Changes

==Pathological changes to cells==

==Pathological changes to cells==

Generally, disruptions at a cellular level usually involve changes or damage to the cells themselves, or they involve the presence of unexpected material within the cell, such as [[Pigmentation and Calcification - Pathology|pigments]] or [[Pigmentation and Calcification - Pathology|calcified material]]. When cells begin to [[Degenerations and Infiltrations - Pathology|degenerate]] or become [[Degenerations and Infiltrations - Pathology|infiltrated]] by foreign material then cellular metabolism has been disrupted. The alteration in the structure of the cell can be suggestive of the metabolic abnormality that has occured, and result in the cellular parameters extending beyond the normal physiological range for the cell.

These are best considered at a cellular level.

These structural changes are deviations from the cell's normal structure and function.

Parameters are outside the normal physiological range for the cell. [[Degenerations and Infiltrations - Pathology]]

Enter body from environment [[Pigmentation and Calcification - Pathology]]

Atrophy is a decrease in the size of the cells and organ, occurring after the organ has reached normal size. Hypertrophy is an increase in the size of an organ due to an increase in size of the individual cells. Hypoplasia is a reduction in the size of cells and tissues,.

Due to a failure to grow to normal size.

*'''Atrophy''' is a decrease in the size of the cells and respective organ(s), occurring after the organ has reached it's normal size.  

Ranges from mild hypoplasia to almost complete absence.  

*'''Hypertrophy''' is an increase in the size of an organ due to an increase in size of the individual cells.  

*'''Hypoplasia''' is a reduction in the size of cells and tissues due to a failure to grow to the normal size which ranges from mild hypoplasia to almost complete absence.  

Almost complete absence is also called vestigial or rudimentary.  

Almost complete absence is also called vestigial or rudimentary.  

Aplasia and agensis refer to complete absence of tissue.  

*'''Aplasia''' and '''agensis''' refer to complete absence of tissue.  

*'''Hyperplasia''' is an increase in the size of an organ due to an increase in the numbers of cells present within it.  

Some rudimentary tissue can be seen if searched for carefully. Hyperplasia is an increase in the size of an organ due to an increase in the numbers of cells present within it.  

Hypertrophy and hyperplasia may occur concurrently.  

Hypertrophy and hyperplasia may occur concurrently.  

*'''Metaplasia''' is a transformation of one type of tissue into another and occurs solely in connective tissue and epithelium.

Hyperplastic tissue is more prone to injury by chemicals, and also may be more prone to undergo neoplastic change in some casesMetaplasia is a transformation of one type of tissue into another.

*'''Dysplasia''' is abnormal growth within a tissue

Occurs solely in:

*'''Anaplasia''' is a marked and irreversible loss of cellular differentiation with return to a more primitive state, which can be a feature of highly malignant tumours.  

Connective tissue  

*'''Neoplasia''' is a serious disturbance of growth of tissues

The metaplastic change id to cartilage and bone in damaged tissue.

 

 

Squamous metaplasia of cuboidal or columnar epithelium is quite common.  

Seen in the prostate of dogs under the influence of oestrogens. Dysplasia is abnormal growth within a tissueAnaplasia is a marked and irreversible loss of cellular differentiation with return to a more primitive state.

Afeature of highly malignant tumours. Neoplasia is a serious disturbance of growth of tissues[[Disorders of Cell Growth - Pathology]]

Necrosis means the death of cells within the living body.  

Necrosis means the death of cells within the living body.