Anatomy & Physiology, LEC-NER

Human beings have long been curious about the way that things work, and that curiosity includes wondering about how we ourselves work. The fields of anatomy and physiology involve studying the structures of bodies and the way that those structures and bodies function.
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Anatomy & Physiology Encyclopedia Articles By Title

lecanemab
lecanemab, human monoclonal antibody used for the treatment of Alzheimer disease. Lecanemab clears away and blocks......
lecithin
lecithin, any of a group of phospholipids (phosphoglycerides) that are important in cell structure and metabolism.......
leg
leg, limb or appendage of an animal, used to support the body, provide locomotion, and, in modified form, assist......
lens
lens, in anatomy, a nearly transparent biconvex structure suspended behind the iris of the eye, the sole function......
lens dislocation
lens dislocation, abnormal position of the crystalline lens of the eye. The dislocation, which may be congenital,......
levator muscle
levator muscle, any of the muscles that raise a body part. In humans these include the levator anguli oris, which......
levonorgestrel
levonorgestrel, synthetic progestogen (any progestational steroid, such as progesterone) that is used as a form......
Lewis blood group system
Lewis blood group system, classification of human blood based on the expression of glycoproteins called Lewis (Le)......
ligament
ligament, tough fibrous band of connective tissue that serves to support the internal organs and hold bones together......
limbic system
limbic system, group of structures in the brain that governs emotions, motivation, olfaction (sense of smell),......
lipoprotein
lipoprotein, any member of a group of substances containing both lipid (fat) and protein. They occur in both soluble......
lips
lips, soft pliable anatomical structures that form the mouth margin of most vertebrates, composed of a surface......
liver
liver, the largest gland in the body, a spongy mass of wedge-shaped lobes that has many metabolic and secretory......
loin
loin, that part of an animal lying between the upper part of the hipbone and the last of the false ribs on either......
loop of Henle
loop of Henle, long U-shaped portion of the tubule that conducts urine within each nephron of the kidney of reptiles,......
lorica
lorica, a tubular, conical, or vaselike structure secreted by some protozoans (e.g., Stentor) and many rotifers.......
lucid dreaming
lucid dreaming, phenomenon of sleep in which one is aware that one is dreaming. During lucid dreaming, individuals......
lung
lung, in air-breathing vertebrates, either of the two large organs of respiration located in the chest cavity and......
Lutheran blood group system
Lutheran blood group system, classification of human blood based on the presence of substances called Lutheran......
lymph
lymph, pale fluid that bathes the tissues of an organism, maintaining fluid balance, and removes bacteria from......
lymph node
lymph node, any of the small, bean-shaped masses of lymphoid tissue enclosed by a capsule of connective tissue......
lymph nodule
lymph nodule, small, localized collection of lymphoid tissue, usually located in the loose connective tissue beneath......
lymphatic system
lymphatic system, a subsystem of the circulatory system in the vertebrate body that consists of a complex network......
lymphoblast
lymphoblast, immature white blood cell that gives rise to a type of immune cell known as a lymphocyte. The nucleus......
lymphocyte
lymphocyte, type of white blood cell (leukocyte) that is of fundamental importance in the immune system because......
lymphoid tissue
lymphoid tissue, cells and organs that make up the lymphatic system, such as white blood cells (leukocytes), bone......
macrophage
macrophage, type of white blood cell that helps eliminate foreign substances by engulfing foreign materials and......
macula lutea
macula lutea, in anatomy, the small yellowish area of the retina near the optic disk that provides central vision.......
macular degeneration
macular degeneration, group of blinding disorders that cause the gradual deterioration of the retina in the eye.......
major types of pollinators
Pollination is essential to the perpetuation of the vast majority of the world’s wild plants—and thus the perpetuation......
malpighian tubule
malpighian tubule, in insects, any of the excretory organs that lie in the abdominal body cavity and empty into......
