Primary structural defect of an organ is termed ?
Ans. is 'a' i.e., MalformationErrors in morphogenesis o There are four basic error in morphogenesis.Malformation o Malformation represent primary error of morphogenesis.o It arises from intrinsically abnormal development processo There is primary structural defect of an organ or bodyo In simple words, in malformation there is primary problem in morphogenesis.Deformation o As the name suggests (deformation), there is alteration in shape or structure of a pa that has differentiated normally.o This represents the normal response of a tissue to unusual mechanical forces.o For example, CTEV caused by intrauterine molding due to excessive pressure in oligohydraminious.o That means, in deformation the pa had developed normally, but due to unusual pressure deformity takes place. o As there is no error in organogenesis, it is referred to as secondary error in morphogenesis and is due to extrinsicdisturbance of development process (due to excessive pressure).Disruption o Disruption results from breakdown of the tissue that was previously normal in development, i.e. secondary destruction of previously normal organ or body region.o For example, congenital amputation due to constriction amniotic band.o As there is no error in organogenesis, it is referred to as secondary error in morphogenesis and is due to extrinsic disturbance of development process (due to constriction band).o Dysplasia is an abnormal organization of cells.Sequence o When a single primary structural defect in morphogenesis produces multiple anomalies through a cascading process of secondary and teiary problems in morphogenesis.o For example in spina bifida, the primary defect is single i.e. failure to close neural tube, which results in secondary anomalies such as club foot due to neuromuscular imbalance, bladder and bowel problems due to neuromuscular imbalance etc.o Depending upon the initating event, sequence may be:i) Malformation sequence Initiating event is malformationii) Deformation sequence --) Initiating event is deformationiii) Disruption sequence --) Initiating event is disruptionSyndrome (multiple malformation syndrome) o In multiple malformation syndrome, there is primary developmental anamoly of two or more system (In contrast to sequence where the primary structural defect is single.o So, a syndrome is a constellation of congenital anomalies that cannot to be explained to arise in a sequence.Association o The term association refers to a non random association of malformations for which it has not been determined whether the pattern is a sequence or a syndrome.
Malformation
Disruption
Deformation
Association