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Term
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Definition
| this ia an abnormal mass of tissue whose growth exceeds and is un coordinated with that of normal tissue and persists even after cessation of the stimuli which started the change |
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Term
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Definition
There are two main types:
>benign tumours
>malignant tumours |
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Definition
The names of these tumours and with -oma
Eg: adenomas-benign epithelial tumors arising in glands forming glandular patterns |
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Term
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Definition
These are also called cancers and are divided into two general categories:
>carcinomas-arising from epithelial tissue
>sarcomas-arising from mesenchymal tissue
Eg adenocarcinoma-malignant growth tumours forming glandular patterns
NB: some tumors arise from more than one parencymal cell type
>mixed tumours-from one germ layer that diffrentiates into more than one parenchymal cell type.
>teratomas-made up from parenchymal cells from more than one germ layer. |
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TUMOURS ARE CLASSIFIED BASED ON
a>DIFFRENTIATION
b>RATE OF GROWTH
c>LOCAL INVASION
d>METASTASES |
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Definition
a>Diffrentiation-is the extent to which tumor cells resemble comparable normal tissue.
Anaplasia-this is lack of diffrentiation whereby there is
*nuclear and cellular pleomorphism
*hyperchromasia
*increased nuclear-cytoplasmic ratio
*abundant mitoses
*loss of polarity
*tumor giant cells
b>Rate of growth-is the rate at which the tumour grows.
c>Local invasion-is whether the tumor invades the surrounding normal tissue or is confined within its capsule.
d>metastases-is the ability of whether the tumour can spread to distant sites and th routes by which this can occur are
1.spread into body cavities
2.invasion of lymphatics.
3.hematogenous spread-via the blood circulation.this is typical of all sarcomas and a few carcinomas |
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| DIFFRENCES BETWEEN THE BENIGN AND MALIGNANT TUMOURS. |
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Definition
a>diffrentiation
*benign-are normally well diffrentiated and normally resemble the surrounding normal tissue
*malignant-range from well diffrentiated to poorly diffrentiated cells and there may also be a total lack of diffrentiation (anaplasia)
b>Rate of growth:
*benign-is normally slow and may take years to develope
*malignant-the rate is normally rapid
c>Local invasion:
*benign-does not invade the surrounding nornal tissue and the tumors are mostly encapsulated.
*malignant-are invasive and infiltrative and destroy the surrounding normal tissue.
d>Metastases:
*benign-does not metastasize.
*malignant-metastases is the hallmark for malignant tumours. |
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