mammary gland
mammary gland, milk-producing gland characteristic of all female mammals and present in a rudimentary and generally......
mandible
mandible, in anatomy, the movable lower jaw, consisting of a single bone or of completely fused bones in humans......
mantle
mantle, in biology, soft covering, formed from the body wall, of brachiopods and mollusks; also, the fleshy outer......
masseter
masseter, (from Greek masasthai, “to chew”), prominent muscle of the jaw. The masseter arises from the zygomatic......
mast cell
mast cell, tissue cell of the immune system of vertebrate animals. Mast cells mediate inflammatory responses such......
mastitis
mastitis, inflammation of the breast in women or of the udder in sheep, swine, and cattle. Acute mastitis in women......
mastoid process
mastoid process, the smooth pyramidal or cone-shaped bone projection at the base of the skull on each side of the......
maternal imagination
maternal imagination, idea that maternal thoughts during pregnancy are transmitted directly to the developing fetus,......
mechanoreception
mechanoreception, ability of an animal to detect and respond to certain kinds of stimuli—notably touch, sound,......
mediastinum
mediastinum, the anatomic region located between the lungs that contains all the principal tissues and organs of......
medulla oblongata
medulla oblongata, the lowest part of the brain and the lowest portion of the brainstem. The medulla oblongata......
medullary thyroid carcinoma
medullary thyroid carcinoma, tumour of the parafollicular cells (C cells) of the thyroid gland. It occurs both......
medusa
medusa, in zoology, one of two principal body types occurring in members of the invertebrate animal phylum Cnidaria.......
melanocyte
melanocyte, specialized skin cell that produces the protective skin-darkening pigment melanin. Birds and mammals......
membrane
membrane, in biology, the thin layer that forms the outer boundary of a living cell or of an internal cell compartment.......
meninges
meninges, three membranous envelopes—pia mater, arachnoid, and dura mater—that surround the brain and spinal cord.......
menopause
menopause, permanent cessation of menstruation that results from the loss of ovarian function and therefore represents......
menstrual cycle
menstrual cycle, recurring fluctuations in hormone levels that produce physical changes in the uterus and ovaries......
menstruation
menstruation, periodic discharge from the vagina of blood, secretions, and disintegrating mucous membrane that......
mesentery
mesentery, a continuous folded band of membranous tissue (peritoneum) that is attached to the wall of the abdomen......
mesoderm
mesoderm, the middle of the three germ layers, or masses of cells (lying between the ectoderm and endoderm), which......
mesomorph
mesomorph, a human somatotype (physical type) that is marked by greater than average muscular development, as determined......
mesonephros
mesonephros, permanent kidney of amphibians and most fish, developing posterior to and replacing the pronephros......
messenger RNA
messenger RNA (mRNA), molecule in cells that carries codes from the DNA in the nucleus to the sites of protein......
metabolomics
metabolomics, the study of metabolites, the chemical substances produced as a result of metabolism, which encompasses......
metacarpal
metacarpal, any of several tubular bones between the wrist (carpal) bones and each of the forelimb digits in land......
metanephros
metanephros, permanent kidney in reptiles, birds, and mammals, developing by the 10th week in human embryos from......
metatarsal
metatarsal, any of several tubular bones between the ankle (tarsal) bones and each of the hindlimb digits, in land......
microglia
microglia, type of neuronal support cell (neuroglia) occurring in the central nervous system of invertebrates and......
microRNA
microRNA (miRNA), small molecule in cells, typically about 21–25 nucleotides in length, that plays a crucial role......
microvillus
microvillus, any of numerous microscopic bristlelike protrusions that occur on the surface of a wide variety of......
midbrain
midbrain, region of the developing vertebrate brain that is composed of the tectum and tegmentum. The midbrain......
middle age
middle age, period of human adulthood that immediately precedes the onset of old age. Though the age period that......
mirror neuron
mirror neuron, type of sensory-motor cell located in the brain that is activated when an individual performs an......
mitosis
mitosis, a process of cell duplication, or reproduction, during which one cell gives rise to two genetically identical......
