Tissue Fixation and Dehydration Techniques

To slow tissue metabolism, enhance coloration, preserve structure, and facilitate examination.

A good fixative has rapid penetration, quick reaction, minimal alteration, safety, and low cost.

Maintaining a pH of 7.2-7.4 ensures fixative stability and effective tissue preservation.

Time, temperature, tissue type (e.g., soft, hard), and fixative chemical properties affect fixation.

Dehydration replaces water in tissues with non-polar substances for better preservation.

Intermediate fluids help transition tissues from dehydration to paraffin infiltration.

Granulation tissue consists of fibroblasts, loose connective tissue, new capillaries, inflammatory cells.

A typical change in cell aging is the shortening of telomeres.

Myocardial infarction is characterized by coagulative necrosis.

Lynch syndrome is associated with an increased risk of certain cancers, particularly lung cancer.

High HDL levels are NOT associated with the development of atherosclerosis.

MiRNA do not encode proteins; they regulate gene expression instead.

Cushing's ulcers are commonly associated with severe burns or stress responses.

Respiratory distress syndrome lacks prominent neutrophilic inflammation in pulmonary tissue.

Caseous necrosis is seen in tuberculosis infections.

Cardiac muscle hypertrophies during spontaneous pulmonary emphysema.

Pancreatic enzymatic necrosis shows abundant infiltration with neutrophils.

Steatosis is the accumulation of fats in cells, like in cardiomyocytes.

Exposure to UV radiation is the primary risk factor for skin cancer.

Chronic inflammation is caused by prolonged irritation from toxic substances.

The five cardinal signs are calor, rubor, tumor, dolor, and function laesa.

Phimosis is the inability to retract the prepuce easily over the glans penis.

Hypospadias is the urethral opening found on the ventral aspect of the penis.

Epispadias is an abnormal urethral opening on the dorsal aspect of the penis.

Wound healing can be impaired by infection, diabetes, and poor perfusion.

Congenital malformations are the most common cause of infant mortality.