The area where this metaplasia happens is called the transformation zone. The epithelium undergoes metaplasia to become stratified squamous epithelium like the rest of the vagina as this is better suited to the conditions. When the cervix everts, the columnar epithelium that lines it meets the acidic environment of the vagina. Metaplasia is the transformation of tissue from one type of cell to another, for example a squamous epithelial cell to a cuboidal epithelial cell.Īn example of physiological metaplasia is the squamous metaplasia that occurs in the cervix. It can also occur due to inactivity, pressure, ischaemia, and chronic inflammation.ĭiagram - The difference between normal and atrophied muscleĬreative commons source by OpenStax Pathological atrophy can happen through catabolic metabolism due to malnutrition, whether this be caused by diseases such as cancer or by nutritional deficit.

When an individual gets older, most systems and tissues undergo some level of atrophy. For example, the uterus and breasts both reduce in size post-pregnancy. This can happen by a decrease in cell number and/or cell size.Ītrophy occurs physiologically in involution - when a tissue reduce in size after having increased in size. This is an Advert - we use these to keep SimpleMed free! If you see something you like, please click on it - it supports the site :)Ītrophy is the opposite of hyperplasia and hypertrophy, in essence, it is the shrinkage of tissue. The increased cell replication increases the chance of dysplasia (discussed later), and then neoplasia, taking place.ĭiagram - The differences between hyperplasia and hypertrophyĬreative commons source by SchwarzeMelancholie Pathological hyperplasia can occur in overstimulation of endometrial tissue with oestrogen, for example in women taking unopposed oestrogen (without progesterone) for hormone replacement therapy after the menopause. Hyperplasia is also the method by which the liver restores itself from a partial resection. Physiological hyperplasia occurs in the endometrium of the uterus upon stimulation of oestrogen during the menstrual cycle.

Hyperplasia is the increase in the size of a tissue by an increase in the number of cells in that tissue. Too much cardiac hypertrophy can result in the muscular walls of the heart being too thick to effectively pump blood through the body causing heart failure. In hypertension there is often pathological hypertrophy of the cardiac tissue, due to the increased strain on the ventricles and atria of the heart. Smooth muscle hypertrophy occurs in the uterus, stimulated by hormonal changes.

Hypertrophy can occur both physiologically and pathologically. A common cause of physiological hypertrophy is increased skeletal muscle mass gained through anabolic metabolism following exercise. The intracellular organelles, cytoplasm and structural proteins all increase in these enlarged cells, but the number of cells in the tissue remains the same. Hypertrophy is the increase in the size of a tissue via the enlargement of cells. These chemicals can prompt apoptosis, cell division and cell differentiation, or resist apoptosis. Chemical mediators are able to signal cells to undertake a number of actions. In response to physiological and pathological stimuli, cells can undergo changes which make them more suited for their environment.

Pathological hypertrophy definition