Muscle is formed during em...
SkinSkin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different developmental origin, structure and chemical composition. The adjective cutaneous means "of the skin" (from Latin cutis 'skin'). In mammals, the skin is an organ of the integumentary system made up of multiple layers of ectodermaltissue and guards the underlying muscles, bones,...
Organ systemAn organ system is a biological system consisting of a group of organs that work together to perform one or more bodily functions. Each organ has a specialized role in an organism body, and is made up of distinct tissues. HumansThere are 11 distinct organ systems in human beings, which form the basis of human anatomy and physiology. These are the respiratory, digestive and excretory, circulatory, urinary, integumentary, skeletal, muscular, endocrine, lymphatic, nervous, and reproductive systems. There are other ...
Nail (anatomy)A nail is a protective plate characteristically found at the tip of the digits (fingers and toes) of almost all primates (except for marmosets), homologous to the claws in other tetrapod animals. Fingernails and toenails are made of a tough rigid protein called alpha-keratin, a polymer also found in the claws, hooves, and horns of vertebrates. StructureThe nail consists of the nail plate, the nail matrix and the nail bed below it, and the grooves surrounding it. Parts of the nailThe nail matrix is the active tis...
MelanonychiaMelanonychia is a black or brown pigmentation of a nail, and may be present as a normal finding on many digits in Afro-Caribbeans, as a result of trauma, systemic disease, or medications, or as a postinflammatory event from such localized events as lichen planus or fixed drug eruption. There are two types, longitudinal and transverse melanonychia. Signs and symptomsMelanonychia is defined by a darkening of the nail plate that is brown to black; the pigment in question is typically melanin. It can affect one or m...
GlandA gland is a cell or an organ in an animal's body that produces and secretes different substances that the organism needs, either into the bloodstream or into a body cavity or outer surface. A gland may also function to remove unwanted substances such as urine from the body. There are two types of gland, each with a different method of secretion. Endocrine glands are ductless and secrete their products, hormones, directly into interstitial spaces to be taken up into the bloodstream. Exocrine glands secrete their...
DiseaseA disease is a particular abnormal condition that adversely affects the structure or function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical conditions that are associated with specific signs and symptoms. A disease may be caused by external factors such as pathogens or by internal dysfunctions. For example, internal dysfunctions of the immune system can produce a variety of different diseases, including various forms of immunodeficiency, h...
ItchAn itch (also known as pruritus) is a that causes a strong desire or reflex to scratch. Itches have many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response patterns are different. Pain creates a withdrawal reflex, whereas itches lead to a scratch reflex. Unmyelinated nerve fibers for itches and pain both originate in the skin. Information for them is conveyed centrally in two distinct systems that both use the same nerve bundle and spinothalamic tract. Classificati...
NosologyNosology (from Ancient Greek (nosos)'disease' and (-logia)'study of') is the branch of medical science that deals with the classification of diseases. Fully classifying a medical condition requires knowing its cause (and that there is only one cause), the effects it has on the body, the symptoms that are produced, and other factors. For example, influenza is classified as an infectious disease because it is caused by a virus, and it is classified as a respiratory infection because the virus infects and damages c...
Racquet nailIn racquet nails (also known as brachyonychia, nail en raquette, and racquet thumb), the nail plate is flattened, the end of the thumb is widened and flattened, and the distal phalanx is abnormally short. In racquet nails, the width of the nail bed and nail plate is greater than their length. The condition is painless and asymptomatic. Racquet nails usually occur on one or both thumbs, but may appear on all fingers and toes. It may be genetic, inherited as an autosomal-dominant trait, or acquired. Genetic disord...*As an Amazon Associate I earn from qualifying purchases.