专业术语—口腔生理学术语M3(英文详解)-医务英语

Morphogenic fieled - an environment in which the shape or pattern of a developing organ is determined.

Motoneurone - nerve cells with their cell bodies in the brain stem or spinal cord, which transmit impulses along their axons to effector organs, including endocrine, exocrine glands and muscles fibres. The axons of most motoneurones have many branches, each of which ends at a neuromuscular junction. The group of muscle cells innervated by one motoneurone is called a motor unit.

Mucoperiosteum - a type of oral mucosa which has a fibrous lamina propria, no submucosa, and is attached to the underlying periosteum of bone. The attached gingiva is a mucoperiosteum.

Mucous - a secretion which is viscous and slimy due to the presence ofglycoproteins.

Mutation - a change in the order of nucleotide bases on a gene, which alters the configuration of the protein produced, and thus may alter the behaviour of the cell. A mutation may cause a cell to die, or become cancerous. Mutations in bacteria and viruses help them to evade detection by their hosts.

Myelin - the fatty covering of myelinated nerves which appears white to the naked eye. The parts of the brain and spinal cord, in which myelinated nerves run, has therefore been called the "white" matter as distinct from the "grey" matter composed of nerve cells. Myelin also contains about 20 % of proteins whose prime role is to mediate adhesion between adjacent Schwann cells. These cell membrane glycoproteins are also members of the immunoglobulin family of cell surface proteins. Defects in the these surface proteins may cause them to act as antigens to the immune system. The disease multiple sclerosis is caused by antibodies to the myelin proteins, which results in inflammation and loss of myelin.

Myelinated - nerves axons which are completely wrapped in a sheath of myelin by schwann cells. One cell wraps about a millimetre of nerve axon. Myelinated nerve axons carry impulses faster then unmeyelinated nerves as the impulse jumps across the myelin sheath of each adjacent Schwann cell to that of the next.