LAB(1)

CELL INJURIES&

ADAPTATION

Normal Cell

stress

adaptation

Fail to adapt

injuries

atrophy. hypertrophy. Hyperplasia. dysplasia. metaplasia.

Reversible

Cellular Swelling Fatty Change

Irreversible

Necrosis Apoptosis

cellular adaptation Cellular adaptation is a state that lies intermediate between the normal (unstressed )cell and the injured (over stressed cells).

The adaptation may be physiological (normal) or pathological (abnormal).

Five major types of adaptation include1. atrophy.2. hypertrophy. 3. Hyperplasia.4. dysplasia.5. metaplasia.

NormalAtrophy

ATROPHY: decrease in cell size

The kidney at the left has undergone atrophy and is much smaller than the normal kidney at the right.

HYPERTROPHY: increase in cell size

This is cardiac pathological hypertrophy involving the left ventricle. The number of myocardial fibers does not increase, but their size can increasein response to an increased workload, leading to the marked thickening of the left ventricle in this patient with systemic hypertension.

normal hypertrophy

Normal uterus gravid uterus

gross appearance of a normal uterus (1) and a gravid uterus (2) that was removed for postpartum bleeding

Physiologic hypertrophy of the uterus during pregnancy

(1)(2) (1) (2)

The folds of endometrium in this uterus opened to reveal the endometrial cavity are an example of hyperplasia. Cells have increased in number. As a result, the size of the endometrium has increased. This increase is physiologic with a normal menstrual cycle.

HYPERPLASIA: increase in the number of cells

Cut surface of normal uterus Uterus with hyperplasia

folds

METAPLASIA: occurs when a differentiated cell of a certain type is replaced by another cell type.

Metaplasia is not a normal physiologic process and may be the first step toward neoplasia.

Dysplasia abnormal changes in cellular shape,size, and/or organization

Normal kidney Multicystic Renal Dysplasia