PRINCIPLES OF TOXICOLOGY - Biology East Borneo

568 GLOSSARYoral route The entry of a chemical into the body by way of the gastrointestinal tract. Althoughabsorption to some extent takes place throughout the tract, the majority of the absorption takesplace in the area of the villi of the small intestine.organic acid Any acid, the radical of which is a carbon derivative; a compound in which ahydrocarbon radical is joined to COOH (carboxylic acid) or to SO 3H (sulfonic acid).organochlorine pesticides These compounds are extremely stable and persistent in the environment.They are efficiently absorbed by ingestion, and act on the central nervous system to stimulate ordepress it. Signs and symptoms of toxicity vary with the specific chemical. In general, mildpoisoning cases cause symptoms such as dizziness, nausea, abdominal pain, and vomiting. Inchronic poisoning, weight loss and loss of appetite, temporary deafness, and disorientation canoccur.organophosphate pesticides These are irreversible inhibitors of cholinesterase, thus allowingaccumulating of acetylcholine at nerve endings. They are rapidly absorbed into the body byingestion, through intact skin, including the eye, and by inhalation. Poisoning symptoms rangefrom headache, fatigue, dizziness, vomiting, and cramps in mild cases, to the rapid onset ofunconsciousness, local or generalized seizure, and other manifestations of a cholinergic crisis insevere cases.osteomalacia A condition of softening of the bones characterized by pain, tenderness, loss of weight,and muscular weakness.osteoporosis Abnormal rarefaction of bone, seen most commonly in the elderly.osteosclerosis Hardening or abnormal density of bone.ototoxic Having a toxic effect on the structures of the ear, especially on its nerve supply.pancytopenia A form of anemia in which the capacity of the bone marrow to generate red bloodcells is defective. This anemia may be caused by bone marrow disease or exposure to toxic agents,such as radiation, chemicals, or drugs.paraffin A class of aliphatic hydrocarbons characterized by a straight or branched carbon chain afidhaving the generic formula C n H 2n+2 ; also called alkane.paranoid schizophrenia A psychotic state characterized by delusions of grandeur or persecution,often accompanied by hallucinations.parasympathetic Craniosacral division of the autonomic nervous system. These cholinergic nervesare associated with normal body functions (e.g., smooth muscle in blood vessels, salivary glands,and GI tract).paresthesia (also paraesthesia) A skin sensation, such as burning, prickling, itching, or tingling,with no apparent physical cause.Parkinsonism A group of neurologic disorders characterized by hypokinesia, tremor, and muscularrigidity.PEL See permissible exposure limit.percutaneous absorption The transfer of a chemical from the outer surface of the skin through thehorny layer (dead cells), through the epidermis, and into the systemic circulation. A variety offactors, such as pH, extent of ionization, molecular size, and water and lipid solubility governtransfer of chemicals through the skin.perinatal toxicology The study of toxic responses to occupationally or environmentally encounteredsubstances during a woman’s exposure to those substances from the time of conception throughthe neonatal period.peripheral neuritis Inflammation of the nerve ending or of terminal nerves.permissible exposure limit (PEL) A measure of the toxicity of a substance, established by the U.S.Department of Labor, Occupational Safety and Health Administration (OSHA); an 8-h, timeweightedaverage (TWA) limit of exposure is most commonly used. The limit is commonlyexpressed as the concentration of a substance per unit of air volume (mg/m 3 , ppm, fibers/cm 3 , etc.)