MNSs blood group system
MNSs blood group system, classification of human blood based on the presence of various substances known as M,......
monoclonal antibody
monoclonal antibody, antibody produced artificially through genetic engineering and related techniques. Production......
mononuclear phagocyte system
mononuclear phagocyte system, class of cells that occur in widely separated parts of the human body and that have......
monosaccharide
monosaccharide, any of the basic compounds that serve as the building blocks of carbohydrates. Monosaccharides......
mons pubis
mons pubis, pad of fatty tissue lying in front of the pubic symphysis. The mons pubis is a rounded eminence made......
morphogenesis
morphogenesis, the shaping of an organism by embryological processes of differentiation of cells, tissues, and......
morula
morula, solid mass of blastomeres resulting from a number of cleavages of a zygote, or fertilized egg. Its name......
mouth
mouth, in human anatomy, orifice through which food and air enter the body. The mouth opens to the outside at the......
mouthbreeder
mouthbreeder, any fish that breeds its young in the mouth. Examples include certain catfishes, cichlids, and cardinal......
mucous membrane
mucous membrane, membrane lining body cavities and canals that lead to the outside, chiefly the respiratory, digestive,......
multiple birth
multiple birth, the delivery of more than one offspring in a single birth event. In most mammals the litter size......
multiple endocrine neoplasia
multiple endocrine neoplasia (MEN), any of a group of rare hereditary disorders in which tumours occur in multiple......
mummy
mummy, body embalmed, naturally preserved, or treated for burial with preservatives after the manner of the ancient......
muscle system, human
human muscle system, the muscles of the human body that work the skeletal system, that are under voluntary control,......
myelin
myelin, white, insulating sheath on the axon of many neurons. Composed of fatty materials, protein, and water,......
myeloblast
myeloblast, immature blood cell, found in bone marrow, that gives rise to white blood cells of the granulocytic......
myelocyte
myelocyte, stage in the development of the granulocytic series of white blood cells (leukocytes) in which granules......
myofibril
myofibril, very fine contractile fibres, groups of which extend in parallel columns along the length of striated......
myoglobin
myoglobin, a protein found in the muscle cells of animals. It functions as an oxygen-storage unit, providing oxygen......
myopia
myopia, visual abnormality in which the resting eye focuses the image of a distant object at a point in front of......
myxedema
myxedema, physiological reaction to lack of sufficient thyroid hormone (hypothyroidism) in the adult. It can be......
nail
nail, in the anatomy of humans and other primates, horny plate that grows on the back of each finger and toe at......
nasal concha
nasal concha, any of several thin, scroll-shaped bony elements forming the upper chambers of the nasal cavities.......
nasal gland
nasal gland, in marine birds and reptiles that drink saltwater, gland that extracts the salt and removes it from......
natural childbirth
natural childbirth, any of the systems of managing parturition in which the need for anesthesia, sedation, or surgery......
navel
navel, in anatomy, a small depression in the abdominal wall at the point of attachment of the umbilical cord (q.v.).......
neck
neck, in land vertebrates, the portion of the body joining the head to the shoulders and chest. Some important......
nematocyst
nematocyst, minute, elongated, or spherical capsule produced exclusively by members of the phylum Cnidaria (e.g.,......
neonatal hypothyroidism
neonatal hypothyroidism, condition characterized by the absence, lack, or dysfunction of thyroid hormone production......
nephridium
nephridium, unit of the excretory system in many primitive invertebrates and also in the amphioxus; it expels wastes......
nephron
nephron, functional unit of the kidney, the structure that actually produces urine in the process of removing waste......
nerve
nerve, in anatomy, a glistening white cordlike bundle of fibres, surrounded by a sheath, that connects the nervous......

Anatomy & Physiology Encyclopedia Articles By Title