Growth plate Health Dictionary

A product of the anterior part of the PITUITARY GLAND that promotes normal growth and development in the body by changing the chemical activity in the cells. The hormone activates protein production in the muscle cells as well as the release of energy from the metabolism of fats. Its release is controlled by the contrasting actions of growth-hormone releasing factor and somatostatin. If the body produces too much growth hormone before puberty GIGANTISM results; in adulthood the result is ACROMEGALY. Lack of growth hormone in children retards growth.

For many years growth hormone was extracted from human corpses and very rarely this caused CREUTZFELDT-JAKOB DISEASE (CJD) in the recipients. The hormone is now genetically engineered, so safe.... growth hormone

A popular term applied to any new formation in any part of the body. (See CANCER; CYSTS; GANGLION; TUMOUR.) For growth of children, see WEIGHT AND HEIGHT.... growth

Any of various chemicals involved in stimulating new cell growth and maintenance.

Some growth factors, such as vascular endothelial growth factor, which stimulates the formation of new blood vessels, are important in the growth and spread of cancers.... growth factor

The smallest type of blood cell, also called a thrombocyte. Platelets play a major role in blood clotting.... platelet

Platelets are the small, rather uniform fragments of large bone marrow cells that aid the blood in coagulation, hemostasis, inflammation, and thrombus formation. Mild subclotting and sticking is a common early condition that can lead to thrombosis, atherosclerosis, and strokes, and can be helped by an aspirin a day, better fat digestion, and Ceanothus.... platelet aggregation

Blood platelets, or thrombocytes, are small spherical bodies in the BLOOD, which play an important part in the process of its COAGULATION. Normally, there are around 300,000 per cubic millimetre of blood.... platelets

The clumping together of platelets (small, sticky blood particles). Aggregation is the 1st stage of blood clotting and helps to plug injured vessels. Inappropriate aggregation can have adverse effects; for example, if aggregation occurs in an artery, it may result in a thrombosis.... aggregation, platelet

The increase in height and weight as a child develops. The period of most rapid growth occurs before birth. After birth, although growth is still rapid in the first few years of life, especially in the first year, the rate of

growth steadily decreases. Puberty marks another major period of growth, which continues until adult height and weight are reached, usually at about age 16–17 in girls and 19–21 in boys.

Body shape changes during childhood because different areas grow at different rates. For example, at birth, the head is already about three quarters of its adult size; it grows to almost full size during the first year. Thereafter, it becomes proportionately smaller because the body grows at a much faster rate.

Growth can be influenced by heredity and by environmental factors such as nutrition and general health. Hormones also play an important role, particularly growth hormone, thyroid hormones, and, at puberty, the sex hormones.

A chronic illness, such as cystic fibrosis, may retard growth. Even a minor illness can slow growth briefly, although the growth rate usually catches up when the child recovers. In some cases, slow growth may be the only sign that a child is ill or malnourished, in which case it is known as failure to thrive. However, short stature does not necessarily indicate poor health. Abnormally rapid growth is rare. Usually, it is a familial trait, but it may occasionally indicate an underlying disorder, such as a pituitary gland tumour causing gigantism. (See also age; child development.)... growth, childhood

Poor growth in a fetus, usually resulting from a failure of the placenta to provide adequate nutrients (often related to pre-eclampsia) or sometimes from a fetal defect. Severe maternal disease, such as chronic kidney failure, can reduce fetal growth. Fetal problems such as an intrauterine infection or genetic disorder can also impair growth. Smoking during pregnancy may reduce fetal growth and birth weight.

Intrauterine growth retardation may be suspected on antenatal examination;... intrauterine growth retardation

a group of *growth factors that promote new bone formation. Bone morphogenic protein (BMP), a naturally occurring substance that induces *osteoblast formation, has been genetically synthesized to form bone morphogenetic protein, which stimulates new bone formation and assists with fracture healing. Other bone growth factors include a type of transforming growth factor (TGF?) and insulin-like growth factor II (IGF-II), which encourage collagen formation.... bone growth factors

see ethmoid bone.... cribriform plate

n. the area of muscle cell membrane immediately beneath the motor nerve ending at a *neuromuscular junction. Special receptors in this area trigger muscular contraction when the nerve ending releases its *neurotransmitter.... end-plate

(EGFR) a protein on the surface of cells (see receptor) that binds with epidermal *growth factor and is therefore involved in cell division. EGFR is expressed at increased levels in numerous tumours, particularly of the head and neck, and in colorectal cancer, in which it can be a target for antibody therapy with *cetuximab. *Tyrosine kinase inhibitors acting specifically on the EGFR include gefitinib and erlotinib in lung and pancreatic cancer.... epidermal growth factor receptor

a graph, customized to a pregnant woman’s height, weight, and other factors, that plots *fundal height and estimated fetal weight on ultrasound against weeks of gestation. The graph, which shows centile lines (see centile chart), improves prediction of a baby who is *small for gestational age.... fetal growth chart

see intrauterine growth restriction.... fetal growth restriction

(IUGR, fetal growth restriction) failure of a fetus to achieve its growth potential, resulting in the birth of a baby whose birth weight is abnormally low in relation to its gestational age (see small for gestational age). Causes include *uteroplacental insufficiency, maternal disease (e.g. infection, malnutrition, high blood pressure, smoking, and alcoholism), poor socioeconomic conditions, multiple pregnancy (e.g. twins), and fetal disease or chromosomal abnormalities. It may be associated with *preterm birth.... intrauterine growth restriction

(NGF) a protein (see growth factor), consisting of two polypeptide chains, that is required for the development and longevity of some neurons, including those in the sympathetic nervous system and some central nervous system and sensory neurons. Nerve growth factor is necessary for axon growth and also for initiating new neuronal connections with other cells. The role of NGFs in preventing the degeneration of brain cells is being explored in research into Alzheimer’s disease.... nerve growth factor

the strip of ectoderm lying along the central axis of the early embryo that forms the *neural tube and subsequently the central nervous system.... neural plate

the process whereby platelets adhere to collagen released from endothelial cells in damaged blood vessels and aggregate to form a plug. An important metabolic pathway in platelets converts membrane phospholipids to *thromboxane A2 (TXA2), which can activate platelets. ADP, released from platelet granules, and *thrombin are other activators. The adhesive and aggregation reactions of platelets are mediated through surface membrane glycoproteins (Glp), Glp Ib and Glp IIb/IIIa. Aspirin acts as an *antiplatelet drug by irreversibly inhibiting one of the enzymes of this pathway, cyclo-oxygenase. Clopidrogel inhibits the ADP receptor on platelet membranes, and *abciximab blocks platelet aggregation by inhibiting Glp IIb/IIIa (see illustration overleaf).... platelet activation

(PDGF) see growth factor.... platelet-derived growth factor

(TGF) a protein – a *cytokine – that controls growth, proliferation, and other functions in most cells. It plays a role in asthma and other respiratory diseases and is also involved in diseases elsewhere in the body. There are two classes: TGF-? and TGF-?.... transforming growth factor

(VEGF) a *growth factor made by both normal cells and their abnormal or malignant counterparts to stimulate new blood vessel formation (see angiogenesis). It can be targeted by a family of drugs known as *angiogenesis inhibitors, which include *bevacizumab.... vascular endothelial growth factor