Ménière’s disease A condition that is characterized by recurrent vertigo accompanied by ringing in the ears (tinnitus) and deafness. Symptoms include vertigo, dizziness, nausea, vomiting, loss of hearing in the affected ear, and abnormal eye movements. Ménière’s disease is due to dysfunction of the semicircular canals (endolymphatic sac) in the inner ear. Treatment usually includes…
Mendelian inheritance The manner by which genes and traits are passed from parents to their children. The modes of Mendelian inheritance are autosomal dominant, autosomal recessive, X-linked dominant, and X-linked recessive. Also known as classical or simple genetics.
Mendelian Referring to Gregor Mendel or his theories.
Mendel, Gregor The father of genetics, the Moravian/Bohemian biologist who in the 19th century set forth the basic laws that constitute the foundation of classical genetics. Mendel’s controlled experiments with breeding peas in the monastery garden led him to conclude that the heritable units (now called genes) were not blends of parental traits, but rather…
menarche The time in a girl’s life when menstruation first begins. During the menarche period, menstruation may be irregular and unpredictable. Also known as female puberty.
memory span The number of items, usually words or numbers, that a person can retain and recall. Memory span is a test of working memory (short-term memory). In a typical test of memory span, an examiner reads a list of random numbers aloud at about the rate of one number per second. At the end…
memory B cells Secondary immune-system components that have an affinity for a particular antigen. Like other B cells, memory B cells originate from lymphocytes that develop and are activated in the bone marrow.
memory, short-term The ability to temporarily store and manage information that is required to carry out complex cognitive tasks such as learning, reasoning, and comprehension. Short-term memory is involved in the selection, initiation, and termination of information-processing functions, such as encoding, storing, and retrieving data. One test of short-term memory is memory span: the number…
memory, retrograde Memory for things prior to an event or brain injury. The opposite of anterograde memory.
memory, long-term The ability to permanently store, manage, and retrieve information for later use. Items of information stored as long-term memory may be available for a lifetime.
memory, anterograde Memory for things following an event or brain injury. The opposite of retrograde memory.
memory The ability to recollect information about past events or knowledge, and/or the process of doing so. Memory is often divided into short-term (also known as working, or recent, memory) and long-term memory: Short-term memory recovers memories of recent events, and long-term memory is concerned with the more distant past. Some medical disorders, such as…